Patent Application
20110206658
The present invention is directed to compositions of matter useful for the treatment of hematopoietic tumor in mammals and to methods of using those compositions of matter for the same.
Malignant tumors (cancers) are the second leading cause of death in the United States, after heart disease (Boring et al., CA Cancel J. Clin. 43:7 (1993)). Cancer is characterized by the increase in the number of abnormal, or neoplastic, cells derived from a normal tissue which proliferate to form a tumor mass, the invasion of adjacent tissues by these neoplastic tumor cells, and the generation of malignant cells which eventually spread via the blood or lymphatic system to regional lymph nodes and to distant sites via a process called metastasis. In a cancerous state, a cell proliferates under conditions in which normal cells would not grow. Cancer manifests itself in a wide variety of forms, characterized by different degrees of invasiveness and aggressiveness.
Cancers which involve cells generated during hematopoiesis, a process by which cellular elements of blood, such as lymphocytes, leukocytes, platelets, erythrocytes and natural killer cells are generated are referred to as hematopoietic cancers. Lymphocytes which can be found in blood and lymphatic tissue and are critical for immune response are categorized into two main classes of lymphocytes: B lymphocytes (B cells) and T lymphocytes (T cells), which mediate humoral and cell mediated immunity, respectively.
B cells mature within the bone marrow and leave the marrow expressing an antigen-binding antibody on their cell surface. When a naive B cell first encounters the antigen for which its membrane-bound antibody is specific, the cell begins to divide rapidly and its progeny differentiate into memory B cells and effector cells called “plasma cells”. Memory B cells have a longer life span and continue to express membrane-bound antibody with the same specificity as the original parent cell. Plasma cells do not produce membrane-bound antibody but instead produce the antibody in a form that can be secreted. Secreted antibodies are the major effector molecule of humoral immunity.
T cells mature within the thymus which provides an environment for the proliferation and differentiation of immature T cells. During T cell maturation, the T cells undergo the gene rearrangements that produce the T-cell receptor and the positive and negative selection which helps determine the cell-surface phenotype of the mature T cell. Characteristic cell surface markers of mature T cells are the CD3:T-cell receptor complex and one of the coreceptors, CD4 or CD8.
In attempts to discover effective cellular targets for cancer therapy, researchers have sought to identify transmembrane or otherwise membrane-associated polypeptides that are specifically expressed on the surface of one or more particular type(s) of cancer cell as compared to on one or more normal non-cancerous cell(s). Often, such membrane-associated polypeptides are more abundantly expressed on the surface of the cancer cells as compared to on the surface of the non-cancerous cells. The identification of such tumor-associated cell surface antigen polypeptides has given rise to the ability to specifically target cancer cells for destruction via antibody-based therapies. In this regard, it is noted that antibody-based therapy has proved very effective in the treatment of certain cancers. For example, HERCEPTIN® and RITUXAN® (both from Genentech Inc., South San Francisco, Calif.) are antibodies that have been used successfully to treat breast cancer and non-Hodgkin's lymphoma, respectively. More specifically, HERCEPTIN® is a recombinant DNA-derived humanized monoclonal antibody that selectively binds to the extracellular domain of the human epidermal growth factor receptor 2 (HER2) protooncogene. HER2 protein overexpression is observed in 25-30% of primary breast cancers. RITUXAN® is a genetically engineered chimeric murine/human monoclonal antibody directed against the CD20 antigen found on the surface of normal and malignant B lymphocytes. Both these antibodies are recombinantly produced in CHO cells.
In other attempts to discover effective cellular targets for cancer therapy, researchers have sought to identify (1) non-membrane-associated polypeptides that are specifically produced by one or more particular type(s) of cancer cell(s) as compared to by one or more particular type(s) of non-cancerous normal cell(s), (2) polypeptides that are produced by cancer cells at an expression level that is significantly higher than that of one or more normal non-cancerous cell(s), or (3) polypeptides whose expression is specifically limited to only a single (or very limited number of different) tissue type(s) in both the cancerous and non-cancerous state (e.g., normal prostate and prostate tumor tissue). Such polypeptides may remain intracellularly located or may be secreted by the cancer cell. Moreover, such polypeptides may be expressed not by the cancer cell itself, but rather by cells which produce and/or secrete polypeptides having a potentiating or growth-enhancing effect on cancer cells. Such secreted polypeptides are often proteins that provide cancer cells with a growth advantage over normal cells and include such things as, for example, angiogenic factors, cellular adhesion factors, growth factors, and the like. Identification of antagonists of such non-membrane associated polypeptides would be expected to serve as effective therapeutic agents for the treatment of such cancers. Furthermore, identification of the expression pattern of such polypeptides would be useful for the diagnosis of particular cancers in mammals.
Despite the above identified advances in mammalian cancer therapy, there is a great need for additional therapeutic agents capable of detecting the presence of tumor in a mammal and for effectively inhibiting neoplastic cell growth, respectively. Accordingly, it is an objective of the present invention to identify polypeptides, cell membrane-associated, secreted or intracellular polypeptides whose expression is specifically limited to only a single (or very limited number of different) tissue type(s), hematopoietic tissues, in both a cancerous and non-cancerous state, and to use those polypeptides, and their encoding nucleic acids, to produce compositions of matter useful in the therapeutic treatment detection of hematopoietic cancer in mammals.
CD79 is the signaling component of the B-cell receptor consisting of a covalent heterodimer containing CD79a (Igα, mb-1) and CD79b (Igβ, B29). CD79a and CD79b each contain an extracellular immunoglobulin (Ig) domain, a transmembrane domain, and an intracellular signaling domain, an immunoreceptor tyrosine-based activation motif (ITAM) domain. CD79 expression is restricted to B cells and is expressed in Non-Hodgkin's Lymphoma cells (NHLs) (Cabezudo et al., Haematologica, 84:413-418 (1999); D'Arena et al., Am. J. Hematol., 64: 275-281 (2000); Olejniczak et al., Immunol. Invest., 35: 93-114 (2006)). CD79a and CD79b and sIg are all required for surface expression of the CD79 (Matsuuchi et al., Curr. Opin. Immunol., 13(3): 270-7)). The average surface expression of CD79b on NHLs is similar to that on normal B-cells, but with a greater range (Matsuuchi et al., Curr. Opin. Immunol., 13(3): 270-7 (2001)).
Thus, it is beneficial to produce therapeutic antibodies to the CD79a and CD79b antigen that create minimal or no antigenicity when administered to patients, especially for chronic treatment. The present invention satisfies this and other needs. The present invention provides anti-CD79a and anti-CD79b antibodies that overcome the limitations of current therapeutic compositions as well as offer additional advantages that will be apparent from the detailed description below.
The use of antibody-drug conjugates (ADC), i.e. immunoconjugates, for the local delivery of cytotoxic or cytostatic agents, i.e. drugs to kill or inhibit tumor cells in the treatment of cancer (Lambert, J. (2005) Curr. Opinion in Pharmacology 5:543-549; Wu et al (2005) Nature Biotechnology 23(9):1137-1146; Payne, G. (2003) Cancer Cell 3:207-212; Syrigos and Epenetos (1999) Anticancer Research 19:605-614; Niculescu-Duvaz and Springer (1997) Adv. Drug Del. Rev. 26:151-172; U.S. Pat. No. 4,975,278) allows targeted delivery of the drug moiety to tumors, and intracellular accumulation therein, where systemic administration of these unconjugated drug agents may result in unacceptable levels of toxicity to normal cells as well as the tumor cells sought to be eliminated (Baldwin et al (1986) Lancet pp. (Mar. 15, 1986):603-05; Thorpe, (1985) “Antibody Carriers Of Cytotoxic Agents In Cancer Therapy: A Review,” in Monoclonal Antibodies '84: Biological And Clinical Applications, A. Pinchera et al (ed.s), pp. 475-506). Efforts to improve the therapeutic index, i.e. maximal efficacy and minimal toxicity of ADC have focused on the selectivity of polyclonal (Rowland et al (1986) Cancer Immunol. Immunother., 21:183-87) and monoclonal antibodies (mAbs) as well as drug-linking and drug-releasing properties (Lambert, J. (2005) Curr. Opinion in Pharmacology 5:543-549). Drug moieties used in antibody drug conjugates include bacterial protein toxins such as diphtheria toxin, plant protein toxins such as ricin, small molecules such as auristatins, geldanamycin (Mandler et al (2000) J. of the Nat. Cancer Inst. 92(19):1573-1581; Mandler et al (2000) Bioorganic & Med. Chem. Letters 10:1025-1028; Mandler et al (2002) Bioconjugate Chem. 13:786-791), maytansinoids (EP 1391213; Liu et al (1996) Proc. Natl. Acad. Sci. USA 93:8618-8623), calicheamicin (Lode et al (1998) Cancer Res. 58:2928; Hinman et al (1993) Cancer Res. 53:3336-3342), daunomycin, doxorubicin, methotrexate, and vindesine (Rowland et al (1986) supra). The drug moieties may affect cytotoxic and cytostatic mechanisms including tubulin binding, DNA binding, or topoisomerase inhibition. Some cytotoxic drugs tend to be inactive or less active when conjugated to large antibodies or protein receptor ligands.
The auristatin peptides, auristatin E (AE) and monomethylauristatin (MMAE), synthetic analogs of dolastatin (WO 02/088172), have been conjugated as drug moieties to: (i) chimeric monoclonal antibodies cBR96 (specific to Lewis Y on carcinomas); (ii) cAC10 which is specific to CD30 on hematological malignancies (Klussman, et al (2004), Bioconjugate Chemistry 15(4):765-773; Doronina et al (2003) Nature Biotechnology 21(7):778-784; Francisco et al (2003) Blood 102(4):1458-1465; US 2004/0018194; (iii) anti-CD20 antibodies such as rituxan (WO 04/032828) for the treatment of CD20-expressing cancers and immune disorders; (iv) anti-EphB2R antibody 2H9 for treatment of colorectal cancer (Mao et al (2004) Cancer Research 64(3):781-788); (v) E-selectin antibody (Bhaskar et al (2003) Cancer Res. 63:6387-6394); (vi) trastuzumab (HERCEPTIN®, US 2005/0238649), and (vi) anti-CD30 antibodies (WO 03/043583). Variants of auristatin E are disclosed in U.S. Pat. No. 5,767,237 and U.S. Pat. No. 6,124,431. Monomethyl auristatin E conjugated to monoclonal antibodies are disclosed in Senter et al, Proceedings of the American Association for Cancer Research, Volume 45, Abstract Number 623, presented Mar. 28, 2004. Auristatin analogs MMAE and MMAF have been conjugated to various antibodies (US 2005/0238649).
Conventional means of attaching, i.e. linking through covalent bonds, a drug moiety to an antibody generally leads to a heterogeneous mixture of molecules where the drug moieties are attached at a number of sites on the antibody. For example, cytotoxic drugs have typically been conjugated to antibodies through the often-numerous lysine residues of an antibody, generating a heterogeneous antibody-drug conjugate mixture. Depending on reaction conditions, the heterogeneous mixture typically contains a distribution of antibodies with from 0 to about 8, or more, attached drug moieties. In addition, within each subgroup of conjugates with a particular integer ratio of drug moieties to antibody, is a potentially heterogeneous mixture where the drug moiety is attached at various sites on the antibody. Analytical and preparative methods may be inadequate to separate and characterize the antibody-drug conjugate species molecules within the heterogeneous mixture resulting from a conjugation reaction. Antibodies are large, complex and structurally diverse biomolecules, often with many reactive functional groups. Their reactivities with linker reagents and drug-linker intermediates are dependent on factors such as pH, concentration, salt concentration, and co-solvents. Furthermore, the multistep conjugation process may be nonreproducible due to difficulties in controlling the reaction conditions and characterizing reactants and intermediates.
Cysteine thiols are reactive at neutral pH, unlike most amines which are protonated and less nucleophilic near pH 7. Since free thiol (RSH, sulfhydryl) groups are relatively reactive, proteins with cysteine residues often exist in their oxidized form as disulfide-linked oligomers or have internally bridged disulfide groups. Extracellular proteins generally do not have free thiols (Garman, 1997, Non-Radioactive Labelling: A Practical Approach, Academic Press, London, at page 55). Antibody cysteine thiol groups are generally more reactive, i.e. more nucleophilic, towards electrophilic conjugation reagents than antibody amine or hydroxyl groups. Cysteine residues have been introduced into proteins by genetic engineering techniques to form covalent attachments to ligands or to form new intramolecular disulfide bonds (Better et al (1994) J. Biol. Chem. 13:9644-9650; Bernhard et al (1994) Bioconjugate Chem. 5:126-132; Greenwood et al (1994) Therapeutic Immunology 1:247-255; Tu et al (1999) Proc. Natl. Acad. Sci. USA 96:4862-4867; Kanno et al (2000) J. of Biotechnology, 76:207-214; Chmura et al (2001) Proc. Nat. Acad. Sci. USA 98(15):8480-8484; U.S. Pat. No. 6,248,564). However, engineering in cysteine thiol groups by the mutation of various amino acid residues of a protein to cysteine amino acids is potentially problematic, particularly in the case of unpaired (free Cys) residues or those which are relatively accessible for reaction or oxidation. In concentrated solutions of the protein, whether in the periplasm of E. coli, culture supernatants, or partially or completely purified protein, unpaired Cys residues on the surface of the protein can pair and oxidize to form intermolecular disulfides, and hence protein dimers or multimers. Disulfide dimer formation renders the new Cys unreactive for conjugation to a drug, ligand, or other label. Furthermore, if the protein oxidatively forms an intramolecular disulfide bond between the newly engineered Cys and an existing Cys residue, both Cys thiol groups are unavailable for active site participation and interactions. Furthermore, the protein may be rendered inactive or non-specific, by misfolding or loss of tertiary structure (Zhang et al (2002) Anal. Biochem. 311:1-9).
Cysteine-engineered antibodies have been designed as FAB antibody fragments (thioFab) and expressed as full-length, IgG monoclonal (thioMab) antibodies (US 2007/0092940, the contents of which are incorporated by reference). ThioFab and ThioMab antibodies have been conjugated through linkers at the newly introduced cysteine thiols with thiol-reactive linker reagents and drug-linker reagents to prepare antibody drug conjugates (Thio ADC).
All references cited herein, including patent applications and publications, are incorporated by reference in their entirety.
In the present specification, Applicants describe for the first time the identification of various cellular polypeptides (and their encoding nucleic acids or fragments thereof) which are specifically expressed by both tumor and normal cells of a specific cell type, for example cells generated during hematopoiesis, i.e. lymphocytes, leukocytes, erythrocytes and platelets. All of the above polypeptides are herein referred to as Tumor Antigens of Hematopoietic Origin polypeptides (“TAHO” polypeptides) and are expected to serve as effective targets for cancer therapy in mammals.
The invention provides anti-CD79a and anti-CD79b antibodies or functional fragments thereof, and their method of use in the treatment of hematopoietic tumors.
Accordingly, in one embodiment of the present invention, the invention provides an isolated nucleic acid molecule having a nucleotide sequence that encodes a tumor antigen of hematopoietic origin polypeptide (a “TAHO” polypeptide) or fragment thereof.
In certain aspects, the isolated nucleic acid molecule comprises a nucleotide sequence having at least about 80% nucleic acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% nucleic acid sequence identity, to (a) a DNA molecule encoding a full-length TAHO polypeptide having an amino acid sequence as disclosed herein, a TAHO polypeptide amino acid sequence lacking the signal peptide as disclosed herein, an extracellular domain of a transmembrane TAHO polypeptide, with or without the signal peptide, as disclosed herein or any other specifically defined fragment of a full-length TAHO polypeptide amino acid sequence as disclosed herein, or (b) the complement of the DNA molecule of (a).
In other aspects, the isolated nucleic acid molecule comprises a nucleotide sequence having at least about 80% nucleic acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% nucleic acid sequence identity, to (a) a DNA molecule comprising the coding sequence of a full-length TAHO polypeptide cDNA as disclosed herein, the coding sequence of a TAHO polypeptide lacking the signal peptide as disclosed herein, the coding sequence of an extracellular domain of a transmembrane TAHO polypeptide, with or without the signal peptide, as disclosed herein or the coding sequence of any other specifically defined fragment of the full-length TAHO polypeptide amino acid sequence as disclosed herein, or (b) the complement of the DNA molecule of (a).
In further aspects, the invention concerns an isolated nucleic acid molecule comprising a nucleotide sequence having at least about 80% nucleic acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% nucleic acid sequence identity, to (a) a DNA molecule that encodes the same mature polypeptide encoded by the full-length coding region of any of the human protein cDNAs deposited with the ATCC as disclosed herein, or (b) the complement of the DNA molecule of (a).
Another aspect of the invention provides an isolated nucleic acid molecule comprising a nucleotide sequence encoding a TAHO polypeptide which is either transmembrane domain-deleted or transmembrane domain-inactivated, or is complementary to such encoding nucleotide sequence, wherein the transmembrane domain(s) of such polypeptide(s) are disclosed herein. Therefore, soluble extracellular domains of the herein described TAHO polypeptides are contemplated.
In other aspects, the present invention is directed to isolated nucleic acid molecules which hybridize to (a) a nucleotide sequence encoding a TAHO polypeptide having a full-length amino acid sequence as disclosed herein, a TAHO polypeptide amino acid sequence lacking the signal peptide as disclosed herein, an extracellular domain of a transmembrane TAHO polypeptide, with or without the signal peptide, as disclosed herein or any other specifically defined fragment of a full-length TAHO polypeptide amino acid sequence as disclosed herein, or (b) the complement of the nucleotide sequence of (a). In this regard, an embodiment of the present invention is directed to fragments of a full-length TAHO polypeptide coding sequence, or the complement thereof, as disclosed herein, that may find use as, for example, hybridization probes useful as, for example, detection probes, antisense oligonucleotide probes, or for encoding fragments of a full-length TAHO polypeptide that may optionally encode a polypeptide comprising a binding site for an anti-TAHO polypeptide antibody, a TAHO binding oligopeptide or other small organic molecule that binds to a TAHO polypeptide. Such nucleic acid fragments are usually at least about 5 nucleotides in length, alternatively at least about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, or 1000 nucleotides in length, wherein in this context the term “about” means the referenced nucleotide sequence length plus or minus 10% of that referenced length. It is noted that novel fragments of a TAHO polypeptide-encoding nucleotide sequence may be determined in a routine manner by aligning the TAHO polypeptide-encoding nucleotide sequence with other known nucleotide sequences using any of a number of well known sequence alignment programs and determining which TAHO polypeptide-encoding nucleotide sequence fragment(s) are novel. All of such novel fragments of TAHO polypeptide-encoding nucleotide sequences are contemplated herein. Also contemplated are the TAHO polypeptide fragments encoded by these nucleotide molecule fragments, preferably those TAHO polypeptide fragments that comprise a binding site for an anti-TAHO antibody, a TAHO binding oligopeptide or other small organic molecule that binds to a TAHO polypeptide.
In a certain aspect, the invention concerns an isolated TAHO polypeptide, comprising an amino acid sequence having at least about 80% amino acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% amino acid sequence identity, to a TAHO polypeptide having a full-length amino acid sequence as disclosed herein, a TAHO polypeptide amino acid sequence lacking the signal peptide as disclosed herein, an extracellular domain of a transmembrane TAHO polypeptide protein, with or without the signal peptide, as disclosed herein, an amino acid sequence encoded by any of the nucleic acid sequences disclosed herein or any other specifically defined fragment of a full-length TAHO polypeptide amino acid sequence as disclosed herein.
In a further aspect, the invention concerns an isolated TAHO polypeptide comprising an amino acid sequence having at least about 80% amino acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% amino acid sequence identity, to an amino acid sequence encoded by any of the human protein cDNAs deposited with the ATCC as disclosed herein.
In a specific aspect, the invention provides an isolated TAHO polypeptide without the N-terminal signal sequence and/or without the initiating methionine and is encoded by a nucleotide sequence that encodes such an amino acid sequence as hereinbefore described. Processes for producing the same are also herein described, wherein those processes comprise culturing a host cell comprising a vector which comprises the appropriate encoding nucleic acid molecule under conditions suitable for expression of the TAHO polypeptide and recovering the TAHO polypeptide from the cell culture.
Another aspect of the invention provides an isolated TAHO polypeptide which is either transmembrane domain-deleted or transmembrane domain-inactivated. Processes for producing the same are also herein described, wherein those processes comprise culturing a host cell comprising a vector which comprises the appropriate encoding nucleic acid molecule under conditions suitable for expression of the TAHO polypeptide and recovering the TAHO polypeptide from the cell culture.
In other embodiments of the present invention, the invention provides vectors comprising DNA encoding any of the herein described polypeptides. Host cells comprising any such vector are also provided. By way of example, the host cells may be CHO cells, E. coli cells, or yeast cells. A process for producing any of the herein described polypeptides is further provided and comprises culturing host cells under conditions suitable for expression of the desired polypeptide and recovering the desired polypeptide from the cell culture.
In other embodiments, the invention provides isolated chimeric polypeptides comprising any of the herein described TAHO polypeptides fused to a heterologous (non-TAHO) polypeptide. Example of such chimeric molecules comprise any of the herein described TAHO polypeptides fused to a heterologous polypeptide such as, for example, an epitope tag sequence or a Fc region of an immunoglobulin.
In another embodiment, the invention provides an antibody which binds, preferably specifically, to any of the above or below described polypeptides. Optionally, the antibody is a monoclonal antibody, antibody fragment, including Fab, Fab′, F(ab′)2, and Fv fragment, diabody, single domain antibody, chimeric antibody, humanized antibody, single-chain antibody or antibody that competitively inhibits the binding of an anti-TAHO polypeptide antibody to its respective antigenic epitope. Antibodies of the present invention may optionally be conjugated to a growth inhibitory agent or cytotoxic agent such as a toxin, including, for example, a maytansinoid, a dolostatin derivative or a calicheamicin, an antibiotic, a radioactive isotope, a nucleolytic enzyme, or the like. The antibodies of the present invention may optionally be produced in CHO cells or bacterial cells and preferably induce death of a cell to which they bind. For detection purposes, the antibodies of the present invention may be detectably labeled, attached to a solid support, or the like.
In another embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody comprises:
(a) a light chain variable domain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 97, 99 or 101; and/or
(b) a heavy chain variable domain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 98, 100 or 102.
In another embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody comprises:
(a) a light chain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 10, 33 or 41; and/or
(b) a heavy chain variable domain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 12, 35 or 43.
In another embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody binds to an epitope within a region of a TAHO polypeptide, such as human CD79b (TAHOS) and/or cyno CD79b (TAHO40) polypeptides, selected from the group comprising:
(a) an amino acid sequence comprising amino acids 29-39 of SEQ ID NO: 4;
(b) an amino acid sequence comprising amino acids 30-40 of SEQ ID NO: 8; or
(c) an amino acid sequence comprising amino acids 29-39 of SEQ ID NO: 13.
In a further embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody binds to an epitope wherein said epitope comprises amino acids 29-39 of SEQ ID NO: 4, wherein the amino acid at position 30, 34 and 36 is Arg. In a further embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody binds to an epitope wherein said epitope comprises amino acids 29-39 of SEQ ID NO: 8, wherein the amino acid at position 35 is Leu.
In another embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody binds to an epitope within a region of a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein said epitope has at least 80% amino acid sequence identity to:
(a) an amino acid sequence comprising amino acids 29-39 of SEQ ID NO: 4;
(b) an amino acid sequence comprising amino acids 30-40 of SEQ ID NO: 8; or
(c) an amino acid sequence comprising amino acids 29-39 of SEQ ID NO: 13.
In a further embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody binds to an epitope wherein said epitope comprises amino acids 29-39 of SEQ ID NO: 4, wherein the amino acid at position 30, 34 and 36 is Arg. In a further embodiment, the invention provides an anti-TAHO antibody, wherein such anti-TAHO antibody binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides, wherein such anti-TAHO antibody binds to an epitope wherein said epitope comprises amino acids 29-39 of SEQ ID NO: 8, wherein the amino acid at position 35 is Leu.
In one aspect, the antibodies of the invention include cysteine engineered antibodies where one or more amino acids of a parent antibody are replaced with a free cysteine amino acid as disclosed in WO2006/034488; US 2007/0092940 (herein incorporated by reference in its entirety). Any form of anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, may be so engineered, i.e. mutated. For example, a parent Fab antibody fragment may be engineered to form a cysteine engineered Fab, referred to herein as “ThioFab.” Similarly, a parent monoclonal antibody may be engineered to form a “ThioMab.” It should be noted that a single site mutation yields a single engineered cysteine residue in a ThioFab, while a single site mutation yields two engineered cysteine residues in a ThioMab, due to the dimeric nature of the IgG antibody. The cysteine engineered anti-TAHO antibodies of the invention, such as anti-human CD79b (TAHO5) and anti-cyno CD79b (TAHO40) antibodies, include monoclonal antibodies, humanized or chimeric monoclonal antibodies, and antigen-binding fragments of antibodies, fusion polypeptides and analogs that preferentially bind cell-associated TAHO polypeptides, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides. A cysteine engineered antibody may alternatively comprise an antibody comprising a cysteine at a position disclosed herein in the antibody or Fab, resulting from the sequence design and/or selection of the antibody, without necessarily altering a parent antibody, such as by phage display antibody design and selection or through de novo design of light chain and/or heavy chain framework sequences and constant regions. A cysteine engineered antibody comprises one or more free cysteine amino acids having a thiol reactivity value in the ranges of 0.6 to 1.0; 0.7 to 1.0 or 0.8 to 1.0. A free cysteine amino acid is a cysteine residue which has been engineered into the parent antibody and is not part of a disulfide bridge. Cysteine engineered antibodies are useful for attachment of cytotoxic and/or imaging compounds at the site of the engineered cysteine through, for example, a maleimide or haloacetyl. The nucleophilic reactivity of the thiol functionality of a Cys residue to a maleimide group is about 1000 times higher compared to any other amino acid functionality in a protein, such as amino group of lysine residues or the N-terminal amino group. Thiol specific functionality in iodoacetyl and maleimide reagents may react with amine groups, but higher pH (>9.0) and longer reaction times are required (Garman, 1997, Non-Radioactive Labelling: A Practical Approach, Academic Press, London).
In an embodiment, a cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibodies, of the invention comprises an engineered cysteine at any one of the following positions, where the position is numbered according to Kabat et al. in the light chain (see Kabat et al (1991) Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md.) and according to EU numbering in the heavy chain (including the Fc region) (see Kabat et al. (1991), supra), wherein the light chain constant region depicted by underlining in
A cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, comprises one or more free cysteine amino acids wherein the cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibodies, binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptide, and is prepared by a process comprising replacing one or more amino acid residues of a parent anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibodies, by cysteine wherein the parent antibody comprises:
(a) a light chain variable domain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 97, 99 or 101; and/or
(b) a heavy chain variable domain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 98, 100 or 102.
A cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, comprises one or more free cysteine amino acids wherein the cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, binds to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptide, and is prepared by a process comprising replacing one or more amino acid residues of a parent anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, by cysteine wherein the parent antibody comprises:
(a) a light chain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 10, 33 or 41; and/or
(b) a heavy chain variable domain sequence having at least 90% sequence identity to an amino acid sequence selected from SEQ ID NO: 12, 35 or 43.
In a certain aspect, the invention concerns a cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, comprising an amino acid sequence having at least about 80% amino acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% amino acid sequence identity, to a cysteine engineered antibody having a full-length amino acid sequence as disclosed herein, or a cysteine engineered antibody amino acid sequence lacking the signal peptide as disclosed herein.
In a yet further aspect, the invention concerns an isolated cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, comprising an amino acid sequence that is encoded by a nucleotide sequence that hybridizes to the complement of a DNA molecule encoding (a) a cysteine engineered antibody having a full-length amino acid sequence as disclosed herein, (b) a cysteine engineered antibody amino acid sequence lacking the signal peptide as disclosed herein, (c) an extracellular domain of a transmembrane cysteine engineered antibody protein, with or without the signal peptide, as disclosed herein, (d) an amino acid sequence encoded by any of the nucleic acid sequences disclosed herein or (e) any other specifically defined fragment of a full-length cysteine engineered antibody amino acid sequence as disclosed herein.
In a specific aspect, the invention provides an isolated cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, without the N-terminal signal sequence and/or without the initiating methionine and is encoded by a nucleotide sequence that encodes such an amino acid sequence as described in. Processes for producing the same are also herein described, wherein those processes comprise culturing a host cell comprising a vector which comprises the appropriate encoding nucleic acid molecule under conditions suitable for expression of the cysteine engineered antibody and recovering the cysteine engineered antibody from the cell culture.
Another aspect of the invention provides an isolated cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, which is either transmembrane domain-deleted or transmembrane domain-inactivated. Processes for producing the same are also herein described, wherein those processes comprise culturing a host cell comprising a vector which comprises the appropriate encoding nucleic acid molecule under conditions suitable for expression of the cysteine engineered antibody and recovering the cysteine engineered antibody from the cell culture.
In other embodiments, the invention provides isolated anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), chimeric cysteine engineered antibodies comprising any of the herein described cysteine engineered antibody fused to a heterologous (non-TAHO, such as non-human CD79b (TAHO5) or non-cyno CD79b (TAHO40)) polypeptide. Examples of such chimeric molecules comprise any of the herein described cysteine engineered antibodies fused to a heterologous polypeptide such as, for example, an epitope tag sequence or a Fc region of an immunoglobulin.
The cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, may be a monoclonal antibody, antibody fragment, chimeric antibody, humanized antibody, single-chain antibody or antibody that competitively inhibits the binding of an anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), polypeptide antibody to its respective antigenic epitope. Antibodies of the present invention may optionally be conjugated to a growth inhibitory agent or cytotoxic agent such as a toxin, including, for example, an auristatin, an antibiotic, a radioactive isotope, a nucleolytic enzyme, or the like. The antibodies of the present invention may optionally be produced in CHO cells or bacterial cells and preferably inhibit the growth or proliferation of or induce the death of a cell to which they bind. For diagnostic purposes, the antibodies of the present invention may be detectably labeled, attached to a solid support, or the like.
Cysteine engineered antibodies may be useful in the treatment of cancer and include antibodies specific for cell surface and transmembrane receptors, and tumor-associated antigens (TAA). Such antibodies may be used as naked antibodies (unconjugated to a drug or label moiety) or as antibody-drug conjugates (ADC). Cysteine engineered antibodies of the invention may be site-specifically and efficiently coupled with a thiol-reactive reagent. The thiol-reactive reagent may be a multifunctional linker reagent, a capture label reagent, a fluorophore reagent, or a drug-linker intermediate. The cysteine engineered antibody may be labeled with a detectable label, immobilized on a solid phase support and/or conjugated with a drug moiety. Thiol reactivity may be generalized to any antibody where substitution of amino acids with reactive cysteine amino acids may be made within the ranges in the light chain selected from amino acid ranges: L10-L20, L105-L115, L109-L119, L116-L126, L122-L132, L163-L173, L200-L210; and within the ranges in the heavy chain selected from amino acid ranges: H1-H10, H18-H28, H79-H89, H107-H117, H109-H119, H111-H121, and in the Fc region within the ranges selected from H270-H280, H366-H376, H391-401, where the numbering of amino acid positions begins at position 1 of the Kabat numbering system (Kabat et al. (1991) Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md.) and continues sequentially thereafter as disclosed in WO2006034488; US 2007/0092940. Thiol reactivity may also be generalized to certain domains of an antibody, such as the light chain constant domain (CL) and heavy chain constant domains, CH1, CH2 and CH3. Cysteine replacements resulting in thiol reactivity values of 0.6 and higher may be made in the heavy chain constant domains α, δ, ε, γ, and μ of intact antibodies: IgA, IgD, IgE, IgG, and IgM, respectively, including the IgG subclasses: IgG1, IgG2, IgG3, IgG4, IgA, and IgA2. Such antibodies and their uses are disclosed in WO2006/034488; US 2007/0092940.
Cysteine engineered antibodies of the invention preferably retain the antigen binding capability of their wild type, parent antibody counterparts. Thus, cysteine engineered antibodies are capable of binding, preferably specifically, to antigens. Such antigens include, for example, tumor-associated antigens (TAA), cell surface receptor proteins and other cell surface molecules, transmembrane proteins, signalling proteins, cell survival regulatory factors, cell proliferation regulatory factors, molecules associated with (for e.g., known or suspected to contribute functionally to) tissue development or differentiation, lymphokines, cytokines, molecules involved in cell cycle regulation, molecules involved in vasculogenesis and molecules associated with (for e.g., known or suspected to contribute functionally to) angiogenesis. The tumor-associated antigen may be a cluster differentiation factor (i.e., a CD protein, including but not limited to a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40)). Cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibodies of the invention retain the antigen binding apability of their parent anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody counterparts. Thus, cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibodies of the invention are capable of binding, preferably specifically, to TAHO, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40), antigens including human anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), isoforms beta and/or alpha, including when such antigens are expressed on the surface of cells, including, without limitation, B cells.
In one aspect, antibodies of the invention may be conjugated with any label moiety which can be covalently attached to the antibody through a reactive moiety, an activated moiety, or a reactive cysteine thiol group (Singh et al (2002) Anal. Biochem. 304:147-15; Harlow E. and Lane, D. (1999) Using Antibodies: A Laboratory Manual, Cold Springs Harbor Laboratory Press, Cold Spring Harbor, N.Y.; Lundblad R. L. (1991) Chemical Reagents for Protein Modification, 2nd ed. CRC Press, Boca Raton, Fla.). The attached label may function to: (i) provide a detectable signal; (ii) interact with a second label to modify the detectable signal provided by the first or second label, e.g. to give FRET (fluorescence resonance energy transfer); (iii) stabilize interactions or increase affinity of binding, with antigen or ligand; (iv) affect mobility, e.g. electrophoretic mobility or cell-permeability, by charge, hydrophobicity, shape, or other physical parameters, or (v) provide a capture moiety, to modulate ligand affinity, antibody/antigen binding, or ionic complexation.
Labelled cysteine engineered antibodies may be useful in diagnostic assays, e.g., for detecting expression of an antigen of interest in specific cells, tissues, or serum. For diagnostic applications, the antibody will typically be labeled with a detectable moiety. Numerous labels are available which can be generally grouped into the following categories:
Radioisotopes (radionuclides), such as 3H, 11C, 14C, 18F, 32P, 35S, 64Cu, 68Ga, 86Y, 99Tc, 111In, 123I, 124I, 125I, 131I, 133Xe, 177Lu, 211At, or 213Bi. Radioisotope labelled antibodies are useful in receptor targeted imaging experiments. The antibody can be labeled with ligand reagents that bind, chelate or otherwise complex a radioisotope metal where the reagent is reactive with the engineered cysteine thiol of the antibody, using the techniques described in Current Protocols in Immunology, Volumes 1 and 2, Coligen et al, Ed. Wiley-Interscience, New York, N.Y., Pubs. (1991). Chelating ligands which may complex a metal ion include DOTA, DOTP, DOTMA, DTPA and TETA (Macrocyclics, Dallas, Tex.). Radionuclides can be targeted via complexation with the antibody-drug conjugates of the invention (Wu et al (2005) Nature Biotechnology 23(9):1137-1146).
Linker reagents such as DOTA-maleimide (4-maleimidobutyramidobenzyl-DOTA) can be prepared by the reaction of aminobenzyl-DOTA with 4-maleimidobutyric acid (Fluka) activated with isopropylchloroformate (Aldrich), following the procedure of Axworthy et al (2000) Proc. Natl. Acad. Sci. USA 97(4):1802-1807). DOTA-maleimide reagents react with the free cysteine amino acids of the cysteine engineered antibodies and provide a metal complexing ligand on the antibody (Lewis et al (1998) Bioconj. Chem. 9:72-86). Chelating linker labelling reagents such as DOTA-NHS (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid mono (N-hydroxysuccinimide ester) are commercially available (Macrocyclics, Dallas, Tex.). Receptor target imaging with radionuclide labelled antibodies can provide a marker of pathway activation by detection and quantitation of progressive accumulation of antibodies in tumor tissue (Albert et al (1998) Bioorg. Med. Chem. Lett. 8:1207-1210). The conjugated radio-metals may remain intracellular following lysosomal degradation.
Metal-chelate complexes suitable as antibody labels for imaging experiments are disclosed: U.S. Pat. No. 5,342,606; U.S. Pat. No. 5,428,155; U.S. Pat. No. 5,316,757; U.S. Pat. No. 5,480,990; U.S. Pat. No. 5,462,725; U.S. Pat. No. 5,428,139; U.S. Pat. No. 5,385,893; U.S. Pat. No. 5,739,294; U.S. Pat. No. 5,750,660; U.S. Pat. No. 5,834,456; Hnatowich et al (1983) J. Immunol. Methods 65:147-157; Meares et al (i984) Anal. Biochem. 142:68-78; Mirzadeh et al (1990) Bioconjugate Chem. 1:59-65; Meares et al (1990) J. Cancer 1990, Suppl. 10:21-26; Izard et al (1992) Bioconjugate Chem. 3:346-350; Nikula et al (1995) Nucl. Med. Biol. 22:387-90; Camera et al (1993) Nucl. Med. Biol. 20:955-62; Kukis et al (1998) J. Nucl. Med. 39:2105-2110; Verel et al (2003) J. Nucl. Med. 44:1663-1670; Camera et al (1994) J. Nucl. Med. 21:640-646; Ruegg et al (1990) Cancer Res. 50:4221-4226; Verel et al (2003) J. Nucl. Med. 44:1663-1670; Lee et al (2001) Cancer Res. 61:4474-4482; Mitchell, et al (2003) J. Nucl. Med. 44:1105-1112; Kobayashi et al (1999) Bioconjugate Chem. 10:103-111; Miederer et al (2004) J. Nucl. Med. 45:129-137; DeNardo et al (1998) Clinical Cancer Research 4:2483-90; Blend et al (2003) Cancer Biotherapy & Radiopharmaceuticals 18:355-363; Nikula et al (1999) J. Nucl. Med. 40:166-76; Kobayashi et al (1998) J. Nucl. Med. 39:829-36; Mardirossian et al (1993) Nucl. Med. Biol. 20:65-74; Roselli et al (1999) Cancer Biotherapy & Radiopharmaceuticals, 14:209-20.
Fluorescent labels such as rare earth chelates (europium chelates), fluorescein types including FITC, 5-carboxyfluorescein, 6-carboxy fluorescein; rhodamine types including TAMRA; dansyl; Lissamine; cyanines; phycoerythrins; Texas Red; and analogs thereof. The fluorescent labels can be conjugated to antibodies using the techniques disclosed in Current Protocols in Immunology, supra, for example. Fluorescent dyes and fluorescent label reagents include those which are commercially available from Invitrogen/Molecular Probes (Eugene, Oreg.) and Pierce Biotechnology, Inc. (Rockford, Ill.).
Various enzyme-substrate labels are available or disclosed (U.S. Pat. No. 4,275,149). The enzyme generally catalyzes a chemical alteration of a chromogenic substrate that can be measured using various techniques. For example, the enzyme may catalyze a color change in a substrate, which can be measured spectrophotometrically. Alternatively, the enzyme may alter the fluorescence or chemiluminescence of the substrate. Techniques for quantifying a change in fluorescence are described above. The chemiluminescent substrate becomes electronically excited by a chemical reaction and may then emit light which can be measured (using a chemiluminometer, for example) or donates energy to a fluorescent acceptor. Examples of enzymatic labels include luciferases (e.g., firefly luciferase and bacterial luciferase; U.S. Pat. No. 4,737,456), luciferin, 2,3-dihydrophthalazinediones, malate dehydrogenase, urease, peroxidase such as horseradish peroxidase (HRP), alkaline phosphatase (AP), β-galactosidase, glucoamylase, lysozyme, saccharide oxidases (e.g., glucose oxidase, galactose oxidase, and glucose-6-phosphate dehydrogenase), heterocyclic oxidases (such as uricase and xanthine oxidase), lactoperoxidase, microperoxidase, and the like. Techniques for conjugating enzymes to antibodies are described in O'Sullivan et al (1981) “Methods for the Preparation of Enzyme-Antibody Conjugates for use in Enzyme Immunoassay”, in Methods in Enzym. (ed J. Langone & H. Van Vunakis), Academic Press, New York, 73:147-166.
Examples of enzyme-substrate combinations include, for example:
(i) Horseradish peroxidase (HRP) with hydrogen peroxidase as a substrate, wherein the hydrogen peroxidase oxidizes a dye precursor (e.g., orthophenylene diamine (OPD) or 3,3′,5,5′-tetramethylbenzidine hydrochloride (TMB));
(ii) alkaline phosphatase (AP) with para-nitrophenyl phosphate as chromogenic substrate; and
(iii) β-D-galactosidase (β-D-Gal) with a chromogenic substrate (e.g., p-nitrophenyl-β-D-galactosidase) or fluorogenic substrate 4-methylumbelliferyl-β-D-galactosidase.
Numerous other enzyme-substrate combinations are available to those skilled in the art. For a general review, see U.S. Pat. No. 4,275,149 and U.S. Pat. No. 4,318,980.
A label may be indirectly conjugated with an amino acid side chain, an activated amino acid side chain, a cysteine engineered antibody, and the like. For example, the antibody can be conjugated with biotin and any of the three broad categories of labels mentioned above can be conjugated with avidin or streptavidin, or vice versa. Biotin binds selectively to streptavidin and thus, the label can be conjugated with the antibody in this indirect manner. Alternatively, to achieve indirect conjugation of the label with the polypeptide variant, the polypeptide variant is conjugated with a small hapten (e.g., digoxin) and one of the different types of labels mentioned above is conjugated with an anti-hapten polypeptide variant (e.g., anti-digoxin antibody). Thus, indirect conjugation of the label with the polypeptide variant can be achieved (Hermanson, G. (1996) in Bioconjugate Techniques Academic Press, San Diego).
The antibody of the present invention may be employed in any known assay method, such as ELISA, competitive binding assays, direct and indirect sandwich assays, and immunoprecipitation assays (Zola, (1987) Monoclonal Antibodies: A Manual of Techniques, pp. 147-158, CRC Press, Inc.).
A detection label may be useful for localizing, visualizing, and quantitating a binding or recognition event. The labelled antibodies of the invention can detect cell-surface receptors. Another use for detectably labelled antibodies is a method of bead-based immunocapture comprising conjugating a bead with a fluorescent labelled antibody and detecting a fluorescence signal upon binding of a ligand. Similar binding detection methodologies utilize the surface plasmon resonance (SPR) effect to measure and detect antibody-antigen interactions.
Detection labels such as fluorescent dyes and chemiluminescent dyes (Briggs et al (1997) “Synthesis of Functionalised Fluorescent Dyes and Their Coupling to Amines and Amino Acids,” J. Chem. Soc., Perkin-Trans. 1:1051-1058) provide a detectable signal and are generally applicable for labelling antibodies, preferably with the following properties: (i) the labelled antibody should produce a very high signal with low background so that small quantities of antibodies can be sensitively detected in both cell-free and cell-based assays; and (ii) the labelled antibody should be photostable so that the fluorescent signal may be observed, monitored and recorded without significant photo bleaching. For applications involving cell surface binding of labelled antibody to membranes or cell surfaces, especially live cells, the labels preferably (iii) have good water-solubility to achieve effective conjugate concentration and detection sensitivity and (iv) are non-toxic to living cells so as not to disrupt the normal metabolic processes of the cells or cause premature cell death.
Direct quantification of cellular fluorescence intensity and enumeration of fluorescently labelled events, e.g. cell surface binding of peptide-dye conjugates may be conducted on an system (FMAT® 8100 HTS System, Applied Biosystems, Foster City, Calif.) that automates mix-and-read, non-radioactive assays with live cells or beads (Miraglia, “Homogeneous cell- and bead-based assays for high throughput screening using fluorometric microvolume assay technology”, (1999) J. of Biomolecular Screening 4:193-204). Uses of labelled antibodies also include cell surface receptor binding assays, immunocapture assays, fluorescence linked immunosorbent assays (FLISA), caspase-cleavage (Zheng, “Caspase-3 controls both cytoplasmic and nuclear events associated with Fas-mediated apoptosis in vivo”, (1998) Proc. Natl. Acad. Sci. USA 95:618-23; U.S. Pat. No. 6,372,907), apoptosis (Vermes, “A novel assay for apoptosis. Flow cytometric detection of phosphatidylserine expression on early apoptotic cells using fluorescein labelled Annexin V” (1995) J. Immunol. Methods 184:39-51) and cytotoxicity assays. Fluorometric microvolume assay technology can be used to identify the up or down regulation by a molecule that is targeted to the cell surface (Swartzman, “A homogeneous and multiplexed immunoassay for high-throughput screening using fluorometric microvolume assay technology”, (1999) Anal. Biochem. 271:143-51).
Labelled antibodies of the invention are useful as imaging biomarkers and probes by the various methods and techniques of biomedical and molecular imaging such as: (i) MRI (magnetic resonance imaging); (ii) MicroCT (computerized tomography); (iii) SPECT (single photon emission computed tomography); (iv) PET (positron emission tomography) Chen et al (2004) Bioconjugate Chem. 15:41-49; (v) bioluminescence; (vi) fluorescence; and (vii) ultrasound. Immunoscintigraphy is an imaging procedure in which antibodies labeled with radioactive substances are administered to an animal or human patient and a picture is taken of sites in the body where the antibody localizes (U.S. Pat. No. 6,528,624). Imaging biomarkers may be objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacological responses to a therapeutic intervention. Biomarkers may be of several types: Type 0 are natural history markers of a disease and correlate longitudinally with known clinical indices, e.g. MRI assessment of synovial inflammation in rheumatoid arthritis; Type I markers capture the effect of an intervention in accordance with a mechanism-of-action, even though the mechanism may not be associated with clinical outcome; Type II markers function as surrogate endpoints where the change in, or signal from, the biomarker predicts a clinical benefit to “validate” the targeted response, such as measured bone erosion in rheumatoid arthritis by CT. Imaging biomarkers thus can provide pharmacodynamic (PD) therapeutic information about: (i) expression of a target protein, (ii) binding of a therapeutic to the target protein, i.e. selectivity, and (iii) clearance and half-life pharmacokinetic data. Advantages of in vivo imaging biomarkers relative to lab-based biomarkers include: non-invasive treatment, quantifiable, whole body assessment, repetitive dosing and assessment, i.e. multiple time points, and potentially transferable effects from preclinical (small animal) to clinical (human) results. For some applications, bioimaging supplants or minimizes the number of animal experiments in preclinical studies.
Peptide labelling methods are well known. See Haugland, 2003, Molecular Probes Handbook of Fluorescent Probes and Research Chemicals, Molecular Probes, Inc.; Brinkley, 1992, Bioconjugate Chem. 3:2; Garman, (1997) Non-Radioactive Labelling: A Practical Approach, Academic Press, London; Means (1990) Bioconjugate Chem. 1:2; Glazer et al (1975) Chemical Modification of Proteins. Laboratory Techniques in Biochemistry and Molecular Biology (T. S. Work and E. Work, Eds.) American Elsevier Publishing Co., New York; Lundblad, R. L. and Noyes, C. M. (1984) Chemical Reagents for Protein Modification, Vols. I and II, CRC Press, New York; Pfleiderer, G. (1985) “Chemical Modification of Proteins”, Modern Methods in Protein Chemistry, H. Tschesche, Ed., Walter DeGryter, Berlin and New York; and Wong (1991) Chemistry of Protein Conjugation and Cross-linking, CRC Press, Boca Raton, Fla.); De Leon-Rodriguez et al (2004) Chem. Eur. J. 10:1149-1155; Lewis et al (2001) Bioconjugate Chem. 12:320-324; Li et al (2002) Bioconjugate Chem. 13:110-115; Mier et al (2005) Bioconjugate Chem. 16:240-237.
Peptides and proteins labelled with two moieties, a fluorescent reporter and quencher in sufficient proximity undergo fluorescence resonance energy transfer (FRET). Reporter groups are typically fluorescent dyes that are excited by light at a certain wavelength and transfer energy to an acceptor, or quencher, group, with the appropriate Stokes shift for emission at maximal brightness. Fluorescent dyes include molecules with extended aromaticity, such as fluorescein and rhodamine, and their derivatives. The fluorescent reporter may be partially or significantly quenched by the quencher moiety in an intact peptide. Upon cleavage of the peptide by a peptidase or protease, a detectable increase in fluorescence may be measured (Knight, C. (1995) “Fluorimetric Assays of Proteolytic Enzymes”, Methods in Enzymology, Academic Press, 248:18-34).
The labelled antibodies of the invention may also be used as an affinity purification agent. In this process, the labelled antibody is immobilized on a solid phase such a Sephadex resin or filter paper, using methods well known in the art. The immobilized antibody is contacted with a sample containing the antigen to be purified, and thereafter the support is washed with a suitable solvent that will remove substantially all the material in the sample except the antigen to be purified, which is bound to the immobilized polypeptide variant. Finally, the support is washed with another suitable solvent, such as glycine buffer, pH 5.0, that will release the antigen from the polypeptide variant.
Labelling reagents typically bear reactive functionality which may react (i) directly with a cysteine thiol of a cysteine engineered antibody to form the labelled antibody, (ii) with a linker reagent to form a linker-label intermediate, or (iii) with a linker antibody to form the labelled antibody. Reactive functionality of labelling reagents include: maleimide, haloacetyl, iodoacetamide succinimidyl ester (e.g. NHS, N-hydroxysuccinimide), isothiocyanate, sulfonyl chloride, 2,6-dichlorotriazinyl, pentafluorophenyl ester, and phosphoramidite, although other functional groups can also be used.
An exemplary reactive functional group is N-hydroxysuccinimidyl ester (NHS) of a carboxyl group substituent of a detectable label, e.g. biotin or a fluorescent dye. The NHS ester of the label may be preformed, isolated, purified, and/or characterized, or it may be formed in situ and reacted with a nucleophilic group of an antibody. Typically, the carboxyl form of the label is activated by reacting with some combination of a carbodimide reagent, e.g. dicyclohexylcarbodiimide, diisopropylcarbodiimide, or a uronium reagent, e.g. TSTU (O—(N-Succinimidyl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate, HBTU (O-benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate), or HATU (O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate), an activator, such as 1-hydroxybenzotriazole (HOBt), and N-hydroxysuccinimide to give the NHS ester of the label. In some cases, the label and the antibody may be coupled by in situ activation of the label and reaction with the antibody to form the label-antibody conjugate in one step. Other activating and coupling reagents include TBTU (2-(1H-benzotriazo-1-yl)-1-1,3,3-tetramethyluronium hexafluorophosphate), TFFH (N,N′,N″,N′″-tetramethyluronium 2-fluoro-hexafluorophosphate), PyBOP (benzotriazole-1-yl-oxy-tris-pyrrolidino-phosphonium hexafluorophosphate, EEDQ (2-ethoxy-1-ethoxycarbonyl-1,2-dihydro-quinoline), DCC (dicyclohexylcarbodiimide); DIPCDI (diisopropylcarbodiimide), MSNT (1-(mesitylene-2-sulfonyl)-3-nitro-1H-1,2,4-triazole, and aryl sulfonyl halides, e.g. triisopropylbenzenesulfonyl chloride.
Albumin Binding Peptide-Fab Compounds of the Invention:
In one aspect, the antibody of the invention is fused to an albumin binding protein. Plasma-protein binding can be an effective means of improving the pharmacokinetic properties of short lived molecules. Albumin is the most abundant protein in plasma. Serum albumin binding peptides (ABP) can alter the pharmacodynamics of fused active domain proteins, including alteration of tissue uptake, penetration, and diffusion. These pharmacodynamic parameters can be modulated by specific selection of the appropriate serum albumin binding peptide sequence (US 20040001827). A series of albumin binding peptides were identified by phage display screening (Dennis et al. (2002) “Albumin Binding As A General Strategy For Improving The Pharmacokinetics Of Proteins” J Biol. Chem. 277:35035-35043; WO 01/45746). Compounds of the invention include ABP sequences taught by: (i) Dennis et al (2002) J Biol. Chem. 277:35035-35043 at Tables III and IV, page 35038; (ii) US 20040001827 at [0076] SEQ ID NOS: 9-22; and (iii) WO 01/45746 at pages 12-13, all of which are incorporated herein by reference. Albumin Binding (ABP)-Fabs are engineered by fusing an albumin binding peptide to the C-terminus of Fab heavy chain in 1:1 stoichiometric ratio (1 ABP/1 Fab). It was shown that association of these ABP-Fabs with albumin increased antibody half life by more than 25 fold in rabbits and mice. The above described reactive Cys residues can therefore be introduced in these ABP-Fabs and used for site-specific conjugation with cytotoxic drugs followed by in vivo animal studies.
Exemplary albumin binding peptide sequences include, but are not limited to the amino acid sequences listed in SEQ ID NOS: 52-56:
Antibody-Drug Conjugates
In another aspect, the invention provides immunoconjugates, or antibody-drug conjugates (ADC), comprising an antibody conjugated to a cytotoxic agent such as a chemotherapeutic agent, a drug, a growth inhibitory agent, a toxin (e.g., an enzymatically active toxin of bacterial, fungal, plant, or animal origin, or fragments thereof), or a radioactive isotope (i.e., a radioconjugate). In another aspect, the invention further provides methods of using the immunoconjugates. In one aspect, an immunoconjugate comprises any of the above anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibodies, covalently attached to a cytotoxic agent or a detectable agent.
In one embodiment, a TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40 antibody of the invention, binds to the same epitope on a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40), bound by another TAHO antibody, such as another anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody. In another embodiment, a TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), of the invention binds to the same epitope on a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40), bound by the Fab fragment of, SN8 monoclonal antibody generated from hybridomas obtained from Roswell Park Cancer Institute (Okazaki et al., Blood, 81(1): 84-95 (1993), monoclonal antibody comprising the variable domains of SEQ ID NO: 10 (
In another embodiment, a TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody of the invention binds to an epitope on a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40), distinct from an epitope bound by another TAHO antibody, such as anti-human CD79b (TAHO5) or anti-CD79b (TAHO40) antibody. In another embodiment, a TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody of the invention binds to an epitope on a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40), distinct from an epitope bound by the Fab fragment of, SN8 monoclonal antibody generated from hybridomas obtained from Roswell Park Cancer Institute (Okazaki et al., Blood, 81(1): 84-95 (1993), monoclonal antibody comprising the variable domains of SEQ ID NO: 10 (
In another embodiment, a TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody of the invention is distinct from (i.e., it is not) a Fab fragment of, the monoclonal antibody generated from hybridomas obtained from Roswell Park Cancer Institute (Okazaki et al., Blood, 81(1): 84-95 (1993), the monoclonal antibody comprising the variable domains of SEQ ID NO: 10 (
In one embodiment, an antibody of the invention specifically binds to CD79b of a first animal species, and does not specifically bind to CD79b of a second animal species. In one embodiment, the first animal species is human and/or primate (e.g., cynomolgus monkey), and the second animal species is murine (e.g., mouse) and/or canine. In one embodiment, the first animal species is human. In one embodiment, the first animal species is primate, for example cynomolgus monkey. In one embodiment, the second animal species is murine, for example mouse. In one embodiment, the second animal species is canine.
In other embodiments of the present invention, the invention provides vectors comprising DNA encoding any of the herein described antibodies, including cysteine-engineered antibodies. Host cell comprising any such vector are also provided. By way of example, the host cells may be CHO cells, E. coli cells, or yeast cells. A process for producing any of the herein described antibodies is further provided and comprises culturing host cells under conditions suitable for expression of the desired antibody and recovering the desired antibody from the cell culture.
In another embodiment, the invention provides oligopeptides (“TAHO binding oligopeptides”, such as “human CD79b (TAHO5) binding oligopeptides” or “cyno CD79b (TAHO40) binding oligopeptides”) which bind, preferably specifically, to any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides. Optionally, the TAHO binding oligopeptides, such as human CD79b (TAHO5) binding oligopeptides or cyno CD79b (TAHO40) binding oligopeptides, of the present invention may be conjugated to a growth inhibitory agent or cytotoxic agent such as a toxin, including, for example, a maytansinoid, dolostatin derivative or calicheamicin, an antibiotic, a radioactive isotope, a nucleolytic enzyme, or the like. The TAHO binding oligopeptides, such as human CD79b (TAHO5) binding oligopeptides or cyno CD79b (TAHO40) binding oligopeptides, of the present invention may optionally be produced in CHO cells or bacterial cells and preferably induce death of a cell to which they bind. For detection purposes, the TAHO binding oligopeptides, such as human CD79b (TAHO5) binding oligopeptides or cyno CD79b (TAHO40) binding oligopeptides, of the present invention may be detectably labeled, attached to a solid support, or the like.
In other embodiments of the present invention, the invention provides vectors comprising DNA encoding any of the herein described TAHO binding oligopeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding oligopeptides. Host cell comprising any such vector are also provided. By way of example, the host cells may be CHO cells, E. coli cells, or yeast cells. A process for producing any of the herein described TAHO binding oligopeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding oligopeptides, is further provided and comprises culturing host cells under conditions suitable for expression of the desired oligopeptide and recovering the desired oligopeptide from the cell culture.
In another embodiment, the invention provides small organic molecules (“TAHO binding organic molecules”, such as “human CD79b (TAHO5) binding organic molecules” or “cyno CD79b (TAHO40) binding organic molecules”) which bind, preferably specifically, to any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptides. Optionally, the TAHO binding organic molecules, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding organic molecules, of the present invention may be conjugated to a growth inhibitory agent or cytotoxic agent such as a toxin, including, for example, a maytansinoid, dolastatin derivative or calicheamicin, an antibiotic, a radioactive isotope, a nucleolytic enzyme, or the like. The TAHO binding organic molecules, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding organic molecules, of the present invention preferably induce death of a cell to which they bind. For detection purposes, the TAHO binding organic molecules, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding organic molecules, of the present invention may be detectably labeled, attached to a solid support, or the like.
In a still further embodiment, the invention concerns a composition of matter comprising a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40) polypeptide, as described herein, a chimeric TAHO polypeptide, such as chimeric human CD79b (TAHO5) or cyno CD79b (TAHO40) polypeptide, as described herein, an anti-TAHO antibody as described herein, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, a TAHO binding oligopeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding oligopeptide, as described herein, or a TAHO binding organic molecule, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding organic molecule, as described herein, in combination with a carrier. Optionally, the carrier is a pharmaceutically acceptable carrier.
In yet another embodiment, the invention concerns an article of manufacture comprising a container and a composition of matter contained within the container, wherein the composition of matter may comprise a TAHO polypeptide such as human CD79b (TAHO5) or cyno CD79b (TAHO40) polypeptide, as described herein, a chimeric TAHO polypeptide, such as chimeric human CD79b (TAHO5) or cyno CD79b (TAHO40) polypeptide, as described herein, an anti-TAHO antibody as described herein, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, a TAHO binding oligopeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding oligopeptide, as described herein, or a TAHO binding organic molecule, such as TAHO binding organic molecule, as described herein. The article may further optionally comprise a label affixed to the container, or a package insert included with the container, that refers to the use of the composition of matter for the therapeutic treatment.
In one aspect, the invention provides a kit comprising a first container comprising a composition comprising one or more TAHO antibodies, such as an anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, of the invention; and a second container comprising a buffer. In one embodiment, the buffer is pharmaceutically acceptable. In one embodiment, a composition comprising an antagonist antibody further comprises a carrier, which in some embodiments is pharmaceutically acceptable. In one embodiment, a kit further comprises instructions for administering the composition (e.g., the antibody) to a subject.
Another embodiment of the present invention is directed to the use of a TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) polypeptide, as described herein, a chimeric TAHO polypeptide, such as chimeric human CD79b (TAHO5) or cyno CD79b (TAHO40) polypeptide, as described herein, an anti-TAHO polypeptide antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, as described herein, a TAHO binding oligopeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding oligopeptide, as described herein, or a TAHO binding organic molecule, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding organic molecule, as described herein, for the preparation of a medicament useful in the treatment of a condition which is responsive to the TAHO polypeptide, such as CD79 polypeptide, chimeric TAHO polypeptide, such as chimeric human CD79b (TAHO5) or cyno CD79b (TAHO40) polypeptide, anti-TAHO polypeptide antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, TAHO binding oligopeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding oligopeptide, or TAHO binding organic molecule, such as human CD79b (TAHO5) or cyno CD79b (TAHO40) binding organic molecule.
In one aspect, the invention provides use of a TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as a cancer, a tumor and/or a cell proliferative disorder. In one embodiment, cancer, tumor and/or cell proliferative disorder is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In one aspect, the invention provides use of a nucleic acid of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as a cancer, a tumor and/or a cell proliferative disorder. In one embodiment, cancer, tumor and/or cell proliferative disorder is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In one aspect, the invention provides use of an expression vector of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as a cancer, a tumor and/or a cell proliferative disorder. In one embodiment, cancer, tumor and/or cell proliferative disorder is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In one aspect, the invention provides use of a host cell of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as a cancer, a tumor and/or a cell proliferative disorder. In one embodiment, cancer, tumor and/or cell proliferative disorder is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In one aspect, the invention provides use of an article of manufacture of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as a cancer, a tumor and/or a cell proliferative disorder. In one embodiment, cancer, tumor and/or cell proliferative disorder is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In one aspect, the invention provides use of a kit of the invention in the preparation of a medicament for the therapeutic and/or prophylactic treatment of a disease, such as a cancer, a tumor and/or a cell proliferative disorder. In one embodiment, cancer, tumor and/or cell proliferative disorder is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In one aspect, the invention provides a method of inhibiting the growth of a cell that expresses any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), said method comprising contacting said cell with an antibody of the invention thereby causing an inhibition of growth of said cell. In one embodiment, the antibody is conjugated to a cytotoxic agent. In one embodiment, the antibody is conjugated to a growth inhibitory agent.
In one aspect, the invention provides a method of therapeutically treating a mammal having a cancerous tumor comprising a cell that expresses any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), said method comprising administering to said mammal a therapeutically effective amount of an antibody of the invention, thereby effectively treating said mammal. In one embodiment, the antibody is conjugated to a cytotoxic agent. In one embodiment, the antibody is conjugated to a growth inhibitory agent.
In one aspect, the invention provides a method for treating or preventing a cell proliferative disorder associated with increased expression of any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), said method comprising administering to a subject in need of such treatment an effective amount of an antibody of the invention, thereby effectively treating or preventing said cell proliferative disorder. In one embodiment, said proliferative disorder is cancer. In one embodiment, the antibody is conjugated to a cytotoxic agent. In one embodiment, the antibody is conjugated to a growth inhibitory agent.
In one aspect, the invention provides a method for inhibiting the growth of a cell, wherein growth of said cell is at least in part dependent upon a growth potentiating effect of any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), said method comprising contacting said cell with an effective amount of an antibody of the invention, thereby inhibiting the growth of said cell. In one embodiment, the antibody is conjugated to a cytotoxic agent. In one embodiment, the antibody is conjugated to a growth inhibitory agent.
A method of therapeutically treating a tumor in a mammal, wherein the growth of said tumor is at least in part dependent upon a growth potentiating effect of any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), said method comprising contacting said cell with an effective amount of an antibody of the invention, thereby effectively treating said tumor. In one embodiment, the antibody is conjugated to a cytotoxic agent. In one embodiment, the antibody is conjugated to a growth inhibitory agent.
A method of treating cancer comprising administering to a patient the pharmaceutical formulation comprising an immunoconjugate described herein, acceptable diluent, carrier or excipient. In one embodiment, the cancer is selected from the lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL) and mantle cell lymphoma. In one embodiment, the patient is administered a cytotoxic agent in combination with the antibody-drug conjugate compound.
A method of inhibiting B cell proliferation comprising exposing a cell to an immunoconjugate comprising an antibody of the invention under conditions permissive for binding of the immunoconjugate to a TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40). In one embodiment, the B cell proliferation is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL) and mantle cell lymphoma. In one embodiment, the B cell is a xenograft. In one embodiment, the exposing takes place in vitro. In one embodiment, the exposing taxes place in vivo.
A method of determining the presence of any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), in a sample suspected of containing any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), said method comprising exposing said sample to an antibody of the invention, and determining binding of said antibody to any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), in said sample wherein binding of said antibody to any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), in said sample is indicative of the presence of said protein in said sample. In one embodiment, the sample is a biological sample. In a further embodiment, the biological sample comprises B cells. In one embodiment, the biological sample is from a mammal experiencing or suspected of experiencing a B cell disorder and/or a B cell proliferative disorder including, but not limited to, lymphoma, non-Hodgkin's lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL) and mantle cell lymphoma.
In one aspect, a method of diagnosing a cell proliferative disorder associated with an increase in cells, such as B cells, expressing any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), is provided, the method comprising contacting a test cells in a biological sample with any of the above antibodies; determining the level of antibody bound to test cells in the sample by detecting binding of the antibody to a TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40); and comparing the level of antibody bound to cells in a control sample, wherein the level of antibody bound is normalized to the number of TAHO-expressing cells, such as human CD79b (TAHO5) or cyno CD79b (TAHO40)-expressing cells, in the test and control samples, and wherein a higher level of antibody bound in the test sample as compared to the control sample indicates the presence of a cell proliferative disorder associated with cells expressing any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40).
In one aspect, a method of detecting soluble any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), in blood or serum, the method comprising contacting a test sample of blood or serum from a mammal suspected of experiencing a B cell proliferative disorder with an anti-TAHO antibody, including anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, of the invention and detecting a increase in soluble any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), in the test sample relative to a control sample of blood or serum from a normal mammal. In an embodiment, the method of detecting is useful as a method of diagnosing a B cell proliferative disorder associated with an increase in soluble any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), in blood or serum of a mammal.
A method of binding an antibody, oligopeptide or organic molecule of the invention to a cell that expresses any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), said method comprising contacting said cell with an antibody of the invention. In one embodiment, the antibody is conjugated to a cytotoxic agent. In one embodiment, the antibody is conjugated to a growth inhibitory agent.
Methods of the invention can be used to affect any suitable pathological state, for example, cells and/or tissues associated with expression of any of the above or below described TAHO polypeptides, such as human CD79b (TAHO5) or cyno CD79b (TAHO40). In one embodiment, a cell that is targeted in a method of the invention is a hematopoietic cell. For example, a hematopoietic cell can be one selected from the group consisting of a lymphocyte, leukocyte, platelet, erythrocyte and natural killer cell. In one embodiment, a cell that is targeted in a method of the invention is a B cell or T cell. In one embodiment, a cell that is targeted in a method of the invention is a cancer cell. For example, a cancer cell can be one selected from the group consisting of a lymphoma cell, leukemia cell, or myeloma cell.
Methods of the invention can further comprise additional treatment steps. For example, in one embodiment, a method further comprises a step wherein a targeted cell and/or tissue (e.g., a cancer cell) is exposed to radiation treatment or a chemotherapeutic agent.
As described herein, CD79b is a signaling component of the B cell receptor. Accordingly, in one embodiment of methods of the invention, a cell that is targeted (e.g., a cancer cell) is one in which a TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), is expressed as compared to a cell that does not express a TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40). In a further embodiment, the targeted cell is a cancer cell in which a TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), expression is enhanced as compared to a normal non-cancer cell of the same tissue type. In one embodiment, a method of the invention causes the death of a targeted cell.
Another embodiment of the present invention is directed to the use of an anti-TAHO polypeptide antibody, including anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody, as described herein, for the preparation of a medicament useful in the treatment of a condition which is responsive to the anti-TAHO polypeptide antibody, including anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibody.
Another aspect of the invention provides a method of using an anti-cyno CD79b (TAHO40) antibody or a cysteine engineered anti-cyno CD79b (TAHO40) antibody, or an ADC comprising an anti-cyno CD79b antibody or a cysteine engineered anti-cyno CD79b (TAHO40) antibody, as described herein, to test the safety of therapeutically treating a mammal having a cancerous tumor wherein said treatment comprises the administration of an anti-human CD79b (TAHO5) antibody or a cysteine engineered anti-human CD79b (TAHO5) antibody, or an ADC comprising an anti-human CD79b (TAHO5) antibody or a cysteine engineered anti-human CD79b (TAHO5) antibody, as described herein.
Another aspect of the invention is a composition comprising a mixture of antibody-drug compounds of Formula I where the average drug loading per antibody is about 2 to about 5, or about 3 to about 4.
Another aspect of the invention is a pharmaceutical composition including a Formula I ADC compound, a mixture of Formula I ADC compounds, or a pharmaceutically acceptable salt or solvate thereof, and a pharmaceutically acceptable diluent, carrier, or excipient.
Another aspect provides a pharmaceutical combination comprising a Formula I ADC compound and a second compound having anticancer properties or other therapeutic effects.
Another aspect is a method for killing or inhibiting the proliferation of tumor cells or cancer cells comprising treating the cells with an amount of an antibody-drug conjugate of Formula I, or a pharmaceutically acceptable salt or solvate thereof, being effective to kill or inhibit the proliferation of the tumor cells or cancer cells.
Another aspect is methods of treating cancer comprising administering to a patient a therapeutically effective amount of a pharmaceutical composition including a Formula I ADC.
Another aspect includes articles of manufacture, i.e. kits, comprising an antibody-drug conjugate, a container, and a package insert or label indicating a treatment.
The terms “TAHO polypeptide” and “TAHO” as used herein and when immediately followed by a numerical designation, refer to various polypeptides, wherein the complete designation (i.e., TAHO/number) refers to specific polypeptide sequences as described herein. The terms “TAHO/number polypeptide” and “TAHO/number” wherein the term “number” is provided as an actual numerical designation as used herein encompass native sequence polypeptides, polypeptide variants and fragments of native sequence polypeptides and polypeptide variants (which are further defined herein). The TAHO polypeptides described herein may be isolated from a variety of sources, such as from human tissue types or from another source, or prepared by recombinant or synthetic methods. The term “TAHO polypeptide” refers to each individual TAHO/number polypeptide disclosed herein. All disclosures in this specification which refer to the “TAHO polypeptide” refer to each of the polypeptides individually as well as jointly. For example, descriptions of the preparation of, purification of, derivation of, formation of antibodies to or against, formation of TAHO binding oligopeptides to or against, formation of TAHO binding organic molecules to or against, administration of, compositions containing, treatment of a disease with, etc., pertain to each polypeptide of the invention individually.
“TAHO4” is also herein referred to as “human CD79a”. “TAHO5” is also herein referred to as “human CD79b”. “TAHO39” is also herein referred to as “cyno CD79a” or “cynomolgus CD79a”. “TAHO40” is also herein referred to as “cyno CD79b” or “cynomolgus CD79b”. “Cynomolgus” is also referred herein to as “cyno”.
The term “CD79b”, as used herein, refers to any native CD79b from any vertebrate source, including mammals such as primates (e.g. humans, cynomolgus monkey (cyno)) and rodents (e.g., mice and rats), unless otherwise indicated. Human CD79b is also referred herein to as “PRO36249” (SEQ ID NO: 2) or “TAHO5” and encoded by the nucleotide sequence (SEQ ID NO: 1) also referred herein to as “DNA225786”. Cynomologus CD79b is also referred herein to as “cyno CD79b” or “PRO283627” (SEQ ID NO: 239) or “TAHO40” and encoded by the nucleotide sequence (SEQ ID NO: 238) also referred herein to as “DNA548455”. The term “CD79b” encompasses “full-length,” unprocessed CD79b as well as any form of CD79b that results from processing in the cell. The term also encompasses naturally occurring variants of CD79b, e.g., splice variants, allelic variants and isoforms. The CD79b polypeptides described herein may be isolated from a variety of sources, such as from human tissue types or from another source, or prepared by recombinant or synthetic methods. A “native sequence TAHO polypeptide” comprises a polypeptide having the same amino acid sequence as the corresponding TAHO polypeptide derived from nature. Such native sequence TAHO polypeptides can be isolated from nature or can be produced by recombinant or synthetic means. The term “native sequence TAHO polypeptide” specifically encompasses naturally-occurring truncated or secreted forms of the specific TAHO polypeptide (e.g., an extracellular domain sequence), naturally-occurring variant forms (e.g., alternatively spliced forms) and naturally-occurring allelic variants of the polypeptide. In certain embodiments of the invention, the native sequence TAHO polypeptides disclosed herein are mature or full-length native sequence polypeptides comprising the full-length amino acids sequences shown in the accompanying figures. Start and stop codons (if indicated) are shown in bold font and underlined in the figures. Nucleic acid residues indicated as “N” in the accompanying figures are any nucleic acid residue. However, while the TAHO polypeptides disclosed in the accompanying figures are shown to begin with methionine residues designated herein as amino acid position 1 in the figures, it is conceivable and possible that other methionine residues located either upstream or downstream from the amino acid position 1 in the figures may be employed as the starting amino acid residue for the TAHO polypeptides.
A “B-cell surface marker” or “B-cell surface antigen” herein is an antigen expressed on the surface of a B cell that can be targeted with an antagonist that binds thereto, including but not limited to, antibodies to a B-cell surface antigen or a soluble form a B-cell surface antigen capable of antagonizing binding of a ligand to the naturally occurring B-cell antigen. Exemplary B-cell surface markers include the CD10, CD19, CD20, CD21, CD22, CD23, CD24, CD37, CD40, CD53, CD72, CD73, CD74, CDw75, CDw76, CD77, CDw78, CD79a, CD79b, CD80, CD81, CD82, CD83, CDw84, CD85 and CD86 leukocyte surface markers (for descriptions, see The Leukocyte Antigen Facts Book, 2nd Edition. 1997, ed. Barclay et al. Academic Press, Harcourt Brace & Co., New York). Other B-cell surface markers include RP105, FcRH2, B-cell CR2, CCR6, P2×5, HLA-DOB, CXCR5, FCER2, BR3, BAFF, BLyS, Btig, NAG14, SLGC16270, FcRH1, IRTA2, ATWD578, FcRH3, IRTA1, FcRH6, BCMA, and 239287. The B-cell surface marker of particular interest is preferentially expressed on B cells compared to other non-B-cell tissues of a mammal and may be expressed on both precursor B cells and mature B cells.
The TAHO polypeptide “extracellular domain” or “ECD” refers to a form of the TAHO polypeptide which is essentially free of the transmembrane and cytoplasmic domains. Ordinarily, a TAHO polypeptide ECD will have less than 1% of such transmembrane and/or cytoplasmic domains and preferably, will have less than 0.5% of such domains. It will be understood that any transmembrane domains identified for the TAHO polypeptides of the present invention are identified pursuant to criteria routinely employed in the art for identifying that type of hydrophobic domain. The exact boundaries of a transmembrane domain may vary but most likely by no more than about 5 amino acids at either end of the domain as initially identified herein. Optionally, therefore, an extracellular domain of a TAHO polypeptide may contain from about 5 or fewer amino acids on either side of the transmembrane domain/extracellular domain boundary as identified in the Examples or specification and such polypeptides, with or without the associated signal peptide, and nucleic acid encoding them, are contemplated by the present invention.
The approximate location of the “signal peptides” of the various TAHO polypeptides disclosed herein may be shown in the present specification and/or the accompanying figures. It is noted, however, that the C-terminal boundary of a signal peptide may vary, but most likely by no more than about 5 amino acids on either side of the signal peptide C-terminal boundary as initially identified herein, wherein the C-terminal boundary of the signal peptide may be identified pursuant to criteria routinely employed in the art for identifying that type of amino acid sequence element (e.g., Nielsen et al., Prot. Eng. 10:1-6 (1997) and von Heinje et al., Nucl. Acids. Res. 14:4683-4690 (1986)). Moreover, it is also recognized that, in some cases, cleavage of a signal sequence from a secreted polypeptide is not entirely uniform, resulting in more than one secreted species. These mature polypeptides, where the signal peptide is cleaved within no more than about 5 amino acids on either side of the C-terminal boundary of the signal peptide as identified herein, and the polynucleotides encoding them, are contemplated by the present invention.
“TAHO polypeptide variant” means a TAHO polypeptide, preferably an active TAHO polypeptide, as defined herein having at least about 80% amino acid sequence identity with a full-length native sequence TAHO polypeptide sequence as disclosed herein, a TAHO polypeptide sequence lacking the signal peptide as disclosed herein, an extracellular domain of a TAHO polypeptide, with or without the signal peptide, as disclosed herein or any other fragment of a full-length TAHO polypeptide sequence as disclosed herein (such as those encoded by a nucleic acid that represents only a portion of the complete coding sequence for a full-length TAHO polypeptide). Such TAHO polypeptide variants include, for instance, TAHO polypeptides wherein one or more amino acid residues are added, or deleted, at the N- or C-terminus of the full-length native amino acid sequence. Ordinarily, a TAHO polypeptide variant will have at least about 80% amino acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% amino acid sequence identity, to a full-length native sequence TAHO polypeptide sequence as disclosed herein, a TAHO polypeptide sequence lacking the signal peptide as disclosed herein, an extracellular domain of a TAHO polypeptide, with or without the signal peptide, as disclosed herein or any other specifically defined fragment of a full-length TAHO polypeptide sequence as disclosed herein. Ordinarily, TAHO variant polypeptides are at least about 10 amino acids in length, alternatively at least about 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600 amino acids in length, or more. Optionally, TAHO variant polypeptides will have no more than one conservative amino acid substitution as compared to the native TAHO polypeptide sequence, alternatively no more than 2, 3, 4, 5, 6, 7, 8, 9, or 10 conservative amino acid substitution as compared to the native TAHO polypeptide sequence.
“Percent (%) amino acid sequence identity” with respect to the TAHO polypeptide sequences identified herein is defined as the percentage of amino acid residues in a candidate sequence that are identical with the amino acid residues in the specific TAHO polypeptide sequence, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. Those skilled in the art can determine appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full length of the sequences being compared. For purposes herein, however, % amino acid sequence identity values are generated using the sequence comparison computer program ALIGN-2, wherein the complete source code for the ALIGN-2 program is provided in Table 1 below. The ALIGN-2 sequence comparison computer program was authored by Genentech, Inc. and the source code shown in Table 1 below has been filed with user documentation in the U.S. Copyright Office, Washington D.C., 20559, where it is registered under U.S. Copyright Registration No. TXU510087. The ALIGN-2 program is publicly available through Genentech, Inc., South San Francisco, Calif. or may be compiled from the source code provided in Table 1 below. The ALIGN-2 program should be compiled for use on a UNIX operating system, preferably digital UNIX V4.0D. All sequence comparison parameters are set by the ALIGN-2 program and do not vary.
In situations where ALIGN-2 is employed for amino acid sequence comparisons, the % amino acid sequence identity of a given amino acid sequence A to, with, or against a given amino acid sequence B (which can alternatively be phrased as a given amino acid sequence A that has or comprises a certain % amino acid sequence identity to, with, or against a given amino acid sequence B) is calculated as follows:
100 times the fraction X/Y
where X is the number of amino acid residues scored as identical matches by the sequence alignment program ALIGN-2 in that program's alignment of A and B, and where Y is the total number of amino acid residues in B. It will be appreciated that where the length of amino acid sequence A is not equal to the length of amino acid sequence B, the % amino acid sequence identity of A to B will not equal the % amino acid sequence identity of B to A. As examples of % amino acid sequence identity calculations using this method, Tables 2 and 3 demonstrate how to calculate the % amino acid sequence identity of the amino acid sequence designated “Comparison Protein” to the amino acid sequence designated “TAHO”, wherein “TAHO” represents the amino acid sequence of a hypothetical TAHO polypeptide of interest, “Comparison Protein” represents the amino acid sequence of a polypeptide against which the “TAHO” polypeptide of interest is being compared, and “X, “Y” and “Z” each represent different hypothetical amino acid residues. Unless specifically stated otherwise, all % amino acid sequence identity values used herein are obtained as described in the immediately preceding paragraph using the ALIGN-2 computer program.
“TAHO variant polynucleotide” or “TAHO variant nucleic acid sequence” means a nucleic acid molecule which encodes a TAHO polypeptide, preferably an active TAHO polypeptide, as defined herein and which has at least about 80% nucleic acid sequence identity with a nucleotide acid sequence encoding a full-length native sequence TAHO polypeptide sequence as disclosed herein, a full-length native sequence TAHO polypeptide sequence lacking the signal peptide as disclosed herein, an extracellular domain of a TAHO polypeptide, with or without the signal peptide, as disclosed herein or any other fragment of a full-length TAHO polypeptide sequence as disclosed herein (such as those encoded by a nucleic acid that represents only a portion of the complete coding sequence for a full-length TAHO polypeptide). Ordinarily, a TAHO variant polynucleotide will have at least about 80% nucleic acid sequence identity, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% nucleic acid sequence identity with a nucleic acid sequence encoding a full-length native sequence TAHO polypeptide sequence as disclosed herein, a full-length native sequence TAHO polypeptide sequence lacking the signal peptide as disclosed herein, an extracellular domain of a TAHO polypeptide, with or without the signal sequence, as disclosed herein or any other fragment of a full-length TAHO polypeptide sequence as disclosed herein. Variants do not encompass the native nucleotide sequence.
Ordinarily, TAHO variant polynucleotides are at least about 5 nucleotides in length, alternatively at least about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, or 1000 nucleotides in length, wherein in this context the term “about” means the referenced nucleotide sequence length plus or minus 10% of that referenced length.
“Percent (%) nucleic acid sequence identity” with respect to TAHO-encoding nucleic acid sequences identified herein is defined as the percentage of nucleotides in a candidate sequence that are identical with the nucleotides in the TAHO nucleic acid sequence of interest, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity. Alignment for purposes of determining percent nucleic acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. For purposes herein, however, % nucleic acid sequence identity values are generated using the sequence comparison computer program ALIGN-2, wherein the complete source code for the ALIGN-2 program is provided in Table 1 below. The ALIGN-2 sequence comparison computer program was authored by Genentech, Inc. and the source code shown in Table 1 below has been filed with user documentation in the U.S. Copyright Office, Washington D.C., 20559, where it is registered under U.S. Copyright Registration No. TXU510087. The ALIGN-2 program is publicly available through Genentech, Inc., South San Francisco, Calif. or may be compiled from the source code provided in Table 1 below. The ALIGN-2 program should be compiled for use on a UNIX operating system, preferably digital UNIX V4.0D. All sequence comparison parameters are set by the ALIGN-2 program and do not vary.
In situations where ALIGN-2 is employed for nucleic acid sequence comparisons, the % nucleic acid sequence identity of a given nucleic acid sequence C to, with, or against a given nucleic acid sequence D (which can alternatively be phrased as a given nucleic acid sequence C that has or comprises a certain % nucleic acid sequence identity to, with, or against a given nucleic acid sequence D) is calculated as follows:
100 times the fraction W/Z
where W is the number of nucleotides scored as identical matches by the sequence alignment program ALIGN-2 in that program's alignment of C and D, and where Z is the total number of nucleotides in D. It will be appreciated that where the length of nucleic acid sequence C is not equal to the length of nucleic acid sequence D, the % nucleic acid sequence identity of C to D will not equal the % nucleic acid sequence identity of D to C. As examples of % nucleic acid sequence identity calculations, Tables 4 and 5, demonstrate how to calculate the % nucleic acid sequence identity of the nucleic acid sequence designated “Comparison DNA” to the nucleic acid sequence designated “TAHO-DNA”, wherein “TAHO-DNA” represents a hypothetical TAHO-encoding nucleic acid sequence of interest, “Comparison DNA” represents the nucleotide sequence of a nucleic acid molecule against which the “TAHO-DNA” nucleic acid molecule of interest is being compared, and “N”, “L” and “V” each represent different hypothetical nucleotides. Unless specifically stated otherwise, all % nucleic acid sequence identity values used herein are obtained as described in the immediately preceding paragraph using the ALIGN-2 computer program.
In other embodiments, TAHO variant polynucleotides are nucleic acid molecules that encode a TAHO polypeptide and which are capable of hybridizing, preferably under stringent hybridization and wash conditions, to nucleotide sequences encoding a full-length TAHO polypeptide as disclosed herein. TAHO variant polypeptides may be those that are encoded by a TAHO variant polynucleotide.
The term “full-length coding region” when used in reference to a nucleic acid encoding a TAHO polypeptide refers to the sequence of nucleotides which encode the full-length TAHO polypeptide of the invention (which is often shown between start and stop codons, inclusive thereof, in the accompanying figures). The term “full-length coding region” when used in reference to an ATCC deposited nucleic acid refers to the TAHO polypeptide-encoding portion of the cDNA that is inserted into the vector deposited with the ATCC (which is often shown between start and stop codons, inclusive thereof, in the accompanying figures (start and stop codons are bolded and underlined in the figures)).
“Isolated,” when used to describe the various TAHO polypeptides disclosed herein, means polypeptide that has been identified and separated and/or recovered from a component of its natural environment. Contaminant components of its natural environment are materials that would typically interfere with therapeutic uses for the polypeptide, and may include enzymes, hormones, and other proteinaceous or non-proteinaceous solutes. In preferred embodiments, the polypeptide will be purified (1) to a degree sufficient to obtain at least 15 residues of N-terminal or internal amino acid sequence by use of a spinning cup sequenator, or (2) to homogeneity by SDS-PAGE under non-reducing or reducing conditions using Coomassie blue or, preferably, silver stain. Isolated polypeptide includes polypeptide in situ within recombinant cells, since at least one component of the TAHO polypeptide natural environment will not be present. Ordinarily, however, isolated polypeptide will be prepared by at least one purification step.
An “isolated” TAHO polypeptide-encoding nucleic acid or other polypeptide-encoding nucleic acid is a nucleic acid molecule that is identified and separated from at least one contaminant nucleic acid molecule with which it is ordinarily associated in the natural source of the polypeptide-encoding nucleic acid. An isolated polypeptide-encoding nucleic acid molecule is other than in the form or setting in which it is found in nature. Isolated polypeptide-encoding nucleic acid molecules therefore are distinguished from the specific polypeptide-encoding nucleic acid molecule as it exists in natural cells. However, an isolated polypeptide-encoding nucleic acid molecule includes polypeptide-encoding nucleic acid molecules contained in cells that ordinarily express the polypeptide where, for example, the nucleic acid molecule is in a chromosomal location different from that of natural cells.
The term “control sequences” refers to DNA sequences necessary for the expression of an operably linked coding sequence in a particular host organism. The control sequences that are suitable for prokaryotes, for example, include a promoter, optionally an operator sequence, and a ribosome binding site. Eukaryotic cells are known to utilize promoters, polyadenylation signals, and enhancers.
Nucleic acid is “operably linked” when it is placed into a functional relationship with another nucleic acid sequence. For example, DNA for a presequence or secretory leader is operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. Generally, “operably linked” means that the DNA sequences being linked are contiguous, and, in the case of a secretory leader, contiguous and in reading phase. However, enhancers do not have to be contiguous. Linking is accomplished by ligation at convenient restriction sites. If such sites do not exist, the synthetic oligonucleotide adaptors or linkers are used in accordance with conventional practice.
“Stringency” of hybridization reactions is readily determinable by one of ordinary skill in the art, and generally is an empirical calculation dependent upon probe length, washing temperature, and salt concentration. In general, longer probes require higher temperatures for proper annealing, while shorter probes need lower temperatures. Hybridization generally depends on the ability of denatured DNA to reanneal when complementary strands are present in an environment below their melting temperature. The higher the degree of desired homology between the probe and hybridizable sequence, the higher the relative temperature which can be used. As a result, it follows that higher relative temperatures would tend to make the reaction conditions more stringent, while lower temperatures less so. For additional details and explanation of stringency of hybridization reactions, see Ausubel et al., Current Protocols in Molecular Biology, Wiley Interscience Publishers, (1995).
“Stringent conditions” or “high stringency conditions”, as defined herein, may be identified by those that: (1) employ low ionic strength and high temperature for washing, for example 0.015 M sodium chloride/0.0015 M sodium citrate/0.1% sodium dodecyl sulfate at 50° C.; (2) employ during hybridization a denaturing agent, such as formamide, for example, 50% (v/v) formamide with 0.1% bovine serum albumin/0.1% Ficoll/0.1% polyvinylpyrrolidone/50 mM sodium phosphate buffer at pH 6.5 with 750 mM sodium chloride, 75 mM sodium citrate at 42° C.; or (3) overnight hybridization in a solution that employs 50% formamide, 5×SSC (0.75 M NaCl, 0.075 M sodium citrate), 50 mM sodium phosphate (pH 6.8), 0.1% sodium pyrophosphate, 5×Denhardt's solution, sonicated salmon sperm DNA (50 μg/ml), 0.1% SDS, and 10% dextran sulfate at 42° C., with a 10 minute wash at 42° C. in 0.2×SSC (sodium chloride/sodium citrate) followed by a 10 minute high-stringency wash consisting of 0.1×SSC containing EDTA at 55° C.
“Moderately stringent conditions” may be identified as described by Sambrook et al., Molecular Cloning: A Laboratory Manual, New York: Cold Spring Harbor Press, 1989, and include the use of washing solution and hybridization conditions (e.g., temperature, ionic strength and % SDS) less stringent that those described above. An example of moderately stringent conditions is overnight incubation at 37° C. in a solution comprising: 20% formamide, 5×SSC (150 mM NaCl, 15 mM trisodium citrate), 50 mM sodium phosphate (pH 7.6), 5×Denhardt's solution, 10% dextran sulfate, and 20 mg/ml denatured sheared salmon sperm DNA, followed by washing the filters in 1×SSC at about 37-50° C. The skilled artisan will recognize how to adjust the temperature, ionic strength, etc. as necessary to accommodate factors such as probe length and the like.
The term “epitope tagged” when used herein refers to a chimeric polypeptide comprising a TAHO polypeptide or anti-TAHO antibody fused to a “tag polypeptide”. The tag polypeptide has enough residues to provide an epitope against which an antibody can be made, yet is short enough such that it does not interfere with activity of the polypeptide to which it is fused. The tag polypeptide preferably also is fairly unique so that the antibody does not substantially cross-react with other epitopes. Suitable tag polypeptides generally have at least six amino acid residues and usually between about 8 and 50 amino acid residues (preferably, between about 10 and 20 amino acid residues).
“Active” or “activity” for the purposes herein refers to form(s) of a TAHO polypeptide which retain a biological and/or an immunological activity of native or naturally-occurring TAHO, wherein “biological” activity refers to a biological function (either inhibitory or stimulatory) caused by a native or naturally-occurring TAHO other than the ability to induce the production of an antibody against an antigenic epitope possessed by a native or naturally-occurring TAHO and an “immunological” activity refers to the ability to induce the production of an antibody against an antigenic epitope possessed by a native or naturally-occurring TAHO.
The term “antagonist” is used in the broadest sense, and includes any molecule that partially or fully blocks, inhibits, or neutralizes a biological activity of a native TAHO polypeptide disclosed herein. In a similar manner, the term “agonist” is used in the broadest sense and includes any molecule that mimics a biological activity of a native TAHO polypeptide disclosed herein. Suitable agonist or antagonist molecules specifically include agonist or antagonist antibodies or antibody fragments, fragments or amino acid sequence variants of native TAHO polypeptides, peptides, antisense oligonucleotides, small organic molecules, etc. Methods for identifying agonists or antagonists of a TAHO polypeptide may comprise contacting a TAHO polypeptide with a candidate agonist or antagonist molecule and measuring a detectable change in one or more biological activities normally associated with the TAHO polypeptide.
“Purified” means that a molecule is present in a sample at a concentration of at least 95% by weight, or at least 98% by weight of the sample in which it is contained.
An “isolated” nucleic acid molecule is a nucleic acid molecule that is separated from at least one other nucleic acid molecule with which it is ordinarily associated, for example, in its natural environment. An isolated nucleic acid molecule further includes a nucleic acid molecule contained in cells that ordinarily express the nucleic acid molecule, but the nucleic acid molecule is present extrachromasomally or at a chromosomal location that is different from its natural chromosomal location.
The term “vector,” as used herein, is intended to refer to a nucleic acid molecule capable of transporting another nucleic acid to which it has been linked. One type of vector is a “plasmid”, which refers to a circular double stranded DNA loop into which additional DNA segments may be ligated. Another type of vector is a phage vector. Another type of vector is a viral vector, wherein additional DNA segments may be ligated into the viral genome. Certain vectors are capable of autonomous replication in a host cell into which they are introduced (e.g., bacterial vectors having a bacterial origin of replication and episomal mammalian vectors). Other vectors (e.g., non-episomal mammalian vectors) can be integrated into the genome of a host cell upon introduction into the host cell, and thereby are replicated along with the host genome. Moreover, certain vectors are capable of directing the expression of genes to which they are operatively linked. Such vectors are referred to herein as “recombinant expression vectors” (or simply, “recombinant vectors”). In general, expression vectors of utility in recombinant DNA techniques are often in the form of plasmids. In the present specification, “plasmid” and “vector” may be used interchangeably as the plasmid is the most commonly used form of vector.
“Treating” or “treatment” or “alleviation” refers to both therapeutic treatment and prophylactic or preventative measures, wherein the object is to prevent or slow down (lessen) the targeted pathologic condition or disorder. Those in need of treatment include those already with the disorder as well as those prone to have the disorder or those in whom the disorder is to be prevented. A subject or mammal is successfully “treated” for a TAHO polypeptide-expressing cancer if, after receiving a therapeutic amount of an anti-TAHO antibody, TAHO binding oligopeptide or TAHO binding organic molecule according to the methods of the present invention, the patient shows observable and/or measurable reduction in or absence of one or more of the following: reduction in the number of cancer cells or absence of the cancer cells; reduction in the tumor size; inhibition (i.e., slow to some extent and preferably stop) of cancer cell infiltration into peripheral organs including the spread of cancer into soft tissue and bone; inhibition (i.e., slow to some extent and preferably stop) of tumor metastasis; inhibition, to some extent, of tumor growth; and/or relief to some extent, one or more of the symptoms associated with the specific cancer; reduced morbidity and mortality, and improvement in quality of life issues. To the extent the anti-TAHO antibody or TAHO binding oligopeptide may prevent growth and/or kill existing cancer cells, it may be cytostatic and/or cytotoxic. Reduction of these signs or symptoms may also be felt by the patient.
The above parameters for assessing successful treatment and improvement in the disease are readily measurable by routine procedures familiar to a physician. For cancer therapy, efficacy can be measured, for example, by assessing the time to disease progression (TTP) and/or determining the response rate (RR). Metastasis can be determined by staging tests and by bone scan and tests for calcium level and other enzymes to determine spread to the bone. CT scans can also be done to look for spread to the pelvis and lymph nodes in the area. Chest X-rays and measurement of liver enzyme levels by known methods are used to look for metastasis to the lungs and liver, respectively. Other routine methods for monitoring the disease include transrectal ultrasonography (TRUS) and transrectal needle biopsy (TRNB).
For bladder cancer, which is a more localized cancer, methods to determine progress of disease include urinary cytologic evaluation by cystoscopy, monitoring for presence of blood in the urine, visualization of the urothelial tract by sonography or an intravenous pyelogram, computed tomography (CT) and magnetic resonance imaging (MRI). The presence of distant metastases can be assessed by CT of the abdomen, chest x-rays, or radionuclide imaging of the skeleton.
“Chronic” administration refers to administration of the agent(s) in a continuous mode as opposed to an acute mode, so as to maintain the initial therapeutic effect (activity) for an extended period of time. “Intermittenf” administration is treatment that is not consecutively done without interruption, but rather is cyclic in nature.
An “individual” is a vertebrate. In certain embodiments, the vertebrate is a mammal. Mammals include, but are not limited to, farm animals (such as cows), sport animals, pets (such as cats, dogs, and horses), primates, mice and rats. In certain embodiments, a mammal is a human.
“Mammal” for purposes of the treatment of, alleviating the symptoms of a cancer refers to any animal classified as a mammal, including humans, domestic and farm animals, and zoo, sports, or pet animals, such as dogs, cats, cattle, horses, sheep, pigs, goats, rabbits, etc. Preferably, the mammal is human.
Administration “in combination with” one or more further therapeutic agents includes simultaneous (concurrent) and consecutive administration in any order.
“Carriers” as used herein include pharmaceutically acceptable carriers, excipients, or stabilizers which are nontoxic to the cell or mammal being exposed thereto at the dosages and concentrations employed. Often the physiologically acceptable carrier is an aqueous pH buffered solution. Examples of physiologically acceptable carriers include buffers such as phosphate, citrate, and other organic acids; antioxidants including ascorbic acid; low molecular weight (less than about 10 residues) polypeptide; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, arginine or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; sugar alcohols such as mannitol or sorbitol; salt-forming counterions such as sodium; and/or nonionic surfactants such as TWEEN®, polyethylene glycol (PEG), and PLURONICS®.
By “solid phase” or “solid support” is meant a non-aqueous matrix to which an antibody, TAHO binding oligopeptide or TAHO binding organic molecule of the present invention can adhere or attach. Examples of solid phases encompassed herein include those formed partially or entirely of glass (e.g., controlled pore glass), polysaccharides (e.g., agarose), polyacrylamides, polystyrene, polyvinyl alcohol and silicones. In certain embodiments, depending on the context, the solid phase can comprise the well of an assay plate; in others it is a purification column (e.g., an affinity chromatography column). This term also includes a discontinuous solid phase of discrete particles, such as those described in U.S. Pat. No. 4,275,149.
A “liposome” is a small vesicle composed of various types of lipids, phospholipids and/or surfactant which is useful for delivery of a drug (such as a TAHO polypeptide, an antibody thereto or a TAHO binding oligopeptide) to a mammal. The components of the liposome are commonly arranged in a bilayer formation, similar to the lipid arrangement of biological membranes.
A “small” molecule or “small” organic molecule is defined herein to have a molecular weight below about 500 Daltons.
The term “pharmaceutical formulation” refers to a preparation which is in such form as to permit the biological activity of the active ingredient to be effective, and which contains no additional components which are unacceptably toxic to a subject to which the formulation would be administered. Such formulation may be sterile.
A “sterile” formulation is aseptic of free from all living microorganisms and their spores.
An “effective amount” of a polypeptide, antibody, TAHO binding oligopeptide, TAHO binding organic molecule or an agonist or antagonist thereof as disclosed herein is an amount sufficient to carry out a specifically stated purpose. An “effective amount” may be determined empirically and in a routine manner, in relation to the stated purpose.
The term “therapeutically effective amount” refers to an amount of an antibody, polypeptide, TAHO binding oligopeptide, TAHO binding organic molecule or other drug effective to “treat” a disease or disorder in a subject or mammal. In the case of cancer, the therapeutically effective amount of the drug may reduce the number of cancer cells; reduce the tumor size; inhibit (i.e., slow to some extent and preferably stop) cancer cell infiltration into peripheral organs; inhibit (i.e., slow to some extent and preferably stop) tumor metastasis; inhibit, to some extent, tumor growth; and/or relieve to some extent one or more of the symptoms associated with the cancer. See the definition herein of “treating”. To the extent the drug may prevent growth and/or kill existing cancer cells, it may be cytostatic and/or cytotoxic. A “prophylactically effective amount” refers to an amount effective, at dosages and for periods of time necessary, to achieve the desired prophylactic result. Typically but not necessarily, since a prophylactic dose is used in subjects prior to or at an earlier stage of disease, the prophylactically effective amount will be less than the therapeutically effective amount.
A “growth inhibitory amount” of an anti-TAHO antibody, TAHO polypeptide, TAHO binding oligopeptide or TAHO binding organic molecule is an amount capable of inhibiting the growth of a cell, especially tumor, e.g., cancer cell, either in vitro or in vivo. A “growth inhibitory amount” of an anti-TAHO antibody, TAHO polypeptide, TAHO binding oligopeptide or TAHO binding organic molecule for purposes of inhibiting neoplastic cell growth may be determined empirically and in a routine manner.
A “cytotoxic amount” of an anti-TAHO antibody, TAHO polypeptide, TAHO binding oligopeptide or TAHO binding organic molecule is an amount capable of causing the destruction of a cell, especially tumor, e.g., cancer cell, either in vitro or in vivo. A “cytotoxic amount” of an anti-TAHO antibody, TAHO polypeptide, TAHO binding oligopeptide or TAHO binding organic molecule for purposes of inhibiting neoplastic cell growth may be determined empirically and in a routine manner.
The term “antibody” is used in the broadest sense and specifically covers, for example, single anti-TAHO monoclonal antibodies (including agonist, antagonist, and neutralizing antibodies), anti-TAHO antibody compositions with polyepitopic specificity, polyclonal antibodies, single chain anti-TAHO antibodies, and fragments of anti-TAHO antibodies (see below) as long as they exhibit the desired biological or immunological activity. The term “immunoglobulin” (Ig) is used interchangeable with antibody herein.
The term “SN8” is used herein to refer to anti-human CD79b (TAHO5) monoclonal antibody purchased from commercial sources such as Biomeda (Foster City, Calif.), BDbioscience (San Diego, Calif.) or Ancell (Bayport, Minn.), monoclonal antibody generated from hybridomas obtained from Roswell Park Cancer Institute (Okazaki et al., Blood, 81(1): 84-95 (1993)) or chimeric antibody (also referred to herein as “chSN8”) generated using antibody generated from hybridomas obtained from Roswell Park Cancer Institute (Okazaki et al., Blood, 81(1): 84-95 (1993)).
The term “10D10” is used herein to refer to anti-cyno CD79b (TAHO40) monoclonal antibody generated from hybridomas deposited with the ATCC on Jul. 11, 2006 as anti-cyno CD79b (TAHO40) 10D10 (10D10.3) as PTA-7715 or chimeric antibody (also referred to herein as “ch10D10”) generated using antibody generated from hybridomas deposited with the ATCC on Jul. 11, 2006 as anti-cyno CD79b (TAHO40) 10D10 (10D10.3) as PTA-7715.
“ch” when used in reference to an antibody is used herein to specifically refer to chimeric antibody.
“anti-cynoCD79b” or “anti-cyno CD79b” is used herein to refer to antibodies that binds to cyno CD79b (SEQ ID NO: 8 of
An “isolated antibody” is one which has been identified and separated and/or recovered from a component of its natural environment. Contaminant components of its natural environment are materials which would interfere with therapeutic uses for the antibody, and may include enzymes, hormones, and other proteinaceous or nonproteinaceous solutes. In preferred embodiments, the antibody will be purified (1) to greater than 95% by weight of antibody as determined by the Lowry method, and most preferably more than 99% by weight, (2) to a degree sufficient to obtain at least 15 residues of N-terminal or internal amino acid sequence by use of a spinning cup sequenator, or (3) to homogeneity by SDS-PAGE under reducing or nonreducing conditions using Coomassie blue or, preferably, silver stain. Isolated antibody includes the antibody in situ within recombinant cells since at least one component of the antibody's natural environment will not be present. Ordinarily, however, isolated antibody will be prepared by at least one purification step.
The basic 4-chain antibody unit is a heterotetrameric glycoprotein composed of two identical light (L) chains and two identical heavy (H) chains (an IgM antibody consists of 5 of the basic heterotetramer unit along with an additional polypeptide called J chain, and therefore contain 10 antigen binding sites, while secreted IgA antibodies can polymerize to form polyvalent assemblages comprising 2-5 of the basic 4-chain units along with J chain). In the case of IgGs, the 4-chain unit is generally about 150,000 daltons. Each L chain is linked to a H chain by one covalent disulfide bond, while the two H chains are linked to each other by one or more disulfide bonds depending on the H chain isotype. Each H and L chain also has regularly spaced intrachain disulfide bridges. Each H chain has at the N-terminus, a variable domain (VH) followed by three constant domains (CH) for each of the α and γ chains and four CH domains for μ and ε isotypes. Each L chain has at the N-terminus, a variable domain (VL) followed by a constant domain (CL) at its other end. The VL is aligned with the VH and the CL is aligned with the first constant domain of the heavy chain (CH1). Particular amino acid residues are believed to form an interface between the light chain and heavy chain variable domains. The pairing of a VH and VL together forms a single antigen-binding site. For the structure and properties of the different classes of antibodies, see, e.g., Basic and Clinical Immunology, 8th edition, Daniel P. Stites, Abba I. Terr and Tristram G. Parslow (eds.), Appleton & Lange, Norwalk, Conn., 1994, page 71 and Chapter 6.
The L chain from any vertebrate species can be assigned to one of two clearly distinct types, called kappa and lambda, based on the amino acid sequences of their constant domains. Depending on the amino acid sequence of the constant domain of their heavy chains (CH), immunoglobulins can be assigned to different classes or isotypes. There are five classes of immunoglobulins: IgA, IgD, IgE, IgG, and IgM, having heavy chains designated α, δ, ε, γ, and μ, respectively. The γ and α classes are further divided into subclasses on the basis of relatively minor differences in CH sequence and function, e.g., humans express the following subclasses: IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2.
The term “variable” refers to the fact that certain segments of the variable domains differ extensively in sequence among antibodies. The V domain mediates antigen binding and define specificity of a particular antibody for its particular antigen. However, the variability is not evenly distributed across the 110-amino acid span of the variable domains. Instead, the V regions consist of relatively invariant stretches called framework regions (FRs) of 15-30 amino acids separated by shorter regions of extreme variability called “hypervariable regions” that are each 9-12 amino acids long. The variable domains of native heavy and light chains each comprise four FRs, largely adopting a β-sheet configuration, connected by three hypervariable regions, which form loops connecting, and in some cases forming part of, the β-sheet structure. The hypervariable regions in each chain are held together in close proximity by the FRs and, with the hypervariable regions from the other chain, contribute to the formation of the antigen-binding site of antibodies (see Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md. (1991)). The constant domains are not involved directly in binding an antibody to an antigen, but exhibit various effector functions, such as participation of the antibody in antibody dependent cellular cytotoxicity (ADCC).
The term “hypervariable region” when used herein refers to the amino acid residues of an antibody which are responsible for antigen-binding. The hypervariable region generally comprises amino acid residues from a “complementarity determining region” or “CDR” (e.g. around about residues 24-34 (L1), 50-56 (L2) and 89-97 (L3) in the VL, and around about 1-35 (H1), 50-65 (H2) and 95-102 (H3) in the VH; Kabat et al., Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md. (1991)) and/or those residues from a “hypervariable loop” (e.g. residues 26-32 (L1), 50-52 (L2) and 91-96 (L3) in the VL, and 26-32 (H1), 53-55 (H2) and 96-101 (H3) in the VH; Chothia and Lesk J. Mol. Biol. 196:901-917 (1987)).
The term “monoclonal antibody” as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e., the individual antibodies comprising the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single antigenic site. Furthermore, in contrast to polyclonal antibody preparations which include different antibodies directed against different determinants (epitopes), each monoclonal antibody is directed against a single determinant on the antigen. In addition to their specificity, the monoclonal antibodies are advantageous in that they may be synthesized uncontaminated by other antibodies. The modifier “monoclonal” is not to be construed as requiring production of the antibody by any particular method. For example, the monoclonal antibodies useful in the present invention may be prepared by the hybridoma methodology first described by Kohler et al., Nature, 256:495 (1975), or may be made using recombinant DNA methods in bacterial, eukaryotic animal or plant cells (see, e.g., U.S. Pat. No. 4,816,567). The “monoclonal antibodies” may also be isolated from phage antibody libraries using the techniques described in Clackson et al., Nature, 352:624-628 (1991) and Marks et al., J. Mol. Biol., 222:581-597 (1991), for example.
The monoclonal antibodies herein include “chimeric” antibodies in which a portion of the heavy and/or light chain is identical with or homologous to corresponding sequences in antibodies derived from a particular species or belonging to a particular antibody class or subclass, while the remainder of the chain(s) is identical with or homologous to corresponding sequences in antibodies derived from another species or belonging to another antibody class or subclass, as well as fragments of such antibodies, so long as they exhibit the desired biological activity (see U.S. Pat. No. 4,816,567; and Morrison et al., Proc. Natl. Acad. Sci. USA, 81:6851-6855 (1984)). Chimeric antibodies of interest herein include “primatized” antibodies comprising variable domain antigen-binding sequences derived from a non-human primate (e.g. Old World Monkey, Ape etc), and human constant region sequences.
An “intact” antibody is one which comprises an antigen-binding site as well as a CL and at least heavy chain constant domains, CH1, CH2 and CH3. The constant domains may be native sequence constant domains (e.g. human native sequence constant domains) or amino acid sequence variant thereof. Preferably, the intact antibody has one or more effector functions.
“Antibody fragments” comprise a portion of an intact antibody, preferably the antigen binding or variable region of the intact antibody. Examples of antibody fragments include Fab, Fab′, F(ab′)2, and Fv fragments; diabodies; linear antibodies (see U.S. Pat. No. 5,641,870, Example 2; Zapata et al., Protein Eng. 8(10): 1057-1062 [1995]); single-chain antibody molecules; and multispecific antibodies formed from antibody fragments.
Papain digestion of antibodies produces two identical antigen-binding fragments, called “Fab” fragments, and a residual “Fc” fragment, a designation reflecting the ability to crystallize readily. The Fab fragment consists of an entire L chain along with the variable region domain of the H chain (VH), and the first constant domain of one heavy chain (CH1). Each Fab fragment is monovalent with respect to antigen binding, i.e., it has a single antigen-binding site. Pepsin treatment of an antibody yields a single large F(ab′)2 fragment which roughly corresponds to two disulfide linked Fab fragments having divalent antigen-binding activity and is still capable of cross-linking antigen. Fab′ fragments differ from Fab fragments by having additional few residues at the carboxy terminus of the CH1 domain including one or more cysteines from the antibody hinge region. Fab′-SH is the designation herein for Fab′ in which the cysteine residue(s) of the constant domains bear a free thiol group. F(ab′)2 antibody fragments originally were produced as pairs of Fab′ fragments which have hinge cysteines between them. Other chemical couplings of antibody fragments are also known.
The Fc fragment comprises the carboxy-terminal portions of both H chains held together by disulfides. The effector functions of antibodies are determined by sequences in the Fc region, which region is also the part recognized by Fc receptors (FcR) found on certain types of cells.
“Fv” is the minimum antibody fragment which contains a complete antigen-recognition and -binding site. This fragment consists of a dimer of one heavy- and one light-chain variable region domain in tight, non-covalent association. From the folding of these two domains emanate six hypervariable loops (3 loops each from the H and L chain) that contribute the amino acid residues for antigen binding and confer antigen binding specificity to the antibody. However, even a single variable domain (or half of an Fv comprising only three CDRs specific for an antigen) has the ability to recognize and bind antigen, although at a lower affinity than the entire binding site.
“Single-chain Fv” also abbreviated as “sFv” or “scFv” are antibody fragments that comprise the VH and VL antibody domains connected into a single polypeptide chain. Preferably, the sFv polypeptide further comprises a polypeptide linker between the VH and VL domains which enables the sFv to form the desired structure for antigen binding. For a review of sFv, see Pluckthun in The Pharmacology of Monoclonal Antibodies, vol. 113, Rosenburg and Moore eds., Springer-Verlag, New York, pp. 269-315 (1994); Borrebaeck 1995, infra.
The term “diabodies” refers to small antibody fragments prepared by constructing sFv fragments (see preceding paragraph) with short linkers (about 5-10 residues) between the VH and VL domains such that inter-chain but not intra-chain pairing of the V domains is achieved, resulting in a bivalent fragment, i.e., fragment having two antigen-binding sites. Bispecific diabodies are heterodimers of two “crossover” sFv fragments in which the VH and VL domains of the two antibodies are present on different polypeptide chains. Diabodies are described more fully in, for example, EP 404,097; WO 93/11161; and Hollinger et al., Proc. Natl. Acad. Sci. USA, 90:6444-6448 (1993).
“Humanized” forms of non-human (e.g., rodent) antibodies are chimeric antibodies that contain minimal sequence derived from the non-human antibody. For the most part, humanized antibodies are human immunoglobulins (recipient antibody) in which residues from a hypervariable region of the recipient are replaced by residues from a hypervariable region of a non-human species (donor antibody) such as mouse, rat, rabbit or non-human primate having the desired antibody specificity, affinity, and capability. In some instances, framework region (FR) residues of the human immunoglobulin are replaced by corresponding non-human residues. Furthermore, humanized antibodies may comprise residues that are not found in the recipient antibody or in the donor antibody. These modifications are made to further refine antibody performance. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the hypervariable loops correspond to those of a non-human immunoglobulin and all or substantially all of the FRs are those of a human immunoglobulin sequence. The humanized antibody optionally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin. For further details, see Jones et al., Nature 321:522-525 (1986); Riechmann et al., Nature 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol. 2:593-596 (1992).
A “species-dependent antibody,” e.g., a mammalian anti-human IgE antibody, is an antibody which has a stronger binding affinity for an antigen from a first mammalian species than it has for a homologue of that antigen from a second mammalian species. Normally, the species-dependent antibody “bind specifically” to a human antigen (i.e., has a binding affinity (Kd) value of no more than about 1×10−7 M, preferably no more than about 1×10−8 and most preferably no more than about 1×10−9 M) but has a binding affinity for a homologue of the antigen from a second non-human mammalian species which is at least about 50 fold, or at least about 500 fold, or at least about 1000 fold, weaker than its binding affinity for the human antigen. The species-dependent antibody can be of any of the various types of antibodies as defined above, but preferably is a humanized or human antibody.
A “TAHO binding oligopeptide” is an oligopeptide that binds, preferably specifically, to a TAHO polypeptide as described herein. TAHO binding oligopeptides may be chemically synthesized using known oligopeptide synthesis methodology or may be prepared and purified using recombinant technology. TAHO binding oligopeptides are usually at least about 5 amino acids in length, alternatively at least about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 amino acids in length or more, wherein such oligopeptides that are capable of binding, preferably specifically, to a TAHO polypeptide as described herein. TAHO binding oligopeptides may be identified without undue experimentation using well known techniques. In this regard, it is noted that techniques for screening oligopeptide libraries for oligopeptides that are capable of specifically binding to a polypeptide target are well known in the art (see, e.g., U.S. Pat. Nos. 5,556,762, 5,750,373, 4,708,871, 4,833,092, 5,223,409, 5,403,484, 5,571,689, 5,663,143; PCT Publication Nos. WO 84/03506 and WO84/03564; Geysen et al., Proc. Natl. Acad. Sci. U.S.A., 81:3998-4002 (1984); Geysen et al., Proc. Natl. Acad. Sci. U.S.A., 82:178-182 (1985); Geysen et al., in Synthetic Peptides as Antigens, 130-149 (1986); Geysen et al., J. Immunol. Meth., 102:259-274 (1987); Schoofs et al., J. Immunol., 140:611-616 (1988), Cwirla, S. E. et al. (1990) Proc. Natl. Acad. Sci. USA, 87:6378; Lowman, H. B. et al. (1991) Biochemistry, 30:10832; Clackson, T. et al. (1991) Nature, 352: 624; Marks, J. D. et al. (1991), J. Mol. Biol., 222:581; Kang, A. S. et al. (1991) Proc. Natl. Acad. Sci. USA, 88:8363, and Smith, G. P. (1991) Current Opin. Biotechnol., 2:668).
A “TAHO binding organic molecule” is an organic molecule other than an oligopeptide or antibody as defined herein that binds, preferably specifically, to a TAHO polypeptide as described herein. TAHO binding organic molecules may be identified and chemically synthesized using known methodology (see, e.g., PCT Publication Nos. WO00/00823 and WO00/39585). TAHO binding organic molecules are usually less than about 2000 daltons in size, alternatively less than about 1500, 750, 500, 250 or 200 daltons in size, wherein such organic molecules that are capable of binding, preferably specifically, to a TAHO polypeptide as described herein may be identified without undue experimentation using well known techniques. In this regard, it is noted that techniques for screening organic molecule libraries for molecules that are capable of binding to a polypeptide target are well known in the art (see, e.g., PCT Publication Nos. WO00/00823 and WO00/39585).
An antibody, oligopeptide or other organic molecule “which binds” an antigen of interest, e.g. a tumor-associated polypeptide antigen target, is one that binds the antigen with sufficient affinity such that the antibody, oligopeptide or other organic molecule is useful as a therapeutic agent in targeting a cell or tissue expressing the antigen, and does not significantly cross-react with other proteins. In such embodiments, the extent of binding of the antibody, oligopeptide or other organic molecule to a “non-target” protein will be less than about 10% of the binding of the antibody, oligopeptide or other organic molecule to its particular target protein as determined by fluorescence activated cell sorting (FACS) analysis or radioimmunoprecipitation (RIA). With regard to the binding of an antibody, oligopeptide or other organic molecule to a target molecule, the term “specific binding” or “specifically binds to” or is “specific for” a particular polypeptide or an epitope on a particular polypeptide target means binding that is measurably different from a non-specific interaction. Specific binding can be measured, for example, by determining binding of a molecule compared to binding of a control molecule, which generally is a molecule of similar structure that does not have binding activity. For example, specific binding can be determined by competition with a control molecule that is similar to the target, for example, an excess of non-labeled target. In this case, specific binding is indicated if the binding of the labeled target to a probe is competitively inhibited by excess unlabeled target. The term “specific binding” or “specifically binds to” or is “specific for” a particular polypeptide or an epitope on a particular polypeptide target as used herein can be exhibited, for example, by a molecule having a Kd for the target of at least about 10−4 M, alternatively at least about 10−5 M, alternatively at least about 10−6 M, alternatively at least about 10−7 M, alternatively at least about 10−8 M, alternatively at least about 10−9 M, alternatively at least about 10−10 M, alternatively at least about 10−11 M, alternatively at least about 10−12 M, or greater. In one embodiment, the term “specific binding” refers to binding where a molecule binds to a particular polypeptide or epitope on a particular polypeptide without substantially binding to any other polypeptide or polypeptide epitope.
An antibody, oligopeptide or other organic molecule that “inhibits the growth of tumor cells expressing a TAHO polypeptide” or a “growth inhibitory” antibody, oligopeptide or other organic molecule is one which results in measurable growth inhibition of cancer cells expressing or overexpressing the appropriate TAHO polypeptide. The TAHO polypeptide may be a transmembrane polypeptide expressed on the surface of a cancer cell or may be a polypeptide that is produced and secreted by a cancer cell. Preferred growth inhibitory anti-TAHO antibodies, oligopeptides or organic molecules inhibit growth of TAHO-expressing tumor cells by greater than 20%, preferably from about 20% to about 50%, and even more preferably, by greater than 50% (e.g., from about 50% to about 100%) as compared to the appropriate control, the control typically being tumor cells not treated with the antibody, oligopeptide or other organic molecule being tested. In one embodiment, growth inhibition can be measured at an antibody concentration of about 0.1 to 30 μg/ml or about 0.5 nM to 200 nM in cell culture, where the growth inhibition is determined 1-10 days after exposure of the tumor cells to the antibody. Growth inhibition of tumor cells in vivo can be determined in various ways such as is described in the Experimental Examples section below. The antibody is growth inhibitory in vivo if administration of the anti-TAHO antibody at about 1 μg/kg to about 100 mg/kg body weight results in reduction in tumor size or tumor cell proliferation within about 5 days to 3 months from the first administration of the antibody, preferably within about 5 to 30 days.
An antibody, oligopeptide or other organic molecule which “induces apoptosis” is one which induces programmed cell death as determined by binding of annexin V, fragmentation of DNA, cell shrinkage, dilation of endoplasmic reticulum, cell fragmentation, and/or formation of membrane vesicles (called apoptotic bodies). The cell is usually one which overexpresses a TAHO polypeptide. Preferably the cell is a tumor cell, e.g., a hematopoietic cell, such as a B cell, T cell, basophil, eosinophil, neutrophil, monocyte, platelet or erythrocyte. Various methods are available for evaluating the cellular events associated with apoptosis. For example, phosphatidyl serine (PS) translocation can be measured by annexin binding; DNA fragmentation can be evaluated through DNA laddering; and nuclear/chromatin condensation along with DNA fragmentation can be evaluated by any increase in hypodiploid cells. Preferably, the antibody, oligopeptide or other organic molecule which induces apoptosis is one which results in about 2 to 50 fold, preferably about 5 to 50 fold, and most preferably about 10 to 50 fold, induction of annexin binding relative to untreated cell in an annexin binding assay.
Antibody “effector functions” refer to those biological activities attributable to the Fc region (a native sequence Fc region or amino acid sequence variant Fc region) of an antibody, and vary with the antibody isotype. Examples of antibody effector functions include: C1q binding and complement dependent cytotoxicity; Fc receptor binding; antibody-dependent cell-mediated cytotoxicity (ADCC); phagocytosis; down regulation of cell surface receptors (e.g., B cell receptor); and B cell activation.
“Antibody-dependent cell-mediated cytotoxicity” or “ADCC” refers to a form of cytotoxicity in which secreted Ig bound onto Fc receptors (FcRs) present on certain cytotoxic cells (e.g., Natural Killer (NK) cells, neutrophils, and macrophages) enable these cytotoxic effector cells to bind specifically to an antigen-bearing target cell and subsequently kill the target cell with cytotoxins. The antibodies “arm” the cytotoxic cells and are absolutely required for such killing. The primary cells for mediating ADCC, NK cells, express FcγRIII only, whereas monocytes express FcγRI, FcγRII and FcγRIII. FcR expression on hematopoietic cells is summarized in Table 3 on page 464 of Ravetch and Kinet, Annu. Rev. Immunol. 9:457-92 (1991). To assess ADCC activity of a molecule of interest, an in vitro ADCC assay, such as that described in U.S. Pat. No. 5,500,362 or 5,821,337 may be performed. Useful effector cells for such assays include peripheral blood mononuclear cells (PBMC) and Natural Killer (NK) cells. Alternatively, or additionally, ADCC activity of the molecule of interest may be assessed in vivo, e.g., in a animal model such as that disclosed in Clynes et al. (USA) 95:652-656 (1998).
“Fc receptor” or “FcR” describes a receptor that binds to the Fc region of an antibody. The preferred FcR is a native sequence human FcR. Moreover, a preferred FcR is one which binds an IgG antibody (a gamma receptor) and includes receptors of the FcγRI, FcγRII and FcγRIII subclasses, including allelic variants and alternatively spliced forms of these receptors. FcγRII receptors include FcγRIIA (an “activating receptor”) and FcγRIIB (an “inhibiting receptor”), which have similar amino acid sequences that differ primarily in the cytoplasmic domains thereof. Activating receptor FcγRIIA contains an immunoreceptor tyrosine-based activation motif (ITAM) in its cytoplasmic domain. Inhibiting receptor FcγRIIB contains an immunoreceptor tyrosine-based inhibition motif (ITIM) in its cytoplasmic domain. (see review M. in Daëron, Annu. Rev. Immunol. 15:203-234 (1997)). FcRs are reviewed in Ravetch and Kinet, Annu. Rev. Immunol. 9:457-492 (1991); Capel et al., Immunomethods 4:25-34 (1994); and de Haas et al., J. Lab. Clin. Med. 126:330-41 (1995). Other FcRs, including those to be identified in the future, are encompassed by the term “FcR” herein. The term also includes the neonatal receptor, FcRn, which is responsible for the transfer of maternal IgGs to the fetus (Guyer et al., J. Immunol. 117:587 (1976) and Kim et al., J. Immunol. 24:249 (1994)).
“Human effector cells” are leukocytes which express one or more FcRs and perform effector functions. Preferably, the cells express at least FcγRIII and perform ADCC effector function. Examples of human leukocytes which mediate ADCC include peripheral blood mononuclear cells (PBMC), natural killer (NK) cells, monocytes, cytotoxic T cells and neutrophils; with PBMCs and NK cells being preferred. The effector cells may be isolated from a native source, e.g., from blood.
“Complement dependent cytotoxicity” or “CDC” refers to the lysis of a target cell in the presence of complement. Activation of the classical complement pathway is initiated by the binding of the first component of the complement system (C1q) to antibodies (of the appropriate subclass) which are bound to their cognate antigen. To assess complement activation, a CDC assay, e.g., as described in Gazzano-Santoro et al., J. Immunol. Methods 202:163 (1996), may be performed.
The terms “cancer” and “cancerous” refer to or describe the physiological condition in mammals that is typically characterized by unregulated cell growth. Examples of cancer include, but are not limited to, hematopoietic cancers or blood-related cancers, such as lymphoma, leukemia, myeloma or lymphoid malignancies, but also cancers of the spleen and cancers of the lymph nodes. More particular examples of such B-cell associated cancers, including for example, high, intermediate and low grade lymphomas (including B cell lymphomas such as, for example, mucosa-associated-lymphoid tissue B cell lymphoma and non-Hodgkin's lymphoma, mantle cell lymphoma, Burkitt's lymphoma, small lymphocytic lymphoma, marginal zone lymphoma, diffuse large cell lymphoma, follicular lymphoma, and Hodgkin's lymphoma and T cell lymphomas) and leukemias (including secondary leukemia, chronic lymphocytic leukemia, such as B cell leukemia (CD5+ B lymphocytes), myeloid leukemia, such as acute myeloid leukemia, chronic myeloid leukemia, lymphoid leukemia, such as acute lymphoblastic leukemia and myelodysplasia), multiple myeloma, such as plasma cell malignancy, and other hematological and/or B cell- or T-cell-associated cancers. Also included are cancers of additional hematopoietic cells, including polymorphonuclear leukocytes, such as basophils, eosinophils, neutrophils and monocytes, dendritic cells, platelets, erythrocytes and natural killer cells. The origins of B-cell cancers are as follows: marginal zone B-cell lymphoma origins in memory B-cells in marginal zone, follicular lymphoma and diffuse large B-cell lymphoma originates in centrocytes in the light zone of germinal centers, multiple myeloma originates in plasma cells, chronic lymphocytic leukemia and small lymphocytic leukemia originates in B1 cells (CD5+), mantle cell lymphoma originates in naive B-cells in the mantle zone and Burkitt's lymphoma originates in centroblasts in the dark zone of germinal centers. Tissues which include hematopoietic cells referred herein to as “hematopoietic cell tissues” include thymus and bone marrow and peripheral lymphoid tissues, such as spleen, lymph nodes, lymphoid tissues associated with mucosa, such as the gut-associated lymphoid tissues, tonsils, Peyer's patches and appendix and lymphoid tissues associated with other mucosa, for example, the bronchial linings. Further particular examples of such cancers include squamous cell cancer, small-cell lung cancer, non-small cell lung cancer, adenocarcinoma of the lung, squamous carcinoma of the lung, cancer of the peritoneum, hepatocellular cancer, gastrointestinal cancer, pancreatic cancer, glioma, cervical cancer, ovarian cancer, liver cancer, bladder cancer, hepatoma, breast cancer, colon cancer, colorectal cancer, endometrial or uterine carcinoma, salivary gland carcinoma, kidney cancer, liver cancer, prostate cancer, vulval cancer, thyroid cancer, hepatic carcinoma, leukemia and other lymphoproliferative disorders, and various types of head and neck cancer.
A “B-cell malignancy” herein includes non-Hodgkin's lymphoma (NHL), including low grade/follicular NHL, small lymphocytic (SL) NHL, intermediate grade/follicular NHL, intermediate grade diffuse NHL, high grade immunoblastic NHL, high grade lymphoblastic NHL, high grade small non-cleaved cell NHL, bulky disease NHL, mantle cell lymphoma, AIDS-related lymphoma, and Waldenstrom's Macroglobulinemia, non-Hodgkin's lymphoma (NHL), lymphocyte predominant Hodgkin's disease (LPHD), small lymphocytic lymphoma (SLL), chronic lymphocytic leukemia (CLL), indolent NHL including relapsed indolent NHL and rituximab-refractory indolent NHL; leukemia, including acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), Hairy cell leukemia, chronic myeloblastic leukemia; mantle cell lymphoma; and other hematologic malignancies. Such malignancies may be treated with antibodies directed against B-cell surface markers, such as a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40). Such diseases are contemplated herein to be treated by the administration of an antibody directed against a B cell surface marker, such as a TAHO polypeptide, such as human CD79b (TAHO5) and/or cyno CD79b (TAHO40), and includes the administration of an unconjugated (“naked”) antibody or an antibody conjugated to a cytotoxic agent as disclosed herein. Such diseases are also contemplated herein to be treated by combination therapy including an anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody or anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody drug conjugate of the invention in combination with another antibody or antibody drug conjugate, another cytoxic agent, radiation or other treatment administered simultaneously or in series. In exemplary treatment method of the invention, an anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody of the invention is administered in combination with an anti-CD20 antibody, immunoglobulin, or CD20 binding fragment thereof, either together or sequentially. The anti-CD20 antibody may be a naked antibody or an antibody drug conjugate. In an embodiment of the combination therapy, the anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody is an antibody of the present invention and the anti-CD20 antibody is Rituxan(r) (rituximab).
The term “non-Hodgkin's lymphoma” or “NHL”, as used herein, refers to a cancer of the lymphatic system other than Hodgkin's lymphomas. Hodgkin's lymphomas can generally be distinguished from non-Hodgkin's lymphomas by the presence of Reed-Sternberg cells in Hodgkin's lymphomas and the absence of said cells in non-Hodgkin's lymphomas. Examples of non-Hodgkin's lymphomas encompassed by the term as used herein include any that would be identified as such by one skilled in the art (e.g., an oncologist or pathologist) in accordance with classification schemes known in the art, such as the Revised European-American Lymphoma (REAL) scheme as described in Color Atlas of Clinical Hematology (3rd edition), A. Victor Hoffbrand and John E. Pettit (eds.) (Harcourt Publishers Ltd., 2000). See, in particular, the lists in
A “disorder” is any condition that would benefit from treatment with a substance/molecule or method of the invention. This includes chronic and acute disorders or diseases including those pathological conditions which predispose the mammal to the disorder in question. Non-limiting examples of disorders to be treated herein include cancerous conditions such as malignant and benign tumors; non-leukemias and lymphoid malignancies; neuronal, glial, astrocytal, hypothalamic and other glandular, macrophagal, epithelial, stromal and blastocoelic disorders; and inflammatory, immunologic and other angiogenesis-related disorders. Disorders further include cancerous conditions such as B cell proliferative disorders and/or B cell tumors, e.g., lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
The terms “cell proliferative disorder” and “proliferative disorder” refer to disorders that are associated with some degree of abnormal cell proliferation. In one embodiment, the cell proliferative disorder is cancer.
“Tumor”, as used herein, refers to all neoplastic cell growth and proliferation, whether malignant or benign, and all pre-cancerous and cancerous cells and tissues.
An antibody, oligopeptide or other organic molecule which “induces cell death” is one which causes a viable cell to become nonviable. The cell is one which expresses a TAHO polypeptide and is of a cell type which specifically expresses or overexpresses a TAHO polypeptide. The cell may be cancerous or normal cells of the particular cell type. The TAHO polypeptide may be a transmembrane polypeptide expressed on the surface of a cancer cell or may be a polypeptide that is produced and secreted by a cancer cell. The cell may be a cancer cell, e.g., a B cell or T cell. Cell death in vitro may be determined in the absence of complement and immune effector cells to distinguish cell death induced by antibody-dependent cell-mediated cytotoxicity (ADCC) or complement dependent cytotoxicity (CDC). Thus, the assay for cell death may be performed using heat inactivated serum (i.e., in the absence of complement) and in the absence of immune effector cells. To determine whether the antibody, oligopeptide or other organic molecule is able to induce cell death, loss of membrane integrity as evaluated by uptake of propidium iodide (PI), trypan blue (see Moore et al. Cytotechnology 17:1-11 (1995)) or 7AAD can be assessed relative to untreated cells. Preferred cell death-inducing antibodies, oligopeptides or other organic molecules are those which induce PI uptake in the PI uptake assay in BT474 cells.
A “TAHO-expressing cell” is a cell which expresses an endogenous or transfected TAHO polypeptide either on the cell surface or in a secreted form. A “TAHO-expressing cancer” is a cancer comprising cells that have a TAHO polypeptide present on the cell surface or that produce and secrete a TAHO polypeptide. A “TAHO-expressing cancer” optionally produces sufficient levels of TAHO polypeptide on the surface of cells thereof, such that an anti-TAHO antibody, oligopeptide to other organic molecule can bind thereto and have a therapeutic effect with respect to the cancer. In another embodiment, a “TAHO-expressing cancer” optionally produces and secretes sufficient levels of TAHO polypeptide, such that an anti-TAHO antibody, oligopeptide to other organic molecule antagonist can bind thereto and have a therapeutic effect with respect to the cancer. With regard to the latter, the antagonist may be an antisense oligonucleotide which reduces, inhibits or prevents production and secretion of the secreted TAHO polypeptide by tumor cells. A cancer which “overexpresses” a TAHO polypeptide is one which has significantly higher levels of TAHO polypeptide at the cell surface thereof, or produces and secretes, compared to a noncancerous cell of the same tissue type. Such overexpression may be caused by gene amplification or by increased transcription or translation. TAHO polypeptide overexpression may be determined in a detection or prognostic assay by evaluating increased levels of the TAHO protein present on the surface of a cell, or secreted by the cell (e.g., via an immunohistochemistry assay using anti-TAHO antibodies prepared against an isolated TAHO polypeptide which may be prepared using recombinant DNA technology from an isolated nucleic acid encoding the TAHO polypeptide; FACS analysis, etc.). Alternatively, or additionally, one may measure levels of TAHO polypeptide-encoding nucleic acid or mRNA in the cell, e.g., via fluorescent in situ hybridization using a nucleic acid based probe corresponding to a TAHO-encoding nucleic acid or the complement thereof; (FISH; see WO98/45479 published October, 1998), Southern blotting, Northern blotting, or polymerase chain reaction (PCR) techniques, such as real time quantitative PCR (RT-PCR). One may also study TAHO polypeptide overexpression by measuring shed antigen in a biological fluid such as serum, e.g., using antibody-based assays (see also, e.g., U.S. Pat. No. 4,933,294 issued Jun. 12, 1990; WO91/05264 published Apr. 18, 1991; U.S. Pat. No. 5,401,638 issued Mar. 28, 1995; and Sias et al., J. Immunol. Methods 132:73-80 (1990)). Aside from the above assays, various in vivo assays are available to the skilled practitioner. For example, one may expose cells within the body of the patient to an antibody which is optionally labeled with a detectable label, e.g., a radioactive isotope, and binding of the antibody to cells in the patient can be evaluated, e.g., by external scanning for radioactivity or by analyzing a biopsy taken from a patient previously exposed to the antibody.
As used herein, the term “immunoadhesin” designates antibody-like molecules which combine the binding specificity of a heterologous protein (an “adhesin”) with the effector functions of immunoglobulin constant domains. Structurally, the immunoadhesins comprise a fusion of an amino acid sequence with the desired binding specificity which is other than the antigen recognition and binding site of an antibody (i.e., is “heterologous”), and an immunoglobulin constant domain sequence. The adhesin part of an immunoadhesin molecule typically is a contiguous amino acid sequence comprising at least the binding site of a receptor or a ligand. The immunoglobulin constant domain sequence in the immunoadhesin may be obtained from any immunoglobulin, such as IgG-1, IgG-2, IgG-3, or IgG-4 subtypes, IgA (including IgA-1 and IgA-2), IgE, IgD or IgM.
The word “label” when used herein refers to a detectable compound or composition which is conjugated directly or indirectly to the antibody, oligopeptide or other organic molecule so as to generate a “labeled” antibody, oligopeptide or other organic molecule. The label may be detectable by itself (e.g. radioisotope labels or fluorescent labels) or, in the case of an enzymatic label, may catalyze chemical alteration of a substrate compound or composition which is detectable.
The term “cytotoxic agent” as used herein refers to a substance that inhibits or prevents the function of cells and/or causes destruction of cells. The term is intended to include radioactive isotopes (e.g., At211, I131, I125, Y90, Re186, Re188, Sm153, Bi212, P32 and radioactive isotopes of Lu), chemotherapeutic agents e.g. methotrexate, adriamicin, vinca alkaloids (vincristine, vinblastine, etoposide), doxorubicin, melphalan, mitomycin C, chlorambucil, daunorubicin or other intercalating agents, enzymes and fragments thereof such as nucleolytic enzymes, antibiotics, and toxins such as small molecule toxins or enzymatically active toxins of bacterial, fungal, plant or animal origin, including fragments and/or variants thereof, and the various antitumor or anticancer agents disclosed below. Other cytotoxic agents are described below. A tumoricidal agent causes destruction of tumor cells.
A “toxin” is any substance capable of having a detrimental effect on the growth or proliferation of a cell.
A “chemotherapeutic agent” is a chemical compound useful in the treatment of cancer, regardless of mechanism of action. Classes of chemotherapeutic agents include, but are not limited to: alkyating agents, antimetabolites, spindle poison plant alkaloids, cytoxic/antitumor antibiotics, topoisomerase inhibitors, antibodies, photosensitizers, and kinase inhibitors. Chemotherapeutic agents include compounds used in “targeted therapy” and conventional chemotherapy. Examples of chemotherapeutic agents include: erlotinib (TARCEVA®, Genentech/OSI Pharm.), docetaxel (TAXOTERE®, Sanofi-Aventis), 5-FU (fluorouracil, 5-fluorouracil, CAS No. 51-21-8), gemcitabine (GEMZAR®, Lilly), PD-0325901 (CAS No. 391210-10-9, Pfizer), cisplatin (cis-diamine, dichloroplatinum(II), CAS No. 15663-27-1), carboplatin (CAS No. 41575-94-4), paclitaxel (TAXOL®, Bristol-Myers Squibb Oncology, Princeton, N.J.), trastuzumab (HERCEPTIN®, Genentech), temozolomide (4-methyl-5-oxo-2,3,4,6,8-pentazabicyclo [4.3.0] nona-2,7,9-triene-9-carboxamide, CAS No. 85622-93-1, TEMODAR®, TEMODAL®, Schering Plough), tamoxifen ((Z)-2-[4-(1,2-diphenylbut-1-enyl)phenoxy]-N,N-dimethyl-ethanamine, NOLVADEX®, ISTUBAL®, VALODEX®), and doxorubicin (ADRIAMYCIN®), Akti-1/2, HPPD, and rapamycin.
More examples of chemotherapeutic agents include: oxaliplatin (ELOXATIN®, Sanofi), bortezomib (VELCADE®, Millennium Pharm.), sutent (SUNITINIB®, SUl 1248, Pfizer), letrozole (FEMARA®, Novartis), imatinib mesylate (GLEEVEC®, Novartis), XL-518 (Mek inhibitor, Exelixis, WO 2007/044515), ARRY-886 (Mek inhibitor, AZD6244, Array BioPharma, Astra Zeneca), SF-1126 (PI3K inhibitor, Semafore Pharmaceuticals), BEZ-235 (PI3K inhibitor, Novartis), XL-147 (PI3K inhibitor, Exelixis), PTK787/ZK 222584 (Novartis), fulvestrant (FASLODEX®, AstraZeneca), leucovorin (folinic acid), rapamycin (sirolimus, RAPAMUNE®, Wyeth), lapatinib (TYKERB®, GSK572016, Glaxo Smith Kline), lonafarnib (SARASAR™, SCH 66336, Schering Plough), sorafenib (NEXAVAR®, BAY43-9006, Bayer Labs), gefitinib (IRESSA®, AstraZeneca), irinotecan (CAMPTOSAR®, CPT-11, Pfizer), tipifarnib (ZARNESTRA™, Johnson & Johnson), ABRAXANE™ (Cremophor-free), albumin-engineered nanoparticle formulations of paclitaxel (American Pharmaceutical Partners, Schaumberg, II), vandetanib (rINN, ZD6474, ZACTIMA®, AstraZeneca), chloranmbucil, AG1478, AG1571 (SU 5271; Sugen), temsirolimus (TORISEL®, Wyeth), pazopanib (GlaxoSmithKline), canfosfamide (TELCYTA®, Telik), thiotepa and cyclosphosphamide (CYTOXAN®, NEOSAR®); alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines including altretamine, triethylenemelamine, triethylenephosphoramide, triethylenethiophosphoramide and trimethylomelamine; acetogenins (especially bullatacin and bullatacinone); a camptothecin (including the synthetic analog topotecan); bryostatin; callystatin; CC-1065 (including its adozelesin, carzelesin and bizelesin synthetic analogs); cryptophycins (particularly cryptophycin 1 and cryptophycin 8); dolastatin; duocarmycin (including the synthetic analogs, KW-2189 and CB1-TM1); eleutherobin; pancratistatin; a sarcodictyin; spongistatin; nitrogen mustards such as chlorambucil, chlornaphazine, chlorophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosoureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, and ranimnustine; antibiotics such as the enediyne antibiotics (e.g., calicheamicin, calicheamicin gamma1I, calicheamicin omegaI1 (Angew Chem. Intl. Ed. Engl. (1994) 33:183-186); dynemicin, dynemicin A; bisphosphonates, such as clodronate; an esperamicin; as well as neocarzinostatin chromophore and related chromoprotein enediyne antibiotic chromophores), aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, carabicin, caminomycin, carzinophilin, chromomycinis, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, morpholino-doxorubicin, cyanomorpholino-doxorubicin, 2-pyrrolino-doxorubicin and deoxydoxorubicin), epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins such as mitomycin C, mycophenolic acid, nogalamycin, olivomycins, peplomycin, porfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5-fluorouracil (5-FU); folic acid analogs such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogs such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogs such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; eniluracil; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elformithine; elliptinium acetate; an epothilone; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidainine; maytansinoids such as maytansine and ansamitocins; mitoguazone; mitoxantrone; mopidanmol; nitraerine; pentostatin; phenamet; pirarubicin; losoxantrone; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK® polysaccharide complex (JHS Natural Products, Eugene, Oreg.); razoxane; rhizoxin; sizofuran; spirogermanium; tenuazonic acid; triaziquone; 2,2′,2″-trichlorotriethylamine; trichothecenes (especially T-2 toxin, verracurin A, roridin A and anguidine); urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside (“Ara-C”); cyclophosphamide; thiotepa; 6-thioguanine; mercaptopurine; methotrexate; platinum analogs such as cisplatin and carboplatin; vinblastine; etoposide (VP-16); ifosfamide; mitoxantrone; vincristine; vinorelbine (NAVELBINE®); novantrone; teniposide; edatrexate; daunomycin; aminopterin; capecitabine (XELODA®, Roche); ibandronate; CPT-11; topoisomerase inhibitor RFS 2000; difluoromethylornithine (DMFO); retinoids such as retinoic acid; and pharmaceutically acceptable salts, acids and derivatives of any of the above.
Also included in the definition of “chemotherapeutic agent” are: (i) anti-hormonal agents that act to regulate or inhibit hormone action on tumors such as anti-estrogens and selective estrogen receptor modulators (SERMs), including, for example, tamoxifen (including NOLVADEX®; tamoxifen citrate), raloxifene, droloxifene, 4-hydroxytamoxifen, trioxifene, keoxifene, LY117018, onapristone, and FARESTON® (toremifine citrate); (ii) aromatase inhibitors that inhibit the enzyme aromatase, which regulates estrogen production in the adrenal glands, such as, for example, 4(5)-imidazoles, aminoglutethimide, MEGASE® (megestrol acetate), AROMASIN® (exemestane; Pfizer), formestanie, fadrozole, RIVISOR® (vorozole), FEMARA® (letrozole; Novartis), and ARIMIDEX® (anastrozole; AstraZeneca); (iii) anti-androgens such as flutamide, nilutamide, bicalutamide, leuprolide, and goserelin; as well as troxacitabine (a 1,3-dioxolane nucleoside cytosine analog); (iv) protein kinase inhibitors such as MEK inhibitors (WO 2007/044515); (v) lipid kinase inhibitors; (vi) antisense oligonucleotides, particularly those which inhibit expression of genes in signaling pathways implicated in aberrant cell proliferation, for example, PKC-alpha, Raf and H-Ras, such as oblimersen (GENASENSE®, Genta Inc.); (vii) ribozymes such as VEGF expression inhibitors (e.g., ANGIOZYME®) and HER2 expression inhibitors; (viii) vaccines such as gene therapy vaccines, for example, ALLOVECTIN®, LEUVECTIN®, and VAXID®; PROLEUKIN® rIL-2; topoisomerase 1 inhibitors such as LURTOTECAN®; ABARELIX® rmRH; (ix) anti-angiogenic agents such as bevacizumab (AVASTIN®, Genentech); and pharmaceutically acceptable salts, acids and derivatives of any of the above.
Also included in the definition of “chemotherapeutic agent” are therapeutic antibodies such as alemtuzumab (Campath), bevacizumab (AVASTIN®, Genentech); cetuximab (ERBITUX®, Imclone); panitumumab (VECTIBIX®, Amgen), rituximab (RITUXAN®, Genentech/Biogen Idec), pertuzumab (OMNITARG™, 2C4, Genentech), trastuzumab (HERCEPTIN®, Genentech), tositumomab (Bexxar, Corixia), and the antibody drug conjugate, gemtuzumab ozogamicin (MYLOTARG®, Wyeth).
A “growth inhibitory agent” when used herein refers to a compound or composition which inhibits growth of a cell, especially a TAHO-expressing cancer cell, either in vitro or in vivo. Thus, the growth inhibitory agent may be one which significantly reduces the percentage of TAHO-expressing cells in S phase. Examples of growth inhibitory agents include agents that block cell cycle progression (at a place other than S phase), such as agents that induce G1 arrest and M-phase arrest. Classical M-phase blockers include the vincas (vincristine and vinblastine), taxanes, and topoisomerase II inhibitors such as doxorubicin, epirubicin, daunorubicin, etoposide, and bleomycin. Those agents that arrest G1 also spill over into S-phase arrest, for example, DNA alkylating agents such as tamoxifen, prednisone, dacarbazine, mechlorethamine, cisplatin, methotrexate, 5-fluorouracil, and ara-C. Further information can be found in The Molecular Basis of Cancer, Mendelsohn and Israel, eds., Chapter 1, entitled “Cell cycle regulation, oncogenes, and antineoplastic drugs” by Murakami et al. (WB Saunders: Philadelphia, 1995), especially p. 13. The taxanes (paclitaxel and docetaxel) are anticancer drugs both derived from the yew tree. Docetaxel (TAXOTERE®, Rhone-Poulenc Rorer), derived from the European yew, is a semisynthetic analogue of paclitaxel (TAXOL®, Bristol-Myers Squibb). Paclitaxel and docetaxel promote the assembly of microtubules from tubulin dimers and stabilize microtubules by preventing depolymerization, which results in the inhibition of mitosis in cells.
“Doxorubicin” is an anthracycline antibiotic. The full chemical name of doxorubicin is (8S-cis)-10-[(3-amino-2,3,6-trideoxy-α-L-lyxo-hexapyranosyl)oxy]-7,8,9,10-tetrahydro-6,8,11-trihydroxy-8-(hydroxyacetyl)-1-methoxy-5,12-naphthacenedione.
The term “cytokine” is a generic term for proteins released by one cell population which act on another cell as intercellular mediators. Examples of such cytokines are lymphokines, monokines, and traditional polypeptide hormones. Included among the cytokines are growth hormone such as human growth hormone, N-methionyl human growth hormone, and bovine growth hormone; parathyroid hormone; thyroxine; insulin; proinsulin; relaxin; prorelaxin; glycoprotein hormones such as follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), and luteinizing hormone (LH); hepatic growth factor; fibroblast growth factor; prolactin; placental lactogen; tumor necrosis factor-α and -β; mullerian-inhibiting substance; mouse gonadotropin-associated peptide; inhibin; activin; vascular endothelial growth factor; integrin; thrombopoietin (TPO); nerve growth factors such as NGF-β; platelet-growth factor; transforming growth factors (TGFs) such as TGF-α and TGF-β; insulin-like growth factor-I and -II; erythropoietin (EPO); osteoinductive factors; interferons such as interferon-α, -β, and -γ; colony stimulating factors (CSFs) such as macrophage-CSF (M-CSF); granulocyte-macrophage-CSF (GM-CSF); and granulocyte-CSF (G-CSF); interleukins (ILs) such as IL-1, IL-1a, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-11, IL-12; a tumor necrosis factor such as TNF-α or TNF-β; and other polypeptide factors including LIF and kit ligand (KL). As used herein, the term cytokine includes proteins from natural sources or from recombinant cell culture and biologically active equivalents of the native sequence cytokines.
The term “package insert” is used to refer to instructions customarily included in commercial packages of therapeutic products, that contain information about the indications, usage, dosage, administration, contraindications and/or warnings concerning the use of such therapeutic products.
The term “intracellular metabolite” refers to a compound resulting from a metabolic process or reaction inside a cell on an antibody-drug conjugate (ADC). The metabolic process or reaction may be an enzymatic process, such as proteolytic cleavage of a peptide linker of the ADC, or hydrolysis of a functional group such as a hydrazone, ester, or amide. Intracellular metabolites include, but are not limited to, antibodies and free drug which have undergone intracellular cleavage after entry, diffusion, uptake or transport into a cell.
The terms “intracellularly cleaved” and “intracellular cleavage” refer to a metabolic process or reaction inside a cell on an antibody-drug conjugate (ADC) whereby the covalent attachment, i.e. linker, between the drug moiety (D) and the antibody (Ab) is broken, resulting in the free drug dissociated from the antibody inside the cell. The cleaved moieties of the ADC are thus intracellular metabolites.
The term “bioavailability” refers to the systemic availability (i.e., blood/plasma levels) of a given amount of drug administered to a patient. Bioavailability is an absolute term that indicates measurement of both the time (rate) and total amount (extent) of drug that reaches the general circulation from an administered dosage form.
The term “cytotoxic activity” refers to a cell-killing, cytostatic or growth inhibitory effect of an ADC or an intracellular metabolite of an ADC. Cytotoxic activity may be expressed as the IC50 value, which is the concentration (molar or mass) per unit volume at which half the cells survive.
The term “alkyl” as used herein refers to a saturated linear or branched-chain monovalent hydrocarbon radical of one to twelve carbon atoms (C1-C12), wherein the alkyl radical may be optionally substituted independently with one or more substituents described below. In another embodiment, an alkyl radical is one to eight carbon atoms (C1-C8), or one to six carbon atoms (C1-C6). Examples of alkyl groups include, but are not limited to, methyl (Me, —CH3), ethyl (Et, —CH2CH3), 1-propyl (n-Pr, n-propyl, —CH2CH2CH3), 2-propyl (i-Pr, i-propyl, —CH(CH3)2), 1-butyl (n-Bu, n-butyl, —CH2CH2CH2CH3), 2-methyl-1-propyl (n-Bu, i-butyl, —CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, —CH(CH3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, —C(CH3)3), 1-pentyl (n-pentyl, —CH2CH2CH2CH2CH3), 2-pentyl (—CH(CH3)CH2CH2CH3), 3-pentyl (—CH(CH2CH3)2), 2-methyl-2-butyl (—C(CH3)2CH2CH3), 3-methyl-2-butyl (—CH(CH3)CH(CH3)2), 3-methyl-1-butyl (—CH2CH2CH(CH3)2), 2-methyl-1-butyl (—CH2CH(CH3)CH2CH3), 1-hexyl (—CH2CH2CH2CH2CH2CH3), 2-hexyl (—CH(CH3)CH2CH2CH2CH3), 3-hexyl (—CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (—C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl (—CH(CH3)CH(CH3)CH2CH3), 4-methyl-2-pentyl (—CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (—C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (—CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (—C(CH3)2CH(CH3)2), 3,3-dimethyl-2-butyl (—CH(CH3)C(CH3)3, 1-heptyl, 1-octyl, and the like.
The term “alkenyl” refers to linear or branched-chain monovalent hydrocarbon radical of two to eight carbon atoms (C2-C8) with at least one site of unsaturation, i.e., a carbon-carbon, sp2 double bond, wherein the alkenyl radical may be optionally substituted independently with one or more substituents described herein, and includes radicals having “cis” and “trans” orientations, or alternatively, “E” and “Z” orientations. Examples include, but are not limited to, ethylenyl or vinyl (—CH═CH2), allyl (—CH2CH═CH), and the like.
The term “alkynyl” refers to a linear or branched monovalent hydrocarbon radical of two to eight carbon atoms (C2-C8) with at least one site of unsaturation, i.e., a carbon-carbon, sp triple bond, wherein the alkynyl radical may be optionally substituted independently with one or more substituents described herein. Examples include, but are not limited to, ethynyl (—C≡CH), propynyl (propargyl, —CH2C≡CH), and the like.
The terms “carbocycle”, “carbocyclyl”, “carbocyclic ring” and “cycloalkyl” refer to a monovalent non-aromatic, saturated or partially unsaturated ring having 3 to 12 carbon atoms (C3-C12) as a monocyclic ring or 7 to 12 carbon atoms as a bicyclic ring. Bicyclic carbocycles having 7 to 12 atoms can be arranged, for example, as a bicyclo [4,5], [5,5], [5,6] or [6,6] system, and bicyclic carbocycles having 9 or 10 ring atoms can be arranged as a bicyclo [5,6] or [6,6] system, or as bridged systems such as bicyclo[2.2.1]heptane, bicyclo[2.2.2]octane and bicyclo[3.2.2]nonane. Examples of monocyclic carbocycles include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, 1-cyclopent-1-enyl, 1-cyclopent-2-enyl, 1-cyclopent-3-enyl, cyclohexyl, 1-cyclohex-1-enyl, 1-cyclohex-2-enyl, 1-cyclohex-3-enyl, cyclohexadienyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, and the like.
“Aryl” means a monovalent aromatic hydrocarbon radical of 6-20 carbon atoms (C6-C20) derived by the removal of one hydrogen atom from a single carbon atom of a parent aromatic ring system. Some aryl groups are represented in the exemplary structures as “Ar”. Aryl includes bicyclic radicals comprising an aromatic ring fused to a saturated, partially unsaturated ring, or aromatic carbocyclic ring. Typical aryl groups include, but are not limited to, radicals derived from benzene (phenyl), substituted benzenes, naphthalene, anthracene, biphenyl, indenyl, indanyl, 1,2-dihydronaphthalene, 1,2,3,4-tetrahydronaphthyl, and the like. Aryl groups are optionally substituted independently with one or more substituents described herein.
The terms “heterocycle,” “heterocyclyl” and “heterocyclic ring” are used interchangeably herein and refer to a saturated or a partially unsaturated (i.e., having one or more double and/or triple bonds within the ring) carbocyclic radical of 3 to 20 ring atoms in which at least one ring atom is a heteroatom selected from nitrogen, oxygen, phosphorus and sulfur, the remaining ring atoms being C, where one or more ring atoms is optionally substituted independently with one or more substituents described below. A heterocycle may be a monocycle having 3 to 7 ring members (2 to 6 carbon atoms and 1 to 4 heteroatoms selected from N, O, P, and S) or a bicycle having 7 to 10 ring members (4 to 9 carbon atoms and 1 to 6 heteroatoms selected from N, O, P, and S), for example: a bicyclo [4,5], [5,5], [5,6], or [6,6] system. Heterocycles are described in Paquette, Leo A.; “Principles of Modern Heterocyclic Chemistry” (W. A. Benjamin, New York, 1968), particularly Chapters 1, 3, 4, 6, 7, and 9; “The Chemistry of Heterocyclic Compounds, A series of Monographs” (John Wiley & Sons, New York, 1950 to present), in particular Volumes 13, 14, 16, 19, and 28; and J. Am. Chem. Soc. (1960) 82:5566. “Heterocyclyl” also includes radicals where heterocycle radicals are fused with a saturated, partially unsaturated ring, or aromatic carbocyclic or heterocyclic ring. Examples of heterocyclic rings include, but are not limited to, pyrrolidinyl, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothienyl, tetrahydropyranyl, dihydropyranyl, tetrahydrothiopyranyl, piperidino, morpholino, thiomorpholino, thioxanyl, piperazinyl, homopiperazinyl, azetidinyl, oxetanyl, thietanyl, homopiperidinyl, oxepanyl, thiepanyl, oxazepinyl, diazepinyl, thiazepinyl, 2-pyrrolinyl, 3-pyrrolinyl, indolinyl, 2H-pyranyl, 4H-pyranyl, dioxanyl, 1,3-dioxolanyl, pyrazolinyl, dithianyl, dithiolanyl, dihydropyranyl, dihydrothienyl, dihydrofuranyl, pyrazolidinylimidazolinyl, imidazolidinyl, 3-azabicyco[3.1.0]hexanyl, 3-azabicyclo[4.1.0]heptanyl, azabicyclo[2.2.2]hexanyl, 3H-indolyl quinolizinyl and N-pyridyl ureas. Spiro moieties are also included within the scope of this definition. Examples of a heterocyclic group wherein 2 ring carbon atoms are substituted with oxo (═O) moieties are pyrimidinonyl and 1,1-dioxo-thiomorpholinyl. The heterocycle groups herein are optionally substituted independently with one or more substituents described herein.
The term “heteroaryl” refers to a monovalent aromatic radical of 5-, 6-, or 7-membered rings, and includes fused ring systems (at least one of which is aromatic) of 5-20 atoms, containing one or more heteroatoms independently selected from nitrogen, oxygen, and sulfur. Examples of heteroaryl groups are pyridinyl (including, for example, 2-hydroxypyridinyl), imidazolyl, imidazopyridinyl, pyrimidinyl (including, for example, 4-hydroxypyrimidinyl), pyrazolyl, triazolyl, pyrazinyl, tetrazolyl, furyl, thienyl, isoxazolyl, thiazolyl, oxazolyl, isothiazolyl, pyrrolyl, quinolinyl, isoquinolinyl, indolyl, benzimidazolyl, benzofuranyl, cinnolinyl, indazolyl, indolizinyl, phthalazinyl, pyridazinyl, triazinyl, isoindolyl, pteridinyl, purinyl, oxadiazolyl, triazolyl, thiadiazolyl, thiadiazolyl, furazanyl, benzofurazanyl, benzothiophenyl, benzothiazolyl, benzoxazolyl, quinazolinyl, quinoxalinyl, naphthyridinyl, and furopyridinyl. Heteroaryl groups are optionally substituted independently with one or more substituents described herein.
The heterocycle or heteroaryl groups may be carbon (carbon-linked), or nitrogen (nitrogen-linked) bonded where such is possible. By way of example and not limitation, carbon bonded heterocycles or heteroaryls are bonded at position 2, 3, 4, 5, or 6 of a pyridine, position 3, 4, 5, or 6 of a pyridazine, position 2, 4, 5, or 6 of a pyrimidine, position 2, 3, 5, or 6 of a pyrazine, position 2, 3, 4, or 5 of a furan, tetrahydrofuran, thiofuran, thiophene, pyrrole or tetrahydropyrrole, position 2, 4, or 5 of an oxazole, imidazole or thiazole, position 3, 4, or 5 of an isoxazole, pyrazole, or isothiazole, position 2 or 3 of an aziridine, position 2, 3, or 4 of an azetidine, position 2, 3, 4, 5, 6, 7, or 8 of a quinoline or position 1, 3, 4, 5, 6, 7, or 8 of an isoquinoline.
By way of example and not limitation, nitrogen bonded heterocycles or heteroaryls are bonded at position 1 of an aziridine, azetidine, pyrrole, pyrrolidine, 2-pyrroline, 3-pyrroline, imidazole, imidazolidine, 2-imidazoline, 3-imidazoline, pyrazole, pyrazoline, 2-pyrazoline, 3-pyrazoline, piperidine, piperazine, indole, indoline, 1H-indazole, position 2 of a isoindole, or isoindoline, position 4 of a morpholine, and position 9 of a carbazole, or carboline.
“Alkylene” refers to a saturated, branched or straight chain or cyclic hydrocarbon radical of 1-18 carbon atoms, and having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkane. Typical alkylene radicals include, but are not limited to: methylene (—CH2—) 1,2-ethyl (—CH2CH2—), 1,3-propyl (—CH2CH2CH2—), 1,4-butyl (—CH2CH2CH2CH2—), and the like.
A “C1-C10 alkylene” is a straight chain, saturated hydrocarbon group of the formula —(CH2)1-10—. Examples of a C1-C10 alkylene include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, ocytylene, nonylene and decalene.
“Alkenylene” refers to an unsaturated, branched or straight chain or cyclic hydrocarbon radical of 2-18 carbon atoms, and having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkene. Typical alkenylene radicals include, but are not limited to: 1,2-ethylene (—CH═CH—).
“Alkynylene” refers to an unsaturated, branched or straight chain or cyclic hydrocarbon radical of 2-18 carbon atoms, and having two monovalent radical centers derived by the removal of two hydrogen atoms from the same or two different carbon atoms of a parent alkyne. Typical alkynylene radicals include, but are not limited to: acetylene (—C≡C—), propargyl (—CH2C≡C—), and 4-pentynyl (—CH2CH2CH2C≡C—).
An “arylene” is an aryl group which has two covalent bonds and can be in the ortho, meta, or para configurations as shown in the following structures:
in which the phenyl group can be unsubstituted or substituted with up to four groups including, but not limited to, —C1-C8 alkyl, —O—(C1-C8 alkyl), -aryl, —C(O)R′, —OC(O)R′, —C(O)OR′, —C(O)NH2, —C(O)NHR′, —C(O)N(R′)2—NHC(O)R′, —S(O)2R′, —S(O)R′, —OH, -halogen, —N3, —NH2, —NH(R′), —N(R′)2 and —CN; wherein each R′ is independently selected from H, —C1-C8 alkyl and aryl.
“Arylalkyl” refers to an acyclic alkyl radical in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp3 carbon atom, is replaced with an aryl radical. Typical arylalkyl groups include, but are not limited to, benzyl, 2-phenylethan-1-yl, 2-phenylethen-1-yl, naphthylmethyl, 2-naphthylethan-1-yl, 2-naphthylethen-1-yl, naphthobenzyl, 2-naphthophenylethan-1-yl and the like. The arylalkyl group comprises 6 to 20 carbon atoms, e.g. the alkyl moiety, including alkanyl, alkenyl or alkynyl groups, of the arylalkyl group is 1 to 6 carbon atoms and the aryl moiety is 5 to 14 carbon atoms.
“Heteroarylalkyl” refers to an acyclic alkyl radical in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp3 carbon atom, is replaced with a heteroaryl radical. Typical heteroarylalkyl groups include, but are not limited to, 2-benzimidazolylmethyl, 2-furylethyl, and the like. The heteroarylalkyl group comprises 6 to 20 carbon atoms, e.g. the alkyl moiety, including alkanyl, alkenyl or alkynyl groups, of the heteroarylalkyl group is 1 to 6 carbon atoms and the heteroaryl moiety is 5 to 14 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S. The heteroaryl moiety of the heteroarylalkyl group may be a monocycle having 3 to 7 ring members (2 to 6 carbon atoms or a bicycle having 7 to 10 ring members (4 to 9 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S), for example: a bicyclo [4,5], [5,5], [5,6], or [6,6] system.
The term “prodrug” as used in this application refers to a precursor or derivative form of a compound of the invention that may be less cytotoxic to cells compared to the parent compound or drug and is capable of being enzymatically or hydrolytically activated or converted into the more active parent form. See, e.g., Wilman, “Prodrugs in Cancer Chemotherapy” Biochemical Society Transactions, 14, pp. 375-382, 615th Meeting Belfast (1986) and Stella et al., “Prodrugs: A Chemical Approach to Targeted Drug Delivery,” Directed Drug Delivery, Borchardt et al., (ed.), pp. 247-267, Humana Press (1985). The prodrugs of this invention include, but are not limited to, phosphate-containing prodrugs, thiophosphate-containing prodrugs, sulfate-containing prodrugs, peptide-containing prodrugs, D-amino acid-modified prodrugs, glycosylated prodrugs, β-lactam-containing prodrugs, optionally substituted phenoxyacetamide-containing prodrugs, optionally substituted phenylacetamide-containing prodrugs, 5-fluorocytosine and other 5-fluorouridine prodrugs which can be converted into the more active cytotoxic free drug. Examples of cytotoxic drugs that can be derivatized into a prodrug form for use in this invention include, but are not limited to, compounds of the invention and chemotherapeutic agents such as described above.
A “metabolite” is a product produced through metabolism in the body of a specified compound or salt thereof. Metabolites of a compound may be identified using routine techniques known in the art and their activities determined using tests such as those described herein. Such products may result for example from the oxidation, reduction, hydrolysis, amidation, deamidation, esterification, deesterification, enzymatic cleavage, and the like, of the administered compound. Accordingly, the invention includes metabolites of compounds of the invention, including compounds produced by a process comprising contacting a compound of this invention with a mammal for a period of time sufficient to yield a metabolic product thereof.
A “liposome” is a small vesicle composed of various types of lipids, phospholipids and/or surfactant which is useful for delivery of a drug to a mammal. The components of the liposome are commonly arranged in a bilayer formation, similar to the lipid arrangement of biological membranes.
“Linker” refers to a chemical moiety comprising a covalent bond or a chain of atoms that covalently attaches an antibody to a drug moiety. In various embodiments, linkers include a divalent radical such as an alkyldiyl, an aryldiyl, a heteroaryldiyl, moieties such as: —(CR2)nO(CR2)n—, repeating units of alkyloxy (e.g. polyethylenoxy, PEG, polymethyleneoxy) and alkylamino (e.g. polyethyleneamino, Jeffamine™); and diacid ester and amides including succinate, succinamide, diglycolate, malonate, and caproamide.
The term “chiral” refers to molecules which have the property of non-superimposability of the mirror image partner, while the term “achiral” refers to molecules which are superimposable on their mirror image partner.
The term “stereoisomers” refers to compounds which have identical chemical constitution, but differ with regard to the arrangement of the atoms or groups in space.
“Diastereomer” refers to a stereoisomer with two or more centers of chirality and whose molecules are not mirror images of one another. Diastereomers have different physical properties, e.g. melting points, boiling points, spectral properties, and reactivities. Mixtures of diastereomers may separate under high resolution analytical procedures such as electrophoresis and chromatography.
“Enantiomers” refer to two stereoisomers of a compound which are non-superimposable mirror images of one another.
Stereochemical definitions and conventions used herein generally follow S. P. Parker, Ed., McGraw-Hill Dictionary of Chemical Terms (1984) McGraw-Hill Book Company, New York; and Eliel, E. and Wilen, S., Stereochemistry of Organic Compounds (1994) John Wiley & Sons, Inc., New York. Many organic compounds exist in optically active forms, i.e., they have the ability to rotate the plane of plane-polarized light. In describing an optically active compound, the prefixes D and L, or R and S, are used to denote the absolute configuration of the molecule about its chiral center(s). The prefixes d and l or (+) and (−) are employed to designate the sign of rotation of plane-polarized light by the compound, with (−) or 1 meaning that the compound is levorotatory. A compound prefixed with (+) or d is dextrorotatory. For a given chemical structure, these stereoisomers are identical except that they are mirror images of one another. A specific stereoisomer may also be referred to as an enantiomer, and a mixture of such isomers is often called an enantiomeric mixture. A 50:50 mixture of enantiomers is referred to as a racemic mixture or a racemate, which may occur where there has been no stereoselection or stereospecificity in a chemical reaction or process. The terms “racemic mixture” and “racemate” refer to an equimolar mixture of two enantiomeric species, devoid of optical activity.
The term “tautomer” or “tautomeric form” refers to structural isomers of different energies which are interconvertible via a low energy barrier. For example, proton tautomers (also known as prototropic tautomers) include interconversions via migration of a proton, such as keto-enol and imine-enamine isomerizations. Valence tautomers include interconversions by reorganization of some of the bonding electrons.
The phrase “pharmaceutically acceptable salt” as used herein, refers to pharmaceutically acceptable organic or inorganic salts of a compound of the invention. Exemplary salts include, but are not limited, to sulfate, citrate, acetate, oxalate, chloride, bromide, iodide, nitrate, bisulfate, phosphate, acid phosphate, isonicotinate, lactate, salicylate, acid citrate, tartrate, oleate, tannate, pantothenate, bitartrate, ascorbate, succinate, maleate, gentisinate, fumarate, gluconate, glucuronate, saccharate, formate, benzoate, glutamate, methanesulfonate “mesylate”, ethanesulfonate, benzenesulfonate, p-toluenesulfonate, and pamoate (i.e., 1,1′-methylene-bis(2-hydroxy-3-naphthoate)) salts. A pharmaceutically acceptable salt may involve the inclusion of another molecule such as an acetate ion, a succinate ion or other counter ion. The counter ion may be any organic or inorganic moiety that stabilizes the charge on the parent compound. Furthermore, a pharmaceutically acceptable salt may have more than one charged atom in its structure. Instances where multiple charged atoms are part of the pharmaceutically acceptable salt can have multiple counter ions. Hence, a pharmaceutically acceptable salt can have one or more charged atoms and/or one or more counter ion.
If the compound of the invention is a base, the desired pharmaceutically acceptable salt may be prepared by any suitable method available in the art, for example, treatment of the free base with an inorganic acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, methanesulfonic acid, phosphoric acid and the like, or with an organic acid, such as acetic acid, trifluoroacetic acid, maleic acid, succinic acid, mandelic acid, fumaric acid, malonic acid, pyruvic acid, oxalic acid, glycolic acid, salicylic acid, a pyranosidyl acid, such as glucuronic acid or galacturonic acid, an alpha hydroxy acid, such as citric acid or tartaric acid, an amino acid, such as aspartic acid or glutamic acid, an aromatic acid, such as benzoic acid or cinnamic acid, a sulfonic acid, such as p-toluenesulfonic acid or ethanesulfonic acid, or the like.
If the compound of the invention is an acid, the desired pharmaceutically acceptable salt may be prepared by any suitable method, for example, treatment of the free acid with an inorganic or organic base, such as an amine (primary, secondary or tertiary), an alkali metal hydroxide or alkaline earth metal hydroxide, or the like. Illustrative examples of suitable salts include, but are not limited to, organic salts derived from amino acids, such as glycine and arginine, ammonia, primary, secondary, and tertiary amines, and cyclic amines, such as piperidine, morpholine and piperazine, and inorganic salts derived from sodium, calcium, potassium, magnesium, manganese, iron, copper, zinc, aluminum and lithium.
The phrase “pharmaceutically acceptable” indicates that the substance or composition must be compatible chemically and/or toxicologically, with the other ingredients comprising a formulation, and/or the mammal being treated therewith.
A “solvate” refers to an association or complex of one or more solvent molecules and a compound of the invention. Examples of solvents that form solvates include, but are not limited to, water, isopropanol, ethanol, methanol, DMSO, ethyl acetate, acetic acid, and ethanolamine. The term “hydrate” refers to the complex where the solvent molecule is water.
The term “protecting group” refers to a substituent that is commonly employed to block or protect a particular functionality while reacting other functional groups on the compound. For example, an “amino-protecting group” is a substituent attached to an amino group that blocks or protects the amino functionality in the compound. Suitable amino-protecting groups include acetyl, trifluoroacetyl, t-butoxycarbonyl (BOC), benzyloxycarbonyl (CBZ) and 9-fluorenylmethylenoxycarbonyl (Fmoc). Similarly, a “hydroxy-protecting group” refers to a substituent of a hydroxy group that blocks or protects the hydroxy functionality. Suitable protecting groups include acetyl and silyl. A “carboxy-protecting group” refers to a substituent of the carboxy group that blocks or protects the carboxy functionality. Common carboxy-protecting groups include phenylsulfonylethyl, cyanoethyl, 2-(trimethylsilyl)ethyl, 2-(trimethylsilyl)ethoxymethyl, 2-(p-toluenesulfonyl)ethyl, 2-(p-nitrophenylsulfenyl)ethyl, 2-(diphenylphosphino)-ethyl, nitroethyl and the like. For a general description of protecting groups and their use, see T. W. Greene, Protective Groups in Organic Synthesis, John Wiley & Sons, New York, 1991.
“Leaving group” refers to a functional group that can be substituted by another functional group. Certain leaving groups are well known in the art, and examples include, but are not limited to, a halide (e.g., chloride, bromide, iodide), methanesulfonyl (mesyl), p-toluenesulfonyl (tosyl), trifluoromethylsulfonyl (triflate), and trifluoromethylsulfonate.
Abbreviations
Linker Components:
MC=6-maleimidocaproyl
Val-Cit or “vc”=valine-citrulline (an exemplary dipeptide in a protease cleavable linker)
Citrulline=2-amino-5-ureido pentanoic acid
PAB=p-aminobenzyloxycarbonyl (an example of a “self immolative” linker component)
Me-Val-Cit=N-methyl-valine-citrulline (wherein the linker peptide bond has been modified to prevent its cleavage by cathepsin B)
MC(PEG)6-OH=maleimidocaproyl-polyethylene glycol (can be attached to antibody cysteines).
MMAE=mono-methyl auristatin E (MW 718)
MMAF=variant of auristatin E (MMAE) with a phenylalanine at the C-terminus of the drug (MW 731.5)
MMAF-DMAEA=MMAF with DMAEA (dimethylaminoethylamine) in an amide linkage to the C-terminal phenylalanine (MW 801.5)
MMAF-TEG=MMAF with tetraethylene glycol esterified to the phenylalanine
MMAF-NtBu=N-t-butyl, attached as an amide to C-terminus of MMAF
DM1=N(2′)-deacetyl-N(2′)-(3-mercapto-1-oxopropyl)-maytansine
DM3=N(2′)-deacetyl-N2-(4-mercapto-1-oxopentyl)-maytansine
DM4=N(2′)-deacetyl-N2-(4-mercapto-4-methyl-1-oxopentyl)-maytansine
Further abbreviations are as follows: AE is auristatin E, Boc is N-(t-butoxycarbonyl), cit is citrulline, dap is dolaproine, DCC is 1,3-dicyclohexylcarbodiimide, DCM is dichloromethane, DEA is diethylamine, DEAD is diethylazodicarboxylate, DEPC is diethylphosphorylcyanidate, DIAD is diisopropylazodicarboxylate, DIEA is N,N-diisopropylethylamine, dil is dolaisoleucine, DMA is dimethylacetamide, DMAP is 4-dimethylaminopyridine, DME is ethyleneglycol dimethyl ether (or 1,2-dimethoxyethane), DMF is N,N-dimethylformamide, DMSO is dimethylsulfoxide, doe is dolaphenine, dov is N,N-dimethylvaline, DTNB is 5,5′-dithiobis(2-nitrobenzoic acid), DTPA is diethylenetriaminepentaacetic acid, DTT is dithiothreitol, EDCI is 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, EEDQ is 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline, ES-MS is electrospray mass spectrometry, EtOAc is ethyl acetate, Fmoc is N-(9-fluorenylmethoxycarbonyl), gly is glycine, HATU is O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate, HOBt is 1-hydroxybenzotriazole, HPLC is high pressure liquid chromatography, ile is isoleucine, lys is lysine, MeCN(CH3CN) is acetonitrile, MeOH is methanol, Mtr is 4-anisyldiphenylmethyl (or 4-methoxytrityl), nor is (1S,2R)-(+)-norephedrine, PBS is phosphate-buffered saline (pH 7.4), PEG is polyethylene glycol, Ph is phenyl, Pnp is p-nitrophenyl, MC is 6-maleimidocaproyl, phe is L-phenylalanine, PyBrop is bromo tris-pyrrolidino phosphonium hexafluorophosphate, SEC is size-exclusion chromatography, Su is succinimide, TFA is trifluoroacetic acid, TLC is thin layer chromatography, UV is ultraviolet, and val is valine.
A “free cysteine amino acid” refers to a cysteine amino acid residue which has been engineered into a parent antibody, has a thiol functional group (—SH), and is not paired as an intramolecular or intermolecular disulfide bridge.
The term “thiol reactivity value” is a quantitative characterization of the reactivity of free cysteine amino acids. The thiol reactivity value is the percentage of a free cysteine amino acid in a cysteine engineered antibody which reacts with a thiol-reactive reagent, and converted to a maximum value of 1. For example, a free cysteine amino acid on a cysteine engineered antibody which reacts in 100% yield with a thiol-reactive reagent, such as a biotin-maleimide reagent, to form a biotin-labelled antibody has a thiol reactivity value of 1.0. Another cysteine amino acid engineered into the same or different parent antibody which reacts in 80% yield with a thiol-reactive reagent has a thiol reactivity value of 0.8. Another cysteine amino acid engineered into the same or different parent antibody which fails totally to react with a thiol-reactive reagent has a thiol reactivity value of 0. Determination of the thiol reactivity value of a particular cysteine may be conducted by ELISA assay, mass spectroscopy, liquid chromatography, autoradiography, or other quantitative analytical tests.
A “parent antibody” is an antibody comprising an amino acid sequence from which one or more amino acid residues are replaced by one or more cysteine residues. The parent antibody may comprise a native or wild type sequence. The parent antibody may have pre-existing amino acid sequence modifications (such as additions, deletions and/or substitutions) relative to other native, wild type, or modified forms of an antibody. A parent antibody may be directed against a target antigen of interest, e.g. a biologically important polypeptide. Antibodies directed against nonpolypeptide antigens (such as tumor-associated glycolipid antigens; see U.S. Pat. No. 5,091,178) are also contemplated.
A. Anti-TAHO Antibodies
In one embodiment, the present invention provides anti-TAHO antibodies which may find use herein as therapeutic agents. Exemplary antibodies include polyclonal, monoclonal, humanized, bispecific, and heteroconjugate antibodies.
1. Polyclonal Antibodies
Polyclonal antibodies are preferably raised in animals by multiple subcutaneous (sc) or intraperitoneal (ip) injections of the relevant antigen and an adjuvant. It may be useful to conjugate the relevant antigen (especially when synthetic peptides are used) to a protein that is immunogenic in the species to be immunized. For example, the antigen can be conjugated to keyhole limpet hemocyanin (KLH), serum albumin, bovine thyroglobulin, or soybean trypsin inhibitor, using a bifunctional or derivatizing agent, e.g., maleimidobenzoyl sulfosuccinimide ester (conjugation through cysteine residues), N-hydroxysuccinimide (through lysine residues), glutaraldehyde, succinic anhydride, SOCl2, or R1N═C═NR, where R and R1 are different alkyl groups.
Animals are immunized against the antigen, immunogenic conjugates, or derivatives by combining, e.g., 100 μg or 5 μg of the protein or conjugate (for rabbits or mice, respectively) with 3 volumes of Freund's complete adjuvant and injecting the solution intradermally at multiple sites. One month later, the animals are boosted with ⅕ to 1/10 the original amount of peptide or conjugate in Freund's complete adjuvant by subcutaneous injection at multiple sites. Seven to 14 days later, the animals are bled and the serum is assayed for antibody titer. Animals are boosted until the titer plateaus. Conjugates also can be made in recombinant cell culture as protein fusions. Also, aggregating agents such as alum are suitably used to enhance the immune response.
2. Monoclonal Antibodies
Monoclonal antibodies may be made using the hybridoma method first described by Kohler et al., Nature, 256:495 (1975), or may be made by recombinant DNA methods (U.S. Pat. No. 4,816,567).
In the hybridoma method, a mouse or other appropriate host animal, such as a hamster, is immunized as described above to elicit lymphocytes that produce or are capable of producing antibodies that will specifically bind to the protein used for immunization. Alternatively, lymphocytes may be immunized in vitro. After immunization, lymphocytes are isolated and then fused with a myeloma cell line using a suitable fusing agent, such as polyethylene glycol, to form a hybridoma cell (Goding, Monoclonal Antibodies: Principles and Practice, pp. 59-103 (Academic Press, 1986)).
The hybridoma cells thus prepared are seeded and grown in a suitable culture medium which medium preferably contains one or more substances that inhibit the growth or survival of the unfused, parental myeloma cells (also referred to as fusion partner). For example, if the parental myeloma cells lack the enzyme hypoxanthine guanine phosphoribosyl transferase (HGPRT or HPRT), the selective culture medium for the hybridomas typically will include hypoxanthine, aminopterin, and thymidine (HAT medium), which substances prevent the growth of HGPRT-deficient cells.
Preferred fusion partner myeloma cells are those that fuse efficiently, support stable high-level production of antibody by the selected antibody-producing cells, and are sensitive to a selective medium that selects against the unfused parental cells. Preferred myeloma cell lines are murine myeloma lines, such as those derived from MOPC-21 and MPC-11 mouse tumors available from the Salk Institute Cell Distribution Center, San Diego, Calif. USA, and SP-2 and derivatives e.g., X63-Ag8-653 cells available from the American Type Culture Collection, Manassas, Va., USA. Human myeloma and mouse-human heteromyeloma cell lines also have been described for the production of human monoclonal antibodies (Kozbor, J. Immunol., 133:3001 (1984); and Brodeur et al., Monoclonal Antibody Production Techniques and Applications, pp. 51-63 (Marcel Dekker, Inc., New York, 1987)).
Culture medium in which hybridoma cells are growing is assayed for production of monoclonal antibodies directed against the antigen. Preferably, the binding specificity of monoclonal antibodies produced by hybridoma cells is determined by immunoprecipitation or by an in vitro binding assay, such as radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA).
The binding affinity of the monoclonal antibody can, for example, be determined by the Scatchard analysis described in Munson et al., Anal. Biochem., 107:220 (1980).
Once hybridoma cells that produce antibodies of the desired specificity, affinity, and/or activity are identified, the clones may be subcloned by limiting dilution procedures and grown by standard methods (Goding, Monoclonal Antibodies: Principles and Practice, pp. 59-103 (Academic Press, 1986)). Suitable culture media for this purpose include, for example, D-MEM or RPMI-1640 medium. In addition, the hybridoma cells may be grown in vivo as ascites tumors in an animal e.g., by i.p. injection of the cells into mice.
The monoclonal antibodies secreted by the subclones are suitably separated from the culture medium, ascites fluid, or serum by conventional antibody purification procedures such as, for example, affinity chromatography (e.g., using protein A or protein G-Sepharose) or ion-exchange chromatography, hydroxylapatite chromatography, gel electrophoresis, dialysis, etc.
DNA encoding the monoclonal antibodies is readily isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of murine antibodies). The hybridoma cells serve as a preferred source of such DNA. Once isolated, the DNA may be placed into expression vectors, which are then transfected into host cells such as E. coli cells, simian COS cells, Chinese Hamster Ovary (CHO) cells, or myeloma cells that do not otherwise produce antibody protein, to obtain the synthesis of monoclonal antibodies in the recombinant host cells. Review articles on recombinant expression in bacteria of DNA encoding the antibody include Skerra et al., Curr. Opinion in Immunol., 5:256-262 (1993) and Pluckthun, Immunol. Revs. 130:151-188 (1992).
In a further embodiment, monoclonal antibodies or antibody fragments can be isolated from antibody phage libraries generated using the techniques described in McCafferty et al., Nature, 348:552-554 (1990). Clackson et al., Nature, 352:624-628 (1991) and Marks et al., J. Mol. Biol., 222:581-597 (1991) describe the isolation of murine and human antibodies, respectively, using phage libraries. Subsequent publications describe the production of high affinity (nM range) human antibodies by chain shuffling (Marks et al., Bio/Technology, 10:779-783 (1992)), as well as combinatorial infection and in vivo recombination as a strategy for constructing very large phage libraries (Waterhouse et al., Nuc. Acids. Res. 21:2265-2266 (1993)). Thus, these techniques are viable alternatives to traditional monoclonal antibody hybridoma techniques for isolation of monoclonal antibodies.
The DNA that encodes the antibody may be modified to produce chimeric or fusion antibody polypeptides, for example, by substituting human heavy chain and light chain constant domain (CH and CL) sequences for the homologous murine sequences (U.S. Pat. No. 4,816,567; and Morrison, et al., Proc. Natl. Acad. Sci. USA, 81:6851 (1984)), or by fusing the immunoglobulin coding sequence with all or part of the coding sequence for a non-immunoglobulin polypeptide (heterologous polypeptide). The non-immunoglobulin polypeptide sequences can substitute for the constant domains of an antibody, or they are substituted for the variable domains of one antigen-combining site of an antibody to create a chimeric bivalent antibody comprising one antigen-combining site having specificity for an antigen and another antigen-combining site having specificity for a different antigen.
3. Human and Humanized Antibodies
The anti-TAHO antibodies of the invention may further comprise humanized antibodies or human antibodies. Humanized forms of non-human (e.g., murine) antibodies are chimeric immunoglobulins, immunoglobulin chains or fragments thereof (such as Fv, Fab, Fab′, F(ab′)2 or other antigen-binding subsequences of antibodies) which contain minimal sequence derived from non-human immunoglobulin. Humanized antibodies include human immunoglobulins (recipient antibody) in which residues from a complementary determining region (CDR) of the recipient are replaced by residues from a CDR of a non-human species (donor antibody) such as mouse, rat or rabbit having the desired specificity, affinity and capacity. In some instances, Fv framework residues of the human immunoglobulin are replaced by corresponding non-human residues. Humanized antibodies may also comprise residues which are found neither in the recipient antibody nor in the imported CDR or framework sequences. In general, the humanized antibody will comprise substantially all of at least one, and typically two, variable domains, in which all or substantially all of the CDR regions correspond to those of a non-human immunoglobulin and all or substantially all of the FR regions are those of a human immunoglobulin consensus sequence. The humanized antibody optimally also will comprise at least a portion of an immunoglobulin constant region (Fc), typically that of a human immunoglobulin [Jones et al., Nature, 321:522-525 (1986); Riechmann et al., Nature, 332:323-329 (1988); and Presta, Curr. Op. Struct. Biol., 2:593-596 (1992)].
Methods for humanizing non-human antibodies are well known in the art. Generally, a humanized antibody has one or more amino acid residues introduced into it from a source which is non-human. These non-human amino acid residues are often referred to as “import” residues, which are typically taken from an “import” variable domain. Humanization can be essentially performed following the method of Winter and co-workers [Jones et al., Nature, 321:522-525 (1986); Riechmann et al., Nature, 332:323-327 (1988); Verhoeyen et al., Science, 239:1534-1536 (1988)], by substituting rodent CDRs or CDR sequences for the corresponding sequences of a human antibody. Accordingly, such “humanized” antibodies are chimeric antibodies (U.S. Pat. No. 4,816,567), wherein substantially less than an intact human variable domain has been substituted by the corresponding sequence from a non-human species. In practice, humanized antibodies are typically human antibodies in which some CDR residues and possibly some FR residues are substituted by residues from analogous sites in rodent antibodies.
The choice of human variable domains, both light and heavy, to be used in making the humanized antibodies is very important to reduce antigenicity and HAMA response (human anti-mouse antibody) when the antibody is intended for human therapeutic use. According to the so-called “best-fit” method, the sequence of the variable domain of a rodent antibody is screened against the entire library of known human variable domain sequences. The human V domain sequence which is closest to that of the rodent is identified and the human framework region (FR) within it accepted for the humanized antibody (Sims et al., J. Immunol. 151:2296 (1993); Chothia et al., J. Mol. Biol., 196:901 (1987)). Another method uses a particular framework region derived from the consensus sequence of all human antibodies of a particular subgroup of light or heavy chains. The same framework may be used for several different humanized antibodies (Carter et al., Proc. Natl. Acad. Sci. USA, 89:4285 (1992); Presta et al., J. Immunol. 151:2623 (1993)).
It is further important that antibodies be humanized with retention of high binding affinity for the antigen and other favorable biological properties. To achieve this goal, according to a preferred method, humanized antibodies are prepared by a process of analysis of the parental sequences and various conceptual humanized products using three-dimensional models of the parental and humanized sequences. Three-dimensional immunoglobulin models are commonly available and are familiar to those skilled in the art. Computer programs are available which illustrate and display probable three-dimensional conformational structures of selected candidate immunoglobulin sequences. Inspection of these displays permits analysis of the likely role of the residues in the functioning of the candidate immunoglobulin sequence, i.e., the analysis of residues that influence the ability of the candidate immunoglobulin to bind its antigen. In this way, FR residues can be selected and combined from the recipient and import sequences so that the desired antibody characteristic, such as increased affinity for the target antigen(s), is achieved. In general, the hypervariable region residues are directly and most substantially involved in influencing antigen binding.
Various forms of a humanized anti-TAHO antibody are contemplated. For example, the humanized antibody may be an antibody fragment, such as a Fab, which is optionally conjugated with one or more cytotoxic agent(s) in order to generate an immunoconjugate. Alternatively, the humanized antibody may be an intact antibody, such as an intact IgG1 antibody.
As an alternative to humanization, human antibodies can be generated. For example, it is now possible to produce transgenic animals (e.g., mice) that are capable, upon immunization, of producing a full repertoire of human antibodies in the absence of endogenous immunoglobulin production. For example, it has been described that the homozygous deletion of the antibody heavy-chain joining region (JH) gene in chimeric and germ-line mutant mice results in complete inhibition of endogenous antibody production. Transfer of the human germ-line immunoglobulin gene array into such germ-line mutant mice will result in the production of human antibodies upon antigen challenge. See, e.g., Jakobovits et al., Proc. Natl. Acad. Sci. USA, 90:2551 (1993); Jakobovits et al., Nature, 362:255-258 (1993); Bruggemann et al., Year in Immuno. 7:33 (1993); U.S. Pat. Nos. 5,545,806, 5,569,825, 5,591,669 (all of GenPharm); 5,545,807; and WO 97/17852.
Alternatively, phage display technology (McCafferty et al., Nature 348:552-553 [1990]) can be used to produce human antibodies and antibody fragments in vitro, from immunoglobulin variable (V) domain gene repertoires from unimmunized donors. According to this technique, antibody V domain genes are cloned in-frame into either a major or minor coat protein gene of a filamentous bacteriophage, such as M13 or fd, and displayed as functional antibody fragments on the surface of the phage particle. Because the filamentous particle contains a single-stranded DNA copy of the phage genome, selections based on the functional properties of the antibody also result in selection of the gene encoding the antibody exhibiting those properties. Thus, the phage mimics some of the properties of the B-cell. Phage display can be performed in a variety of formats, reviewed in, e.g., Johnson, Kevin S, and Chiswell, David J., Current Opinion in Structural Biology 3:564-571 (1993). Several sources of V-gene segments can be used for phage display. Clackson et al., Nature, 352:624-628 (1991) isolated a diverse array of anti-oxazolone antibodies from a small random combinatorial library of V genes derived from the spleens of immunized mice. A repertoire of V genes from unimmunized human donors can be constructed and antibodies to a diverse array of antigens (including self-antigens) can be isolated essentially following the techniques described by Marks et al., J. Mol. Biol. 222:581-597 (1991), or Griffith et al., EMBO J. 12:725-734 (1993). See, also, U.S. Pat. Nos. 5,565,332 and 5,573,905.
As discussed above, human antibodies may also be generated by in vitro activated B cells (see U.S. Pat. Nos. 5,567,610 and 5,229,275).
4. Antibody Fragments
In certain circumstances there are advantages of using antibody fragments, rather than whole antibodies. The smaller size of the fragments allows for rapid clearance, and may lead to improved access to solid tumors.
Various techniques have been developed for the production of antibody fragments. Traditionally, these fragments were derived via proteolytic digestion of intact antibodies (see, e.g., Morimoto et al., Journal of Biochemical and Biophysical Methods 24:107-117 (1992); and Brennan et al., Science, 229:81 (1985)). However, these fragments can now be produced directly by recombinant host cells. Fab, Fv and ScFv antibody fragments can all be expressed in and secreted from E. coli, thus allowing the facile production of large amounts of these fragments. Antibody fragments can be isolated from the antibody phage libraries discussed above. Alternatively, Fab′-SH fragments can be directly recovered from E. coli and chemically coupled to form F(ab′)2 fragments (Carter et al., Bio/Technology 10:163-167 (1992)). According to another approach, F(ab′)2 fragments can be isolated directly from recombinant host cell culture. Fab and F(ab′)2 fragment with increased in vivo half-life comprising a salvage receptor binding epitope residues are described in U.S. Pat. No. 5,869,046. Other techniques for the production of antibody fragments will be apparent to the skilled practitioner. In other embodiments, the antibody of choice is a single chain Fv fragment (scFv). See WO 93/16185; U.S. Pat. No. 5,571,894; and U.S. Pat. No. 5,587,458. Fv and sFv are the only species with intact combining sites that are devoid of constant regions; thus, they are suitable for reduced nonspecific binding during in vivo use. sFv fusion proteins may be constructed to yield fusion of an effector protein at either the amino or the carboxy terminus of an sFv. See Antibody Engineering, ed. Borrebaeck, supra. The antibody fragment may also be a “linear antibody”, e.g., as described in U.S. Pat. No. 5,641,870 for example. Such linear antibody fragments may be monospecific or bispecific.
5. Bispecific Antibodies
Bispecific antibodies are antibodies that have binding specificities for at least two different epitopes. Exemplary bispecific antibodies may bind to two different epitopes of a TAHO protein as described herein. Other such antibodies may combine a TAHO binding site with a binding site for another protein. Alternatively, an anti-TAHO arm may be combined with an arm which binds to a triggering molecule on a leukocyte such as a T-cell receptor molecule (e.g. CD3), or Fc receptors for IgG (FcγR), such as FcγRI (CD64), FcγRII (CD32) and FcγRIII (CD16), so as to focus and localize cellular defense mechanisms to the TAHO-expressing cell. Bispecific antibodies may also be used to localize cytotoxic agents to cells which express TAHO. These antibodies possess a TAHO-binding arm and an arm which binds the cytotoxic agent (e.g., saporin, anti-interferon-α, vinca alkaloid, ricin A chain, methotrexate or radioactive isotope hapten). Bispecific antibodies can be prepared as full length antibodies or antibody fragments (e.g., F(ab′)2 bispecific antibodies).
WO 96/16673 describes a bispecific anti-ErbB2/anti-FcγRIII antibody and U.S. Pat. No. 5,837,234 discloses a bispecific anti-ErbB2/anti-FcγRI antibody. A bispecific anti-ErbB2/Fcα antibody is shown in WO98/02463. U.S. Pat. No. 5,821,337 teaches a bispecific anti-ErbB2/anti-CD3 antibody.
Methods for making bispecific antibodies are known in the art. Traditional production of full length bispecific antibodies is based on the co-expression of two immunoglobulin heavy chain-light chain pairs, where the two chains have different specificities (Millstein et al., Nature 305:537-539 (1983)). Because of the random assortment of immunoglobulin heavy and light chains, these hybridomas (quadromas) produce a potential mixture of 10 different antibody molecules, of which only one has the correct bispecific structure. Purification of the correct molecule, which is usually done by affinity chromatography steps, is rather cumbersome, and the product yields are low. Similar procedures are disclosed in WO 93/08829, and in Traunecker et al., EMBO J. 10:3655-3659 (1991).
According to a different approach, antibody variable domains with the desired binding specificities (antibody-antigen combining sites) are fused to immunoglobulin constant domain sequences. Preferably, the fusion is with an Ig heavy chain constant domain, comprising at least part of the hinge, CH2, and CH3 regions. It is preferred to have the first heavy-chain constant region (CH1) containing the site necessary for light chain bonding, present in at least one of the fusions. DNAs encoding the immunoglobulin heavy chain fusions and, if desired, the immunoglobulin light chain, are inserted into separate expression vectors, and are co-transfected into a suitable host cell. This provides for greater flexibility in adjusting the mutual proportions of the three polypeptide fragments in embodiments when unequal ratios of the three polypeptide chains used in the construction provide the optimum yield of the desired bispecific antibody. It is, however, possible to insert the coding sequences for two or all three polypeptide chains into a single expression vector when the expression of at least two polypeptide chains in equal ratios results in high yields or when the ratios have no significant affect on the yield of the desired chain combination.
In a preferred embodiment of this approach, the bispecific antibodies are composed of a hybrid immunoglobulin heavy chain with a first binding specificity in one arm, and a hybrid immunoglobulin heavy chain-light chain pair (providing a second binding specificity) in the other arm. It was found that this asymmetric structure facilitates the separation of the desired bispecific compound from unwanted immunoglobulin chain combinations, as the presence of an immunoglobulin light chain in only one half of the bispecific molecule provides for a facile way of separation. This approach is disclosed in WO 94/04690. For further details of generating bispecific antibodies see, for example, Suresh et al., Methods in Enzmmology 121:210 (1986).
According to another approach described in U.S. Pat. No. 5,731,168, the interface between a pair of antibody molecules can be engineered to maximize the percentage of heterodimers which are recovered from recombinant cell culture. The preferred interface comprises at least a part of the CH3 domain. In this method, one or more small amino acid side chains from the interface of the first antibody molecule are replaced with larger side chains (e.g., tyrosine or tryptophan). Compensatory “cavities” of identical or similar size to the large side chain(s) are created on the interface of the second antibody molecule by replacing large amino acid side chains with smaller ones (e.g., alanine or threonine). This provides a mechanism for increasing the yield of the heterodimer over other unwanted end-products such as homodimers.
Bispecific antibodies include cross-linked or “heteroconjugate” antibodies. For example, one of the antibodies in the heteroconjugate can be coupled to avidin, the other to biotin. Such antibodies have, for example, been proposed to target immune system cells to unwanted cells (U.S. Pat. No. 4,676,980), and for treatment of HIV infection (WO 91/00360, WO 92/200373, and EP 03089). Heteroconjugate antibodies may be made using any convenient cross-linking methods. Suitable cross-linking agents are well known in the art, and are disclosed in U.S. Pat. No. 4,676,980, along with a number of cross-linking techniques.
Techniques for generating bispecific antibodies from antibody fragments have also been described in the literature. For example, bispecific antibodies can be prepared using chemical linkage. Brennan et al., Science 229:81 (1985) describe a procedure wherein intact antibodies are proteolytically cleaved to generate F(ab′)2 fragments. These fragments are reduced in the presence of the dithiol complexing agent, sodium arsenite, to stabilize vicinal dithiols and prevent intermolecular disulfide formation. The Fab′ fragments generated are then converted to thionitrobenzoate (TNB) derivatives. One of the Fab′-TNB derivatives is then reconverted to the Fab′-thiol by reduction with mercaptoethylamine and is mixed with an equimolar amount of the other Fab′-TNB derivative to form the bispecific antibody. The bispecific antibodies produced can be used as agents for the selective immobilization of enzymes.
Recent progress has facilitated the direct recovery of Fab′-SH fragments from E. coli, which can be chemically coupled to form bispecific antibodies. Shalaby et al., J. Exp. Med. 175: 217-225 (1992) describe the production of a fully humanized bispecific antibody F(ab′)2 molecule. Each Fab′ fragment was separately secreted from E. coli and subjected to directed chemical coupling in vitro to form the bispecific antibody. The bispecific antibody thus formed was able to bind to cells overexpressing the ErbB2 receptor and normal human T cells, as well as trigger the lytic activity of human cytotoxic lymphocytes against human breast tumor targets.
Various techniques for making and isolating bispecific antibody fragments directly from recombinant cell culture have also been described. For example, bispecific antibodies have been produced using leucine zippers. Kostelny et al., J. Immunol. 148(5):1547-1553 (1992). The leucine zipper peptides from the Fos and Jun proteins were linked to the Fab′ portions of two different antibodies by gene fusion. The antibody homodimers were reduced at the hinge region to form monomers and then re-oxidized to form the antibody heterodimers. This method can also be utilized for the production of antibody homodimers. The “diabody” technology described by Hollinger et al., Proc. Natl. Acad. Sci. USA 90:6444-6448 (1993) has provided an alternative mechanism for making bispecific antibody fragments. The fragments comprise a VH connected to a VL by a linker which is too short to allow pairing between the two domains on the same chain. Accordingly, the VH and VL domains of one fragment are forced to pair with the complementary VL and VH domains of another fragment, thereby forming two antigen-binding sites. Another strategy for making bispecific antibody fragments by the use of single-chain Fv (sFv) dimers has also been reported. See Gruber et al., J. Immunol., 152:5368 (1994).
Antibodies with more than two valencies are contemplated. For example, trispecific antibodies can be prepared. Tutt et al., J. Immunol. 147:60 (1991).
6. Heteroconjugate Antibodies
Heteroconjugate antibodies are also within the scope of the present invention. Heteroconjugate antibodies are composed of two covalently joined antibodies. Such antibodies have, for example, been proposed to target immune system cells to unwanted cells [U.S. Pat. No. 4,676,980], and for treatment of HIV infection [WO 91/00360; WO 92/200373; EP 03089]. It is contemplated that the antibodies may be prepared in vitro using known methods in synthetic protein chemistry, including those involving crosslinking agents. For example, immunotoxins may be constructed using a disulfide exchange reaction or by forming a thioether bond. Examples of suitable reagents for this purpose include iminothiolate and methyl-4-mercaptobutyrimidate and those disclosed, for example, in U.S. Pat. No. 4,676,980.
7. Multivalent Antibodies
A multivalent antibody may be internalized (and/or catabolized) faster than a bivalent antibody by a cell expressing an antigen to which the antibodies bind. The antibodies of the present invention can be multivalent antibodies (which are other than of the IgM class) with three or more antigen binding sites (e.g. tetravalent antibodies), which can be readily produced by recombinant expression of nucleic acid encoding the polypeptide chains of the antibody. The multivalent antibody can comprise a dimerization domain and three or more antigen binding sites. The preferred dimerization domain comprises (or consists of) an Fc region or a hinge region. In this scenario, the antibody will comprise an Fc region and three or more antigen binding sites amino-terminal to the Fc region. The preferred multivalent antibody herein comprises (or consists of) three to about eight, but preferably four, antigen binding sites. The multivalent antibody comprises at least one polypeptide chain (and preferably two polypeptide chains), wherein the polypeptide chain(s) comprise two or more variable domains. For instance, the polypeptide chain(s) may comprise VD1-(X1)n-VD2-(X2)n-Fc, wherein VD1 is a first variable domain, VD2 is a second variable domain, Fc is one polypeptide chain of an Fc region, X1 and X2 represent an amino acid or polypeptide, and n is 0 or 1. For instance, the polypeptide chain(s) may comprise: VH-CH1-flexible linker-VH-CH1-Fc region chain; or VH-CH1-VH-CH1-Fc region chain. The multivalent antibody herein preferably further comprises at least two (and preferably four) light chain variable domain polypeptides. The multivalent antibody herein may, for instance, comprise from about two to about eight light chain variable domain polypeptides. The light chain variable domain polypeptides contemplated here comprise a light chain variable domain and, optionally, further comprise a CL domain.
8. Effector Function Engineering
It may be desirable to modify the antibody of the invention with respect to effector function, e.g., so as to enhance antigen-dependent cell-mediated cyotoxicity (ADCC) and/or complement dependent cytotoxicity (CDC) of the antibody. This may be achieved by introducing one or more amino acid substitutions in an Fc region of the antibody. Alternatively or additionally, cysteine residue(s) may be introduced in the Fc region, thereby allowing interchain disulfide bond formation in this region. The homodimeric antibody thus generated may have improved internalization capability and/or increased complement-mediated cell killing and antibody-dependent cellular cytotoxicity (ADCC). See Caron et al., J. Exp Med. 176:1191-1195 (1992) and Shopes, B. J. Immunol. 148:2918-2922 (1992). Homodimeric antibodies with enhanced anti-tumor activity may also be prepared using heterobifunctional cross-linkers as described in Wolff et al., Cancer Research 53:2560-2565 (1993). Alternatively, an antibody can be engineered which has dual Fc regions and may thereby have enhanced complement lysis and ADCC capabilities. See Stevenson et al., Anti-Cancer Drug Design 3:219-230 (1989). To increase the serum half life of the antibody, one may incorporate a salvage receptor binding epitope into the antibody (especially an antibody fragment) as described in U.S. Pat. No. 5,739,277, for example. As used herein, the term “salvage receptor binding epitope” refers to an epitope of the Fc region of an IgG molecule (e.g., IgG1, IgG2, IgG3, or IgG4) that is responsible for increasing the in vivo serum half-life of the IgG molecule.
9. Immunoconjugates
The invention also pertains to immunoconjugates (interchangeably referred to as “antibody-drug conjugates,” or “ADCs”) comprising an antibody conjugated to a cytotoxic agent such as a chemotherapeutic agent, a growth inhibitory agent, a toxin (e.g., an enzymatically active toxin of bacterial, fungal, plant, or animal origin, or fragments thereof), or a radioactive isotope (i.e., a radioconjugate).
In certain embodiments, an immunoconjugate comprises an antibody and a chemotherapetuic agent or other toxin. Chemotherapeutic agents useful in the generation of such immunoconjugates have been described above. Enzymatically active toxins and fragments thereof that can be used include diphtheria A chain, nonbinding active fragments of diphtheria toxin, exotoxin A chain (from Pseudomonas aeruginosa), ricin A chain, abrin A chain, modeccin A chain, alpha-sarcin, Aleurites fordii proteins, dianthin proteins, Phytolaca americana proteins (PAPI, PAPII, and PAP-S), momordica charantia inhibitor, curcin, crotin, sapaonaria officinalis inhibitor, gelonin, mitogellin, restrictocin, phenomycin, enomycin, and the tricothecenes. A variety of radionuclides are available for the production of radioconjugated antibodies. Examples include 212Bi, 131I, 131In, 90Y, and 186Re. Conjugates of the antibody and cytotoxic agent are made using a variety of bifunctional protein-coupling agents such as N-succinimidyl-3-(2-pyridyldithiol) propionate (SPDP), iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCL), active esters (such as disuccinimidyl suberate), aldehydes (such as glutareldehyde), bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as tolyene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene). For example, a ricin immunotoxin can be prepared as described in Vitetta et al., Science, 238: 1098 (1987). Carbon-14-labeled 1-isothiocyanatobenzyl-3-methyldiethylene triaminepentaacetic acid (MX-DTPA) is an exemplary chelating agent for conjugation of radionucleotide to the antibody. See WO94/11026.
Conjugates of an antibody and one or more small molecule toxins, such as a calicheamicin, auristatin peptides, such as monomethylauristatin (MMAE) (synthetic analog of dolastatin), maytansinoids, such as DM1, a trichothene, and CC1065, and the derivatives of these toxins that have toxin activity, are also contemplated herein.
An immunoconjugate (or “antibody-drug conjugate” (“ADC”)) of the invention may be of Formula I, below, wherein an antibody is conjugated (i.e., covalently attached) to one or more drug moieties (D) through an optional linker (L). ADCs may include thioMAb drug conjugates (“TDC”).
Ab-(L-D)p I
Accordingly, the antibody may be conjugated to the drug either directly or via a linker. In Formula I, p is the average number of drug moieties per antibody, which can range, e.g., from about 1 to about 20 drug moieties per antibody, and in certain embodiments, from 1 to about 8 drug moieties per antibody. The invention includes a composition comprising a mixture of antibody-drug compounds of Formula I where the average drug loading per antibody is about 2 to about 5, or about 3 to about 4.
a. Exemplary Linkers
A linker may comprise one or more linker components. Exemplary linker components include 6-maleimidocaproyl (“MC”), maleimidopropanoyl (“MP”), valine-citrulline (“val-cit” or “vc”), alanine-phenylalanine (“ala-phe”), p-aminobenzyloxycarbonyl (a “PAB”), and those resulting from conjugation with linker reagents: N-Succinimidyl 4-(2-pyridylthio) pentanoate (“SPP”), N-succinimidyl 4-(N-maleimidomethyl)cyclohexane-1 carboxylate (“SMCC”), and N-Succinimidyl (4-iodo-acetyl)aminobenzoate (“SIAB”). Various linker components are known in the art, some of which are described below.
A linker may be a “cleavable linker,” facilitating release of a drug in the cell. For example, an acid-labile linker (e.g., hydrazone), protease-sensitive (e.g., peptidase-sensitive) linker, photolabile linker, -dimethyl linker or disulfide-containing linker (Chari et al., Cancer Research 52:127-131 (1992); U.S. Pat. No. 5,208,020) may be used.
In certain embodiments, a linker is as shown in the following Formula II:
-Aa-Ww—Yy— II
wherein A is a stretcher unit, and a is an integer from 0 to 1; W is an amino acid unit, and w is an integer from 0 to 12; Y is a spacer unit, and y is 0, 1, or 2; and Ab, D, and p are defined as above for Formula I. Exemplary embodiments of such linkers are described in US 2005-0238649 A1, which is expressly incorporated herein by reference.
In some embodiments, a linker component may comprise a “stretcher unit” that links an antibody to another linker component or to a drug moiety. Exemplary stretcher units are shown below (wherein the wavy line indicates sites of covalent attachment to an antibody):
In some embodiments, a linker component may comprise an amino acid unit. In one such embodiment, the amino acid unit allows for cleavage of the linker by a protease, thereby facilitating release of the drug from the immunoconjugate upon exposure to intracellular proteases, such as lysosomal enzymes. See, e.g., Doronina et al. (2003) Nat. Biotechnol. 21:778-784. Exemplary amino acid units include, but are not limited to, a dipeptide, a tripeptide, a tetrapeptide, and a pentapeptide. Exemplary dipeptides include: valine-citrulline (vc or val-cit), alanine-phenylalanine (af or ala-phe); phenylalanine-lysine (fk or phe-lys); or N-methyl-valine-citrulline (Me-val-cit). Exemplary tripeptides include: glycine-valine-citrulline (gly-val-cit) and glycine-glycine-glycine (gly-gly-gly). An amino acid unit may comprise amino acid residues that occur naturally, as well as minor amino acids and non-naturally occurring amino acid analogs, such as citrulline. Amino acid units can be designed and optimized in their selectivity for enzymatic cleavage by a particular enzyme, for example, a tumor-associated protease, cathepsin B, C and D, or a plasmin protease.
In some embodiments, a linker component may comprise a “spacer” unit that links the antibody to a drug moiety, either directly or by way of a stretcher unit and/or an amino acid unit. A spacer unit may be “self-immolative” or a “non-self-immolative.” A “non-self-immolative” spacer unit is one in which part or all of the spacer unit remains bound to the drug moiety upon enzymatic (e.g., proteolytic) cleavage of the ADC. Examples of non-self-immolative spacer units include, but are not limited to, a glycine spacer unit and a glycine-glycine spacer unit. Other combinations of peptidic spacers susceptible to sequence-specific enzymatic cleavage are also contemplated. For example, enzymatic cleavage of an ADC containing a glycine-glycine spacer unit by a tumor-cell associated protease would result in release of a glycine-glycine-drug moiety from the remainder of the ADC. In one such embodiment, the glycine-glycine-drug moiety is then subjected to a separate hydrolysis step in the tumor cell, thus cleaving the glycine-glycine spacer unit from the drug moiety.
A “self-immolative” spacer unit allows for release of the drug moiety without a separate hydrolysis step. In certain embodiments, a spacer unit of a linker comprises a p-aminobenzyl unit. In one such embodiment, a p-aminobenzyl alcohol is attached to an amino acid unit via an amide bond, and a carbamate, methylcarbamate, or carbonate is made between the benzyl alcohol and a cytotoxic agent. See, e.g., Hamann et al. (2005) Expert Opin. Ther. Patents (2005) 15:1087-1103. In one embodiment, the spacer unit is p-aminobenzyloxycarbonyl (PAB). In certain embodiments, the phenylene portion of a p-amino benzyl unit is substituted with Qm, wherein Q is —C1-C8 alkyl, —O—(C1-C8 alkyl), -halogen, -nitro or -cyano; and m is an integer ranging from 0-4. Examples of self-immolative spacer units further include, but are not limited to, aromatic compounds that are electronically similar to p-aminobenzyl alcohol (see, e.g., US 2005/0256030 A1), such as 2-aminoimidazol-5-methanol derivatives (Hay et al. (1999) Bioorg. Med. Chem. Lett. 9:2237) and ortho- or para-aminobenzylacetals. Spacers can be used that undergo cyclization upon amide bond hydrolysis, such as substituted and unsubstituted 4-aminobutyric acid amides (Rodrigues et al., Chemistry Biology, 1995, 2, 223); appropriately substituted bicyclo[2.2.1] and bicyclo[2.2.2] ring systems (Storm, et al., J. Amer. Chem. Soc., 1972, 94, 5815); and 2-aminophenylpropionic acid amides (Amsberry, et al., J. Org. Chem., 1990, 55, 5867). Elimination of amine-containing drugs that are substituted at the a-position of glycine (Kingsbury, et al., J. Med. Chem., 1984, 27, 1447) are also examples of self-immolative spacers useful in ADCs.
In one embodiment, a spacer unit is a branched bis(hydroxymethyl)styrene (BHMS) unit as depicted below, which can be used to incorporate and release multiple drugs.
wherein Q is —C1-C8 alkyl, —O—(C1-C8 alkyl), -halogen, -nitro or -cyano; m is an integer ranging from 0-4; n is 0 or 1; and p ranges raging from 1 to about 20.
In another embodiment, linker L may be a dendritic type linker for covalent attachment of more than one drug moiety through a branching, multifunctional linker moiety to an antibody (Sun et al (2002) Bioorganic & Medicinal Chemistry Letters 12:2213-2215; Sun et al (2003) Bioorganic & Medicinal Chemistry 11:1761-1768). Dendritic linkers can increase the molar ratio of drug to antibody, i.e. loading, which is related to the potency of the ADC. Thus, where a cysteine engineered antibody bears only one reactive cysteine thiol group, a multitude of drug moieties may be attached through a dendritic linker.
Exemplary linker components and combinations thereof are shown below in the context of ADCs of Formula II:
Linkers components, including stretcher, spacer, and amino acid units, may be synthesized by methods known in the art, such as those described in US 2005-0238649 A1.
b. Exemplary Drug Moieties
(1) Maytansine and Maytansinoids
In some embodiments, an immunoconjugate comprises an antibody conjugated to one or more maytansinoid molecules. Maytansinoids are mitototic inhibitors which act by inhibiting tubulin polymerization. Maytansine was first isolated from the east African shrub Maytenus serrata (U.S. Pat. No. 3,896,111). Subsequently, it was discovered that certain microbes also produce maytansinoids, such as maytansinol and C-3 maytansinol esters (U.S. Pat. No. 4,151,042). Synthetic maytansinol and derivatives and analogues thereof are disclosed, for example, in U.S. Pat. Nos. 4,137,230; 4,248,870; 4,256,746; 4,260,608; 4,265,814; 4,294,757; 4,307,016; 4,308,268; 4,308,269; 4,309,428; 4,313,946; 4,315,929; 4,317,821; 4,322,348; 4,331,598; 4,361,650; 4,364,866; 4,424,219; 4,450,254; 4,362,663; and 4,371,533.
Maytansinoid drug moieties are attractive drug moieties in antibody-drug conjugates because they are: (i) relatively accessible to prepare by fermentation or chemical modification or derivatization of fermentation products, (ii) amenable to derivatization with functional groups suitable for conjugation through non-disulfide linkers to antibodies, (iii) stable in plasma, and (iv) effective against a variety of tumor cell lines.
Maytansine compounds suitable for use as maytansinoid drug moieties are well known in the art and can be isolated from natural sources according to known methods or produced using genetic engineering techniques (see Yu et al (2002) PNAS 99:7968-7973). Maytansinol and maytansinol analogues may also be prepared synthetically according to known methods.
Exemplary maytansinoid drug moieties include those having a modified aromatic ring, such as: C-19-dechloro (U.S. Pat. No. 4,256,746) (prepared by lithium aluminum hydride reduction of ansamytocin P2); C-20-hydroxy (or C-20-demethyl) +/−C-19-dechloro (U.S. Pat. Nos. 4,361,650 and 4,307,016) (prepared by demethylation using Streptomyces or Actinomyces or dechlorination using LAH); and C-20-demethoxy, C-20-acyloxy (—OCOR), +/−dechloro (U.S. Pat. No. 4,294,757) (prepared by acylation using acyl chlorides). and those having modifications at other positions.
Exemplary maytansinoid drug moieties also include those having modifications such as: C-9-SH (U.S. Pat. No. 4,424,219) (prepared by the reaction of maytansinol with H2S or P2S5); C-14-alkoxymethyl(demethoxy/CH2 OR) (U.S. Pat. No. 4,331,598); C-14-hydroxymethyl or acyloxymethyl (CH2OH or CH2OAc) (U.S. Pat. No. 4,450,254) (prepared from Nocardia); C-15-hydroxy/acyloxy (U.S. Pat. No. 4,364,866) (prepared by the conversion of maytansinol by Streptomyces); C-15-methoxy (U.S. Pat. Nos. 4,313,946 and 4,315,929) (isolated from Trewia nudlflora); C-18-N-demethyl (U.S. Pat. Nos. 4,362,663 and 4,322,348) (prepared by the demethylation of maytansinol by Streptomyces); and 4,5-deoxy (U.S. Pat. No. 4,371,533) (prepared by the titanium trichloride/LAH reduction of maytansinol).
Many positions on maytansine compounds are known to be useful as the linkage position, depending upon the type of link. For example, for forming an ester linkage, the C-3 position having a hydroxyl group, the C-14 position modified with hydroxymethyl, the C-15 position modified with a hydroxyl group and the C-20 position having a hydroxyl group are all suitable.
Maytansinoid drug moieties include those having the structure:
where the wavy line indicates the covalent attachment of the sulfur atom of the maytansinoid drug moiety to a linker of an ADC. R may independently be H or a C1-C6 alkyl. The alkylene chain attaching the amide group to the sulfur atom may be methanyl, ethanyl, or propyl, i.e., m is 1, 2, or 3 (U.S. Pat. No. 6,334,10; U.S. Pat. No. 5,208,020; Chari et al (1992) Cancer Res. 52:127-131; Liu et al (1996) Proc. Natl. Acad. Sci. USA 93:8618-8623).
All stereoisomers of the maytansinoid drug moiety are contemplated for the compounds of the invention, i.e. any combination of R and S configurations at the chiral carbons of D. In one embodiment, the maytansinoid drug moiety will have the following stereochemistry:
Exemplary embodiments of maytansinoid drug moieities include: DM1; DM3; and DM4, having the structures:
wherein the wavy line indicates the covalent attachment of the sulfur atom of the drug to a linker (L) of an antibody-drug conjugate. (WO 2005/037992; US 2005/0276812 A1).
Other exemplary maytansinoid antibody-drug conjugates have the following structures and abbreviations, (wherein Ab is antibody and p is 1 to about 8):
Exemplary antibody-drug conjugates where DM1 is linked through a BMPEO linker to a thiol group of the antibody have the structure and abbreviation:
where Ab is antibody; n is 0, 1, or 2; and p is 1, 2, 3, or 4.
Maytansinoids, such as DM1, are mitototic inhibitors which act by inhibiting tubulin polymerization. Maytansine was first isolated from the east African shrub Maytenus serrata (U.S. Pat. No. 3,896,111). Subsequently, it was discovered that certain microbes also produce maytansinoids, such as maytansinol and C-3 maytansinol esters (U.S. Pat. No. 4,151,042). Synthetic maytansinol and derivatives and analogues thereof are disclosed, for example, in U.S. Pat. Nos. 4,137,230; 4,248,870; 4,256,746; 4,260,608; 4,265,814; 4,294,757; 4,307,016; 4,308,268; 4,308,269; 4,309,428; 4,313,946; 4,315,929; 4,317,821; 4,322,348; 4,331,598; 4,361,650; 4,364,866; 4,424,219; 4,450,254; 4,362,663; and 4,371,533, the disclosures of which are hereby expressly incorporated by reference.
In an attempt to improve their therapeutic index, maytansine and maytansinoids have been conjugated to antibodies specifically binding to tumor cell antigens. Immunoconjugates containing maytansinoids and their therapeutic use are disclosed, for example, in U.S. Pat. Nos. 5,208,020, 5,416,064 and European Patent EP 0 425 235 B1, the disclosures of which are hereby expressly incorporated by reference.
Anti-TAHO antibody-maytansinoid conjugates are prepared by chemically linking an anti-TAHO antibody to a maytansinoid molecule without significantly diminishing the biological activity of either the antibody or the maytansinoid molecule. See, e.g., U.S. Pat. No. 5,208,020 (the disclosure of which is hereby expressly incorporated by reference). Maytansinoids can be synthesized by known techniques or isolated from natural sources. Suitable maytansinoids are disclosed, for example, in U.S. Pat. No. 5,208,020 and in the other patents and nonpatent publications referred to hereinabove, such as maytansinoids are maytansinol and maytansinol analogues modified in the aromatic ring or at other positions of the maytansinol molecule, such as various, maytansinol esters.
There are many linking groups known in the art for making antibody-maytansinoid conjugates, including, for example, those disclosed in U.S. Pat. No. 5,208,020 or EP Patent 0 425 235 B1, and Chari et al., Cancer Research 52:127-131 (1992) and US 2005/016993 A1, the disclosures of which are expressly incorporated by reference. Antibody-maytansinoid conjugates comprising the linker component SMCC may be prepared as disclosed in US 2005/0276812 A1, “Antibody-drug conjugates and Methods.” The linking groups include disulfide groups, thioether groups, acid labile groups, photolabile groups, peptidase labile groups, or esterase labile groups, as disclosed in the above-identified patents. Additional linkers are described and exemplified herein.
Conjugates of the antibody and maytansinoid may be made using a variety of bifunctional protein coupling agents such as N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP), succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate, iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCL), active esters (such as disuccinimidyl suberate), aldehydes (such as glutareldehyde), bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as toluene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene). Particularly preferred coupling agents include N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP) (Carlsson et al., Biochem. J. 173:723-737 [1978]), sulfosuccinimidyl maleimidomethyl cyclohexane carboxylate (SMCC) and N-succinimidyl-4-(2-pyridylthio)pentanoate (SPP) to provide for a disulfide linkage. Other useful linkers include cys-MC-vc-PAB (a valine-citrulline (vc) dipeptide linker reagent having a maleimide component and a para-aminobenzylcarbamoyl (PAB) self-immolative component.
The linker may be attached to the maytansinoid molecule at various positions, depending on the type of the link. For example, an ester linkage may be formed by reaction with a hydroxyl group using conventional coupling techniques. The reaction may occur at the C-3 position having a hydroxyl group, the C-14 position modified with hyrdoxymethyl, the C-15 position modified with a hydroxyl group, and the C-20 position having a hydroxyl group. In a preferred embodiment, the linkage is formed at the C-3 position of maytansinol or a maytansinol analogue.
(2) Auristatins and Dolastatins
In some embodiments, an immunoconjugate comprises an antibody conjugated to dolastatin or a dolastatin peptidic analog or derivative, e.g., an auristatin (U.S. Pat. Nos. 5,635,483; 5,780,588). Dolastatins and auristatins have been shown to interfere with microtubule dynamics, GTP hydrolysis, and nuclear and cellular division (Woyke et al (2001) Antimicrob. Agents and Chemother. 45(12):3580-3584) and have anticancer (U.S. Pat. No. 5,663,149) and antifungal activity (Pettit et al (1998) Antimicrob. Agents Chemother. 42:2961-2965). The dolastatin or auristatin drug moiety may be attached to the antibody through the N (amino) terminus or the C (carboxyl) terminus of the peptidic drug moiety (WO 02/088172).
Exemplary auristatin embodiments include the N-terminus linked monomethylauristatin drug moieties DE and DF, disclosed in Senter et al, Proceedings of the American Association for Cancer Research, Volume 45, Abstract Number 623, presented Mar. 28, 2004, (US 2005/0238649, the disclosure of which is expressly incorporated by reference in its entirety).
A peptidic drug moiety may be selected from Formulas DE and DF below:
wherein the wavy line of DE and DF indicates the covalent attachment site to an antibody or antibody-linker component, and independently at each location:
R2 is selected from H and C1-C8 alkyl;
R3 is selected from H, C1-C8 alkyl, C3-C8 carbocycle, aryl, C1-C8 alkyl-aryl, C1-C8 alkyl-(C3-C8 carbocycle), C3-C8 heterocycle and C1-C8 alkyl-(C3-C8 heterocycle);
R4 is selected from H, C1-C8 alkyl, C3-C8 carbocycle, aryl, C1-C8 alkyl-aryl, C1-C8 alkyl-(C3-C8 carbocycle), C3-C8 heterocycle and C1-C8 alkyl-(C3-C8 heterocycle);
R5 is selected from H and methyl;
or R4 and R5 jointly form a carbocyclic ring and have the formula —(CRaRb)n— wherein Ra and Rb are independently selected from H, C1-C8 alkyl and C3-C8 carbocycle and n is selected from 2, 3, 4, 5 and 6;
R6 is selected from H and C1-C8 alkyl;
R7 is selected from H, C1-C8 alkyl, C3-C8 carbocycle, aryl, C1-C8 alkyl-aryl, C1-C8 alkyl-(C3-C8 carbocycle), C3-C8 heterocycle and C1-C8 alkyl-(C3-C8 heterocycle);
each R8 is independently selected from H, OH, C1-C8 alkyl, C3-C8 carbocycle and O—(C1-C8 alkyl);
R9 is selected from H and C1-C8 alkyl;
R10 is selected from aryl or C3-C8 heterocycle;
Z is O, S, NH, or NR12, wherein R12 is C1-C8 alkyl;
R11 is selected from H, C1-C20 alkyl, aryl, C3-C8 heterocycle, —(R13O)m—R14, or —(R13O)m—CH(R15)2;
m is an integer ranging from 1-1000;
R13 is C2-C8 alkyl;
R14 is H or C1-C8 alkyl;
each occurrence of R15 is independently H, COOH, —(CH2)n—N(R16)2, —(CH2)n—SO3H, or —(CH2)n—SO3-C1-C8 alkyl;
each occurrence of R16 is independently H, C1-C8 alkyl, or —(CH2)n—COOH;
R18 is selected from —C(R8)2—C(R8)2-aryl, —C(R8)2—C(R8)2—(C3-C8 heterocycle), and —C(R8)2—C(R8)2—(C3-C8 carbocycle); and
n is an integer ranging from 0 to 6.
In one embodiment, R3, R4 and R7 are independently isopropyl or sec-butyl and R5 is —H or methyl. In an exemplary embodiment, R3 and R4 are each isopropyl, R5 is —H, and R7 is sec-butyl.
In yet another embodiment, R2 and R6 are each methyl, and R9 is —H.
In still another embodiment, each occurrence of R8 is —OCH3.
In an exemplary embodiment, R3 and R4 are each isopropyl, R2 and R6 are each methyl, R5 is —H, R7 is sec-butyl, each occurrence of R8 is —OCH3, and R9 is —H.
In one embodiment, Z is —O— or —NH—.
In one embodiment, R10 is aryl.
In an exemplary embodiment, R10 is -phenyl.
In an exemplary embodiment, when Z is —O—, R11 is —H, methyl or t-butyl.
In one embodiment, when Z is —NH, R11 is —CH(R15)2, wherein R15 is —(CH2)n—N(R16)2, and R16 is —C1-C8 alkyl or —(CH2)n—COOH.
In another embodiment, when Z is —NH, R11 is —CH(R15)2, wherein R15 is —(CH2)n—SO3H.
An exemplary auristatin embodiment of formula DE is MMAE, wherein the wavy line indicates the covalent attachment to a linker (L) of an antibody-drug conjugate:
An exemplary auristatin embodiment of formula DF is MMAF, wherein the wavy line indicates the covalent attachment to a linker (L) of an antibody-drug conjugate (see US 2005/0238649 and Doronina et al. (2006) Bioconjugate Chem. 17:114-124):
Other exemplary embodiments include monomethylvaline compounds having phenylalanine carboxy modifications at the C-terminus of the pentapeptide auristatin drug moiety (WO 2007/008848) and monomethylvaline compounds having phenylalanine sidechain modifications at the C-terminus of the pentapeptide auristatin drug moiety (WO 2007/008603).
Other drug moieties include the following MMAF derivatives, wherein the wavy line indicates the covalent attachment to a linker (L) of an antibody-drug conjugate:
In one aspect, hydrophilic groups including but not limited to, triethylene glycol esters (TEG), as shown above, can be attached to the drug moiety at R11. Without being bound by any particular theory, the hydrophilic groups assist in the internalization and non-agglomeration of the drug moiety.
Exemplary embodiments of ADCs of Formula I comprising an auristatin/dolastatin or derivative thereof are described in US 2005-0238649 and Doronina et al. (2006) Bioconjugate Chem. 17:114-124, which is expressly incorporated herein by reference. Exemplary embodiments of ADCs of Formula I comprising MMAE or MMAF and various linker components have the following structures and abbreviations (wherein “Ab” is an antibody; p is 1 to about 8, “Val-Cit” or “vc” is a valine-citrulline dipeptide; and “S” is a sulfur atom:
Exemplary embodiments of ADCs of Formula I comprising MMAF and various linker components further include Ab-MC-PAB-MMAF and Ab-PAB-MMAF. Interestingly, immunoconjugates comprising MMAF attached to an antibody by a linker that is not proteolytically cleavable have been shown to possess activity comparable to immunoconjugates comprising MMAF attached to an antibody by a proteolytically cleavable linker. See, Doronina et al. (2006) Bioconjugate Chem. 17:114-124. In such instances, drug release is believed to be effected by antibody degradation in the cell. Id.
Typically, peptide-based drug moieties can be prepared by forming a peptide bond between two or more amino acids and/or peptide fragments. Such peptide bonds can be prepared, for example, according to the liquid phase synthesis method (see E. Schröder and K. Lübke, “The Peptides”, volume 1, pp 76-136, 1965, Academic Press) that is well known in the field of peptide chemistry. Auristatin/dolastatin drug moieties may be prepared according to the methods of: US 2005-0238649 A1; U.S. Pat. No. 5,635,483; U.S. Pat. No. 5,780,588; Pettit et al (1989) J. Am. Chem. Soc. 111:5463-5465; Pettit et al (1998) Anti-Cancer Drug Design 13:243-277; Pettit, G. R., et al. Synthesis, 1996, 719-725; Pettit et al (1996) J. Chem. Soc. Perkin Trans. 1 5:859-863; and Doronina (2003) Nat. Biotechnol. 21(7):778-784.
In particular, auristatin/dolastatin drug moieties of formula DF, such as MMAF and derivatives thereof, may be prepared using methods described in US 2005-0238649 A1 and Doronina et al. (2006) Bioconjugate Chem. 17:114-124. Auristatin/dolastatin drug moieties of formula DE, such as MMAE and derivatives thereof, may be prepared using methods described in Doronina et al. (2003) Nat. Biotech. 21:778-784. Drug-linker moieties MC-MMAF, MC-MMAE, MC-vc-PAB-MMAF, and MC-vc-PAB-MMAE may be conveniently synthesized by routine methods, e.g., as described in Doronina et al. (2003) Nat. Biotech. 21:778-784, and Patent Application Publication No. US 2005/0238649 A1, and then conjugated to an antibody of interest.
(3) Calicheamicin
In other embodiments, the immunoconjugate comprises an antibody conjugated to one or more calicheamicin molecules. The calicheamicin family of antibiotics are capable of producing double-stranded DNA breaks at sub-picomolar concentrations. For the preparation of conjugates of the calicheamicin family, see U.S. Pat. Nos. 5,712,374, 5,714,586, 5,739,116, 5,767,285, 5,770,701, 5,770,710, 5,773,001, 5,877,296 (all to American Cyanamid Company). Structural analogues of calicheamicin which may be used include, but are not limited to, γ1I, α2I, α3I, N-acetyl-γ1I, PSAG and θ1I (Hinman et al., Cancer Research 53:3336-3342 (1993), Lode et al., Cancer Research 58:2925-2928 (1998), and the aforementioned U.S. patents to American Cyanamid). Another anti-tumor drug to which the antibody can be conjugated is QFA, which is an antifolate. Both calicheamicin and QFA have intracellular sites of action and do not readily cross the plasma membrane. Therefore, cellular uptake of these agents through antibody-mediated internalization greatly enhances their cytotoxic effects.
c. Other Cytotoxic Agents
Other antitumor agents that can be conjugated to the anti-TAHO antibodies of the invention include BCNU, streptozoicin, vincristine and 5-fluorouracil, the family of agents known collectively LL-E33288 complex described in U.S. Pat. Nos. 5,053,394, 5,770,710, as well as esperamicins (U.S. Pat. No. 5,877,296).
Enzymatically active toxins and fragments thereof which can be used include diphtheria A chain, nonbinding active fragments of diphtheria toxin, exotoxin A chain (from Pseudomonas aeruginosa), ricin A chain, abrin A chain, modeccin A chain, alpha-sarcin, Aleurites fordii proteins, dianthin proteins, Phytolaca americana proteins (PAPI, PAPII, and PAP-S), momordica charantia inhibitor, curcin, crotin, sapaonaria officinalis inhibitor, gelonin, mitogellin, restrictocin, phenomycin, enomycin and the tricothecenes. See, for example, WO 93/21232 published Oct. 28, 1993.
The present invention further contemplates an immunoconjugate formed between an antibody and a compound with nucleolytic activity (e.g., a ribonuclease or a DNA endonuclease such as a deoxyribonuclease; DNase).
For selective destruction of the tumor, the antibody may comprise a highly radioactive atom. A variety of radioactive isotopes are available for the production of radioconjugated anti-TAHO antibodies. Examples include At211, I131, I125, Y90, Re186, Re188, Sm153, Bi212, P32, Pb212 and radioactive isotopes of Lu. When the conjugate is used for detection, it may comprise a radioactive atom for scintigraphic studies, for example tc99m or I123, or a spin label for nuclear magnetic resonance (NMR) imaging (also known as magnetic resonance imaging, mri), such as iodine-123 again, iodine-131, indium-111, fluorine-19, carbon-13, nitrogen-15, oxygen-17, gadolinium, manganese or iron.
The radio- or other labels may be incorporated in the conjugate in known ways. For example, the peptide may be biosynthesized or may be synthesized by chemical amino acid synthesis using suitable amino acid precursors involving, for example, fluorine-19 in place of hydrogen. Labels such as tc99m or I123, Re186, Re188 and In111 can be attached via a cysteine residue in the peptide. Yttrium-90 can be attached via a lysine residue. The IODOGEN method (Fraker et al (1978) Biochem. Biophys. Res. Commun. 80: 49-57 can be used to incorporate iodine-123. “Monoclonal Antibodies in Immunoscintigraphy” (Chatal, CRC Press 1989) describes other methods in detail.
In certain embodiments, an immunoconjugate may comprise an antibody conjugated to a prodrug-activating enzyme that converts a prodrug (e.g., a peptidyl chemotherapeutic agent, see WO 81/01145) to an active drug, such as an anti-cancer drug. Such immunoconjugates are useful in antibody-dependent enzyme-mediated prodrug therapy (“ADEPT”). Enzymes that may be conjugated to an antibody include, but are not limited to, alkaline phosphatases, which are useful for converting phosphate-containing prodrugs into free drugs; arylsulfatases, which are useful for converting sulfate-containing prodrugs into free drugs; cytosine deaminase, which is useful for converting non-toxic 5-fluorocytosine into the anti-cancer drug, 5-fluorouracil; proteases, such as serratia protease, thermolysin, subtilisin, carboxypeptidases and cathepsins (such as cathepsins B and L), which are useful for converting peptide-containing prodrugs into free drugs; D-alanylcarboxypeptidases, which are useful for converting prodrugs that contain D-amino acid substituents; carbohydrate-cleaving enzymes such as β-galactosidase and neuraminidase, which are useful for converting glycosylated prodrugs into free drugs; β-lactamase, which is useful for converting drugs derivatized with β-lactams into free drugs; and penicillin amidases, such as penicillin V amidase and penicillin G amidase, which are useful for converting drugs derivatized at their amine nitrogens with phenoxyacetyl or phenylacetyl groups, respectively, into free drugs. Enzymes may be covalently bound to antibodies by recombinant DNA techniques well known in the art. See, e.g., Neuberger et al., Nature 312:604-608 (1984).
d. Drug Loading
Drug loading is represented by p, the average number of drug moieties per antibody in a molecule of Formula I. Drug loading may range from 1 to 20 drug moieties (D) per antibody. ADCs of Formula I include collections of antibodies conjugated with a range of drug moieties, from 1 to 20. The average number of drug moieties per antibody in preparations of ADC from conjugation reactions may be characterized by conventional means such as mass spectroscopy, ELISA assay, and HPLC. The quantitative distribution of ADC in terms of p may also be determined. In some instances, separation, purification, and characterization of homogeneous ADC where p is a certain value from ADC with other drug loadings may be achieved by means such as reverse phase HPLC or electrophoresis. Pharmaceutical formulations of Formula I antibody-drug conjugates may thus be a heterogeneous mixture of such conjugates with antibodies linked to 1, 2, 3, 4, or more drug moieties.
For some antibody-drug conjugates, p may be limited by the number of attachment sites on the antibody. For example, where the attachment is a cysteine thiol, as in the exemplary embodiments above, an antibody may have only one or several cysteine thiol groups, or may have only one or several sufficiently reactive thiol groups through which a linker may be attached. In certain embodiments, higher drug loading, e.g. p>5, may cause aggregation, insolubility, toxicity, or loss of cellular permeability of certain antibody-drug conjugates. In certain embodiments, the drug loading for an ADC of the invention ranges from 1 to about 8; from about 2 to about 6; or from about 3 to about 5. Indeed, it has been shown that for certain ADCs, the optimal ratio of drug moieties per antibody may be less than 8, and may be about 2 to about 5. See US 2005-0238649 A1.
In certain embodiments, fewer than the theoretical maximum of drug moieties are conjugated to an antibody during a conjugation reaction. An antibody may contain, for example, lysine residues that do not react with the drug-linker intermediate or linker reagent, as discussed below. Generally, antibodies do not contain many free and reactive cysteine thiol groups which may be linked to a drug moiety; indeed most cysteine thiol residues in antibodies exist as disulfide bridges. In certain embodiments, an antibody may be reduced with a reducing agent such as dithiothreitol (DTT) or tricarbonylethylphosphine (TCEP), under partial or total reducing conditions, to generate reactive cysteine thiol groups. In certain embodiments, an antibody is subjected to denaturing conditions to reveal reactive nucleophilic groups such as lysine or cysteine.
The loading (drug/antibody ratio) of an ADC may be controlled in different ways, e.g., by: (i) limiting the molar excess of drug-linker intermediate or linker reagent relative to antibody, (ii) limiting the conjugation reaction time or temperature, and (iii) partial or limiting reductive conditions for cysteine thiol modification.
It is to be understood that where more than one nucleophilic group reacts with a drug-linker intermediate or linker reagent followed by drug moiety reagent, then the resulting product is a mixture of ADC compounds with a distribution of one or more drug moieties attached to an antibody. The average number of drugs per antibody may be calculated from the mixture by a dual ELISA antibody assay, which is specific for antibody and specific for the drug. Individual ADC molecules may be identified in the mixture by mass spectroscopy and separated by HPLC, e.g. hydrophobic interaction chromatography (see, e.g., McDonagh et al (2006) Prot. Engr. Design & Selection 19(7):299-307; Hamblett et al (2004) Clin. Cancer Res. 10:7063-7070; Hamblett, K. J., et al. “Effect of drug loading on the pharmacology, pharmacokinetics, and toxicity of an anti-CD30 antibody-drug conjugate,” Abstract No. 624, American Association for Cancer Research, 2004 Annual Meeting, Mar. 27-31, 2004, Proceedings of the AACR, Volume 45, March 2004; Alley, S. C., et al. “Controlling the location of drug attachment in antibody-drug conjugates,” Abstract No. 627, American Association for Cancer Research, 2004 Annual Meeting, Mar. 27-31, 2004, Proceedings of the AACR, Volume 45, March 2004). In certain embodiments, a homogeneous ADC with a single loading value may be isolated from the conjugation mixture by electrophoresis or chromatography.
e. Certain Methods of Preparing Immunconjugates
An ADC of Formula I may be prepared by several routes employing organic chemistry reactions, conditions, and reagents known to those skilled in the art, including: (1) reaction of a nucleophilic group of an antibody with a bivalent linker reagent to form Ab-L via a covalent bond, followed by reaction with a drug moiety D; and (2) reaction of a nucleophilic group of a drug moiety with a bivalent linker reagent, to form D-L, via a covalent bond, followed by reaction with a nucleophilic group of an antibody. Exemplary methods for preparing an ADC of Formula I via the latter route are described in US 2005-0238649 A1, which is expressly incorporated herein by reference.
Nucleophilic groups on antibodies include, but are not limited to: (i) N-terminal amine groups, (ii) side chain amine groups, e.g. lysine, (iii) side chain thiol groups, e.g. cysteine, and (iv) sugar hydroxyl or amino groups where the antibody is glycosylated. Amine, thiol, and hydroxyl groups are nucleophilic and capable of reacting to form covalent bonds with electrophilic groups on linker moieties and linker reagents including: (i) active esters such as NHS esters, HOBt esters, haloformates, and acid halides; (ii) alkyl and benzyl halides such as haloacetamides; (iii) aldehydes, ketones, carboxyl, and maleimide groups. Certain antibodies have reducible interchain disulfides, i.e. cysteine bridges. Antibodies may be made reactive for conjugation with linker reagents by treatment with a reducing agent such as DTT (dithiothreitol) or tricarbonylethylphosphine (TCEP), such that the antibody is fully or partially reduced. Each cysteine bridge will thus form, theoretically, two reactive thiol nucleophiles. Additional nucleophilic groups can be introduced into antibodies through modification of lysine residues, e.g., by reacting lysine residues with 2-iminothiolane (Traut's reagent), resulting in conversion of an amine into a thiol. Reactive thiol groups may be introduced into an antibody by introducing one, two, three, four, or more cysteine residues (e.g., by preparing variant antibodies comprising one or more non-native cysteine amino acid residues).
Antibody-drug conjugates of the invention may also be produced by reaction between an electrophilic group on an antibody, such as an aldehyde or ketone carbonyl group, with a nucleophilic group on a linker reagent or drug. Useful nucleophilic groups on a linker reagent include, but are not limited to, hydrazide, oxime, amino, hydrazine, thiosemicarbazone, hydrazine carboxylate, and arylhydrazide. In one embodiment, an antibody is modified to introduce electrophilic moieties that are capable of reacting with nucleophilic substituents on the linker reagent or drug. In another embodiment, the sugars of glycosylated antibodies may be oxidized, e.g. with periodate oxidizing reagents, to form aldehyde or ketone groups which may react with the amine group of linker reagents or drug moieties. The resulting imine Schiff base groups may form a stable linkage, or may be reduced, e.g. by borohydride reagents to form stable amine linkages. In one embodiment, reaction of the carbohydrate portion of a glycosylated antibody with either galactose oxidase or sodium meta-periodate may yield carbonyl (aldehyde and ketone) groups in the antibody that can react with appropriate groups on the drug (Hermanson, Bioconjugate Techniques). In another embodiment, antibodies containing N-terminal serine or threonine residues can react with sodium meta-periodate, resulting in production of an aldehyde in place of the first amino acid (Geoghegan & Stroh, (1992) Bioconjugate Chem. 3:138-146; U.S. Pat. No. 5,362,852). Such an aldehyde can be reacted with a drug moiety or linker nucleophile.
Nucleophilic groups on a drug moiety include, but are not limited to: amine, thiol, hydroxyl, hydrazide, oxime, hydrazine, thiosemicarbazone, hydrazine carboxylate, and arylhydrazide groups capable of reacting to form covalent bonds with electrophilic groups on linker moieties and linker reagents including: (i) active esters such as NHS esters, HOBt esters, haloformates, and acid halides; (ii) alkyl and benzyl halides such as haloacetamides; (iii) aldehydes, ketones, carboxyl, and maleimide groups.
The compounds of the invention expressly contemplate, but are not limited to, ADC prepared with the following cross-linker reagents: BMPS, EMCS, GMBS, HBVS, LC-SMCC, MBS, MPBH, SBAP, SIA, SIAB, SMCC, SMPB, SMPH, sulfo-EMCS, sulfo-GMBS, sulfo-KMUS, sulfo-MBS, sulfo-SIAB, sulfo-SMCC, and sulfo-SMPB, and SVSB (succinimidyl-(4-vinylsulfone)benzoate) which are commercially available (e.g., from Pierce Biotechnology, Inc., Rockford, Ill., U.S.A; see pages 467-498, 2003-2004 Applications Handbook and Catalog.
Conjugates of the antibody and cytotoxic agent may be made using a variety of bifunctional protein coupling agents such as N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP), succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate, iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCL), active esters (such as disuccinimidyl suberate), aldehydes (such as glutareldehyde), bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as tolyene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene). For example, a ricin immunotoxin can be prepared as described in Vitetta et al., Science 238:1098 (1987). Carbon-14-labeled 1-isothiocyanatobenzyl-3-methyldiethylene triaminepentaacetic acid (MX-DTPA) is an exemplary chelating agent for conjugation of radionucleotide to the antibody. See WO94/11026. The linker may be a “cleavable linker” facilitating release of the cytotoxic drug in the cell. For example, an acid-labile linker, peptidase-sensitive linker, photolabile linker, dimethyl linker or disulfide-containing linker (Chari et al., Cancer Research 52:127-131 (1992); U.S. Pat. No. 5,208,020) may be used.
Alternatively, a fusion protein comprising the anti-TAHO antibody and cytotoxic agent may be made, e.g., by recombinant techniques or peptide synthesis. The length of DNA may comprise respective regions encoding the two portions of the conjugate either adjacent one another or separated by a region encoding a linker peptide which does not destroy the desired properties of the conjugate.
In yet another embodiment, the antibody may be conjugated to a “receptor” (such streptavidin) for utilization in tumor pre-targeting wherein the antibody-receptor conjugate is administered to the patient, followed by removal of unbound conjugate from the circulation using a clearing agent and then administration of a “ligand” (e.g., avidin) which is conjugated to a cytotoxic agent (e.g., a radionucleotide).
a. Preparation of Cysteine Engineered Anti-TAHO Antibodies
DNA encoding an amino acid sequence variant of the cysteine engineered anti-TAHO antibodies, such as anti-human CD79b (TAHO5) and anti-cyno CD79b (TAHO40), and parent anti-TAHO antibodies of the invention, such as anti-human CD79b (TAHO5) and anti-cyno CD79b (TAHO40), is prepared by a variety of methods which include, but are not limited to, isolation from a natural source (in the case of naturally occurring amino acid sequence variants), preparation by site-directed (or oligonucleotide-mediated) mutagenesis (Carter (1985) et al Nucleic Acids Res. 13:4431-4443; Ho et al (1989) Gene (Amst.) 77:51-59; Kunkel et al (1987) Proc. Natl. Acad. Sci. USA 82:488; Liu et al (1998) J. Biol. Chem. 273:20252-20260), PCR mutagenesis (Higuchi, (1990) in PCR Protocols, pp. 177-183, Academic Press; Ito et al (1991) Gene 102:67-70; Bernhard et al (1994) Bioconjugate Chem. 5:126-132; and Vallette et al (1989) Nuc. Acids Res. 17:723-733), and cassette mutagenesis (Wells et al (1985) Gene 34:315-323) of an earlier prepared DNA encoding the polypeptide. Mutagenesis protocols, kits, and reagents are commercially available, e.g. QuikChange® Multi Site-Direct Mutagenesis Kit (Stratagene, La Jolla, Calif.). Single mutations are also generated by oligonucleotide directed mutagenesis using double stranded plasmid DNA as template by PCR based mutagenesis (Sambrook and Russel, (2001) Molecular Cloning: A Laboratory Manual, 3rd edition; Zoller et al (1983) Methods Enzymol. 100:468-500; Zoller, M. J. and Smith, M. (1982) Nucl. Acids Res. 10:6487-6500). Variants of recombinant antibodies may be constructed also by restriction fragment manipulation or by overlap extension PCR with synthetic oligonucleotides. Mutagenic primers encode the cysteine codon replacement(s). Standard mutagenesis techniques can be employed to generate DNA encoding such mutant cysteine engineered antibodies (Sambrook et al Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989; and Ausubel et al Current Protocols in Molecular Biology, Greene Publishing and Wiley-Interscience, New York, N.Y., 1993).
Phage display technology (McCafferty et al (1990) Nature 348:552-553) can be used to produce anti-TAHO human antibodies and antibody fragments in vitro, from immunoglobulin variable (V) domain gene repertoires from unimmunized donors. According to this technique, antibody V domain genes are cloned in-frame into either a major or minor coat protein gene of a filamentous bacteriophage, such as M13 or fd, and displayed as functional antibody fragments on the surface of the phage particle. Because the filamentous particle contains a single-stranded DNA copy of the phage genome, selections based on the functional properties of the antibody also result in selection of the gene encoding the antibody exhibiting those properties. Thus, the phage mimics some of the properties of the B-cell (Johnson et al (1993) Current Opinion in Structural Biology 3:564-571; Clackson et al (1991) Nature, 352:624-628; Marks et al (1991) J. Mol. Biol. 222:581-597; Griffith et al (1993) EMBO J. 12:725-734; U.S. Pat. No. 5,565,332; U.S. Pat. No. 5,573,905; U.S. Pat. No. 5,567,610; U.S. Pat. No. 5,229,275).
Anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), may be chemically synthesized using known oligopeptide synthesis methodology or may be prepared and purified using recombinant technology. The appropriate amino acid sequence, or portions thereof, may be produced by direct peptide synthesis using solid-phase techniques (Stewart et al., Solid-Phase Peptide Synthesis, (1969) W.H. Freeman Co., San Francisco, Calif.; Merrifield, (1963) J. Am. Chem. Soc., 85:2149-2154). In vitro protein synthesis may be performed using manual techniques or by automation. Automated solid phase synthesis may be accomplished, for instance, employing t-BOC or Fmoc protected amino acids and using an Applied Biosystems Peptide Synthesizer (Foster City, Calif.) using manufacturer's instructions. Various portions of the anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), or TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), may be chemically synthesized separately and combined using chemical or enzymatic methods to produce the desired anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), or TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40).
Various techniques have been developed for the production of antibody fragments. Traditionally, these fragments were derived via proteolytic digestion of intact antibodies (Morimoto et al (1992) Journal of Biochemical and Biophysical Methods 24:107-117; and Brennan et al (1985) Science, 229:81), or produced directly by recombinant host cells. Fab, Fv and ScFv anti-TAHO antibody fragments can all be expressed in and secreted from E. coli, thus allowing the facile production of large amounts of these fragments. Antibody fragments can be isolated from the antibody phage libraries discussed herein. Alternatively, Fab′-SH fragments can be directly recovered from E. coli and chemically coupled to form F(ab′)2 fragments (Carter et al (1992) Bio/Technology 10:163-167), or isolated directly from recombinant host cell culture. The anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), may be a (scFv) single chain Fv fragment (WO 93/16185; U.S. Pat. No. 5,571,894; U.S. Pat. No. 5,587,458). The anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), fragment may also be a “linear antibody” (U.S. Pat. No. 5,641,870). Such linear antibody fragments may be monospecific or bispecific.
The description below relates primarily to production of anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), by culturing cells transformed or transfected with a vector containing anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40)-encoding nucleic acid. DNA encoding anti-TAHO antibodies may be obtained from a cDNA library prepared from tissue believed to possess the anti-TAHO antibody mRNA and to express it at a detectable level. Accordingly, human anti-TAHO antibody or TAHO polypeptide DNA can be conveniently obtained from a cDNA library prepared from human tissue. The anti-TAHO antibody-encoding gene may also be obtained from a genomic library or by known synthetic procedures (e.g., automated nucleic acid synthesis).
The design, selection, and preparation methods of the invention enable cysteine engineered anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), which are reactive with electrophilic functionality. These methods further enable antibody conjugate compounds such as antibody-drug conjugate (ADC) compounds with drug molecules at designated, designed, selective sites. Reactive cysteine residues on an antibody surface allow specifically conjugating a drug moiety through a thiol reactive group such as maleimide or haloacetyl. The nucleophilic reactivity of the thiol functionality of a Cys residue to a maleimide group is about 1000 times higher compared to any other amino acid functionality in a protein, such as amino group of lysine residues or the N-terminal amino group. Thiol specific functionality in iodoacetyl and maleimide reagents may react with amine groups, but higher pH (>9.0) and longer reaction times are required (Garman, 1997, Non-Radioactive Labelling: A Practical Approach, Academic Press, London). The amount of free thiol in a protein may be estimated by the standard Ellman's assay. Immunoglobulin M is an example of a disulfide-linked pentamer, while immunoglobulin G is an example of a protein with internal disulfide bridges bonding the subunits together. In proteins such as this, reduction of the disulfide bonds with a reagent such as dithiothreitol (DTT) or selenol (Singh et al (2002) Anal. Biochem. 304:147-156) is required to generate the reactive free thiol. This approach may result in loss of antibody tertiary structure and antigen binding specificity.
The PHESELECTOR (Phage ELISA for Selection of Reactive Thiols) Assay allows for detection of reactive cysteine groups in antibodies in an ELISA phage format thereby assisting in the design of cysteine engineered antibodies (WO 2006/034488; US 2007/0092940). The cysteine engineered antibody is coated on well surfaces, followed by incubation with phage particles, addition of HRP labeled secondary antibody, and absorbance detection. Mutant proteins displayed on phage may be screened in a rapid, robust, and high-throughput manner. Libraries of cysteine engineered antibodies can be produced and subjected to binding selection using the same approach to identify appropriately reactive sites of free Cys incorporation from random protein-phage libraries of antibodies or other proteins. This technique includes reacting cysteine mutant proteins displayed on phage with an affinity reagent or reporter group which is also thiol-reactive.
The PHESELECTOR assay allows screening of reactive thiol groups in antibodies. Identification of the A118C variant by this method is exemplary. The entire Fab molecule may be effectively searched to identify more ThioFab variants with reactive thiol groups. A parameter, fractional surface accessibility, was employed to identify and quantitate the accessibility of solvent to the amino acid residues in a polypeptide. The surface accessibility can be expressed as the surface area (Å2) that can be contacted by a solvent molecule, e.g. water. The occupied space of water is approximated as a 1.4 Å radius sphere. Software is freely available or licensable (Secretary to CCP4, Daresbury Laboratory, Warrington, WA4 4AD, United Kingdom, Fax: (+44) 1925 603825) as the CCP4 Suite of crystallography programs which employ algorithms to calculate the surface accessibility of each amino acid of a protein with known x-ray crystallography derived coordinates (“The CCP4 Suite: Programs for Protein Crystallography” (1994) Acta. Cryst. D50:760-763). Two exemplary software modules that perform surface accessibility calculations are “AREAIMOL” and “SURFACE”, based on the algorithms of B. Lee and F. M. Richards (1971) J. Mol. Biol. 55:379-400. AREAIMOL defines the solvent accessible surface of a protein as the locus of the centre of a probe sphere (representing a solvent molecule) as it rolls over the Van der Waals surface of the protein. AREAIMOL calculates the solvent accessible surface area by generating surface points on an extended sphere about each atom (at a distance from the atom centre equal to the sum of the atom and probe radii), and eliminating those that lie within equivalent spheres associated with neighboring atoms. AREAIMOL finds the solvent accessible area of atoms in a PDB coordinate file, and summarizes the accessible area by residue, by chain and for the whole molecule. Accessible areas (or area differences) for individual atoms can be written to a pseudo-PDB output file. AREAIMOL assumes a single radius for each element, and only recognizes a limited number of different elements.
AREAIMOL and SURFACE report absolute accessibilities, i.e. the number of square Angstroms (Å). Fractional surface accessibility is calculated by reference to a standard state relevant for an amino acid within a polypeptide. The reference state is tripeptide Gly-X-Gly, where X is the amino acid of interest, and the reference state should be an ‘extended’ conformation, i.e. like those in beta-strands. The extended conformation maximizes the accessibility of X. A calculated accessible area is divided by the accessible area in a Gly-X-Gly tripeptide reference state and reports the quotient, which is the fractional accessibility. Percent accessibility is fractional accessibility multiplied by 100. Another exemplary algorithm for calculating surface accessibility is based on the SOLV module of the program xsae (Broger, C., F. Hoffman-LaRoche, Basel) which calculates fractional accessibility of an amino acid residue to a water sphere based on the X-ray coordinates of the polypeptide. The fractional surface accessibility for every amino acid in an antibody may be calculated using available crystal structure information (Eigenbrot et al. (1993) J Mol. Biol. 229:969-995).
DNA encoding the cysteine engineered antibodies is readily isolated and sequenced using conventional procedures (e.g., by using oligonucleotide probes that are capable of binding specifically to genes encoding the heavy and light chains of murine antibodies). The hybridoma cells serve as a source of such DNA. Once isolated, the DNA may be placed into expression vectors, which are then transfected into host cells such as E. coli cells, simian COS cells, Chinese Hamster Ovary (CHO) cells, or other mammalian host cells, such as myeloma cells (U.S. Pat. No. 5,807,715; US 2005/0048572; US 2004/0229310) that do not otherwise produce the antibody protein, to obtain the synthesis of monoclonal antibodies in the recombinant host cells.
After design and selection, cysteine engineered antibodies, e.g. ThioFabs, with the engineered, highly reactive unpaired Cys residues, “free cysteine amino acids”, may be produced by: (i) expression in a bacterial, e.g. E. coli, system (Skerra et al (1993) Curr. Opinion in Immunol. 5:256-262; Plückthun (1992) Immunol. Revs. 130:151-188) or a mammalian cell culture system (WO 01/00245), e.g. Chinese Hamster Ovary cells (CHO); and (ii) purification using common protein purification techniques (Lowman et al (1991) J. Biol. Chem. 266(17):10982-10988).
The engineered Cys thiol groups react with electrophilic linker reagents and drug-linker intermediates to form cysteine engineered antibody drug conjugates and other labelled cysteine engineered antibodies. Cys residues of cysteine engineered antibodies, and present in the parent antibodies, which are paired and form interchain and intrachain disulfide bonds do not have any reactive thiol groups (unless treated with a reducing agent) and do not react with electrophilic linker reagents or drug-linker intermediates. The newly engineered Cys residue, can remain unpaired, and able to react with, i.e. conjugate to, an electrophilic linker reagent or drug-linker intermediate, such as a drug-maleimide. Exemplary drug-linker intermediates include: MC-MMAE, MC-MMAF, MC-vc-PAB-MMAE, and MC-vc-PAB-MMAF. The structure positions of the engineered Cys residues of the heavy and light chains are numbered according to a sequential numbering system. This sequential numbering system is correlated to the Kabat numbering system (Kabat et al., (1991) Sequences of Proteins of Immunological Interest, 5th Ed. Public Health Service, National Institutes of Health, Bethesda, Md.) starting at the N-terminus, differs from the Kabat numbering scheme (bottom row) by insertions noted by a,b,c. Using the Kabat numbering system, the actual linear amino acid sequence may contain fewer or additional amino acids corresponding to a shortening of, or insertion into, a FR or CDR of the variable domain. The cysteine engineered heavy chain variant sites are identified by the sequential numbering and Kabat numbering schemes.
In one embodiment, the cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), is prepared by a process comprising:
(a) replacing one or more amino acid residues of a parent anti-TAHO antibody by cysteine; and
(b) determining the thiol reactivity of the cysteine engineered anti-TAHO antibody by reacting the cysteine engineered antibody with a thiol-reactive reagent.
The cysteine engineered antibody may be more reactive than the parent antibody with the thiol-reactive reagent.
The free cysteine amino acid residues may be located in the heavy or light chains, or in the constant or variable domains. Antibody fragments, e.g. Fab, may also be engineered with one or more cysteine amino acids replacing amino acids of the antibody fragment, to form cysteine engineered antibody fragments.
Another embodiment of the invention provides a method of preparing (making) a cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), comprising:
(a) introducing one or more cysteine amino acids into a parent anti-TAHO antibody in order to generate the cysteine engineered anti-TAHO antibody; and
(b) determining the thiol reactivity of the cysteine engineered antibody with a thiol-reactive reagent; wherein the cysteine engineered antibody is more reactive than the parent antibody with the thiol-reactive reagent.
Step (a) of the method of preparing a cysteine engineered antibody may comprise:
Step (b) of the method of preparing a cysteine engineered antibody may comprise expressing the cysteine engineered antibody on a viral particle selected from a phage or a phagemid particle.
Step (b) of the method of preparing a cysteine engineered antibody may also comprise:
Another embodiment of the invention is a method of screening cysteine engineered antibodies with highly reactive, unpaired cysteine amino acids for thiol reactivity comprising:
(a) introducing one or more cysteine amino acids into a parent antibody in order to generate a cysteine engineered antibody;
(b) reacting the cysteine engineered antibody with a thiol-reactive affinity reagent to generate an affinity labelled, cysteine engineered antibody; and
(c) measuring the binding of the affinity labelled, cysteine engineered antibody to a capture media; and
(d) determining the thiol reactivity of the cysteine engineered antibody with the thiol-reactive reagent.
Step (a) of the method of screening cysteine engineered antibodies may comprise:
Step (b) of the method of screening cysteine engineered antibodies may comprise expressing the cysteine engineered antibody on a viral particle selected from a phage or a phagemid particle.
Step (b) of the method of screening cysteine engineered antibodies may also comprise:
b. Cysteine Engineering of Anti-TAHO IgG Variants
Cysteine was introduced at the heavy chain 118 (EU numbering) (equivalent to heavy chain position 118, sequential numbering) site into the full-length, chimeric parent monoclonal anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), or at the light chain 205 (Kabat numbering) (equivalent to light chain position 208, sequential numbering) site into the full-length, chimeric parental monoclonal anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), by the cysteine engineering methods described herein.
Cysteine engineered antibodies with cysteine at heavy chain 118 (EU numbering) generated were: (a) thio-chSN8-HC(A118C) with heavy chain sequence (SEQ ID NO: 54) and light chain sequence (SEQ ID NO: 55),
Cysteine engineered antibodies with cysteine at light chain 205 (Kabat numbering) generated were: (a) thio-chSN8-LC(V205C) with heavy chain sequence (SEQ ID NO: 52) and light chain sequence (SEQ ID NO: 53),
These cysteine engineered monoclonal antibodies were expressed in CHO (Chinese Hamster Ovary) cells by transient fermentation in media containing 1 mM cysteine.
According to one embodiment, chimeric SN8 cysteine engineered anti-human CD79b (TAHO5) antibodies comprise one or more of the following heavy chain sequences with a free cysteine amino acid (SEQ ID NOs: 63-71, Table 6).
According to one embodiment, anti-cynoCD79b (TAHO40) (ch10D10) cysteine engineered anti-cynoCD79b (TAHO40) antibodies comprise one or more of the following heavy chain sequences with a free cysteine amino acid (SEQ ID NOs: 72-80, Table 7).
According to one embodiment, chimeric SN8 cysteine-engineered anti-human CD79b (TAHO5) antibodies comprise one or more of rhe following light chain sequences with a free cysteine amino acid (SEQ ID NOs: 81-87, Table 8).
According to one embodiment, anti-cynoCD79b (TAHO40) (ch10D10) cysteine-engineered anti-cynoCD79b (TAHO40) antibodies comprise one or more of rhe following light chain sequences with a free cysteine amino acid (SEQ ID NOs: 88-94, Table 9).
c. Labelled Cysteine Engineered Anti-TAHO Antibodies
Cysteine engineered anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), may be site-specifically and efficiently coupled with a thiol-reactive reagent. The thiol-reactive reagent may be a multifunctional linker reagent, a capture, i.e. affinity, label reagent (e.g. a biotin-linker reagent), a detection label (e.g. a fluorophore reagent), a solid phase immobilization reagent (e.g. SEPHAROSE™, polystyrene, or glass), or a drug-linker intermediate. One example of a thiol-reactive reagent is N-ethyl maleimide (NEM). In an exemplary embodiment, reaction of a ThioFab with a biotin-linker reagent provides a biotinylated ThioFab by which the presence and reactivity of the engineered cysteine residue may be detected and measured. Reaction of a ThioFab with a multifunctional linker reagent provides a ThioFab with a functionalized linker which may be further reacted with a drug moiety reagent or other label. Reaction of a ThioFab with a drug-linker intermediate provides a ThioFab drug conjugate.
The exemplary methods described here may be applied generally to the identification and production of antibodies, and more generally, to other proteins through application of the design and screening steps described herein.
Such an approach may be applied to the conjugation of other thiol-reactive reagents in which the reactive group is, for example, a maleimide, an iodoacetamide, a pyridyl disulfide, or other thiol-reactive conjugation partner (Haugland, 2003, Molecular Probes Handbook of Fluorescent Probes and Research Chemicals, Molecular Probes, Inc.; Brinkley, 1992, Bioconjugate Chem. 3:2; Garman, 1997, Non-Radioactive Labelling: A Practical Approach, Academic Press, London; Means (1990) Bioconjugate Chem. 1:2; Hermanson, G. in Bioconjugate Techniques (1996) Academic Press, San Diego, pp. 40-55, 643-671). The thiol-reactive reagent may be a drug moiety, a fluorophore such as a fluorescent dye like fluorescein or rhodamine, a chelating agent for an imaging or radiotherapeutic metal, a peptidyl or non-peptidyl label or detection tag, or a clearance-modifying agent such as various isomers of polyethylene glycol, a peptide that binds to a third component, or another carbohydrate or lipophilic agent.
d. Uses of Cysteine Engineered Anti-TAHO Antibodies
Cysteine engineered anti-TAHO antibodies, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), and conjugates thereof may find use as therapeutic and/or diagnostic agents. The present invention further provides methods of preventing, managing, treating or ameliorating one or more symptoms associated with a B-cell related disorder. In particular, the present invention provides methods of preventing, managing, treating, or ameliorating one or more symptoms associated with a cell proliferative disorder, such as cancer, e.g., lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma. The present invention still further provides methods for diagnosing a CD79b related disorder or predisposition to developing such a disorder, as well as methods for identifying antibodies, and antigen-binding fragments of antibodies, that preferentially bind B cell-associated CD79b polypeptides.
Another embodiment of the present invention is directed to the use of a cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), for the preparation of a medicament useful in the treatment of a condition which is responsive to a B cell related disorder.
e. Cysteine Engineered Antibody Drug Conjugates (Thio-Antibody Drug Conjugates (TDCs))
Another aspect of the invention is an antibody-drug conjugate compound comprising a cysteine engineered anti-TAHO antibody (Ab), such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), and an auristatin drug moiety (D) wherein the cysteine engineered antibody is attached through one or more free cysteine amino acids by a linker moiety (L) to D; the compound having Formula I:
Ab-(L-D)p I
where p is 1, 2, 3, or 4; and wherein the cysteine engineered antibody is prepared by a process comprising replacing one or more amino acid residues of a parent anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), by one or more free cysteine amino acids.
Another aspect of the invention is a composition comprising a mixture of antibody-drug compounds of Formula I where the average drug loading per antibody is about 2 to about 5, or about 3 to about 4.
Potential advantages of cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), drug conjugates include improved safety (larger therapeutic index), improved PK parameters, the antibody inter-chain disulfide bonds are retained which may stabilize the conjugate and retain its active binding conformation, the sites of drug conjugation are defined, and the preparation of cysteine engineered antibody drug conjugates from conjugation of cysteine engineered antibodies to drug-linker reagents results in a more homogeneous product.
Linkers
“Linker”, “Linker Unit”, or “link” means a chemical moiety comprising a covalent bond or a chain of atoms that covalently attaches an antibody to a drug moiety. In various embodiments, a linker is specified as L. A “Linker” (L) is a bifunctional or multifunctional moiety which can be used to link one or more Drug moieties (D) and an antibody unit (Ab) to form antibody-drug conjugates (ADC) of Formula I. Antibody-drug conjugates (ADC) can be conveniently prepared using a Linker having reactive functionality for binding to the Drug and to the Antibody. A cysteine thiol of a cysteine engineered antibody (Ab) can form a bond with an electrophilic functional group of a linker reagent, a drug moiety or drug-linker intermediate.
In one aspect, a Linker has a reactive site which has an electrophilic group that is reactive to a nucleophilic cysteine present on an antibody. The cysteine thiol of the antibody is reactive with an electrophilic group on a Linker and forms a covalent bond to a Linker. Useful electrophilic groups include, but are not limited to, maleimide and haloacetamide groups.
Linkers include a divalent radical such as an alkyldiyl, an arylene, a heteroarylene, moieties such as: —(CR2)nO(CR2)n—, repeating units of alkyloxy (e.g. polyethylenoxy, PEG, polymethyleneoxy) and alkylamino (e.g. polyethyleneamino, Jeffamine™); and diacid ester and amides including succinate, succinamide, diglycolate, malonate, and caproamide.
Cysteine engineered antibodies react with linker reagents or drug-linker intermediates, with electrophilic functional groups such as maleimide or α-halo carbonyl, according to the conjugation method at page 766 of Klussman, et al (2004), Bioconjugate Chemistry 15(4):765-773, and according to the protocol of Example 18.
The linker may be composed of one or more linker components. Exemplary linker components include 6-maleimidocaproyl (“MC”), maleimidopropanoyl (“MP”), valine-citrulline (“val-cit” or “vc”), alanine-phenylalanine (“ala-phe” or “af”), p-aminobenzyloxycarbonyl (“PAB”), N-succinimidyl 4-(2-pyridylthio) pentanoate (“SPP”), N-succinimidyl 4-(N-maleimidomethyl)cyclohexane-1 carboxylate (“SMCC”), N-Succinimidyl (4-iodo-acetyl)aminobenzoate (“SIAB”), ethyleneoxy —CH2CH2O— as one or more repeating units (“EO” or “PEO”). Additional linker components are known in the art and some are described herein.
In one embodiment, linker L of an ADC has the formula:
-Aa-Ww—Yy—
wherein:
-A- is a Stretcher unit covalently attached to a cysteine thiol of the antibody (Ab);
a is 0 or 1;
each —W— is independently an Amino Acid unit;
w is independently an integer ranging from 0 to 12;
—Y— is a Spacer unit covalently attached to the drug moiety; and
y is 0, 1 or 2.
Stretcher Unit
The Stretcher unit (-A-), when present, is capable of linking an antibody unit to an amino acid unit (—W—). In this regard an antibody (Ab) has a functional group that can form a bond with a functional group of a Stretcher. Useful functional groups that can be present on an antibody, either naturally or via chemical manipulation include, but are not limited to, sulfhydryl (—SH), amino, hydroxyl, carboxy, the anomeric hydroxyl group of a carbohydrate, and carboxyl. In one aspect, the antibody functional groups are sulfhydryl or amino. Sulfhydryl groups can be generated by reduction of an intramolecular disulfide bond of an antibody. Alternatively, sulfhydryl groups can be generated by reaction of an amino group of a lysine moiety of an antibody using 2-iminothiolane (Traut's reagent) or another sulfhydryl generating reagent. In one embodiment, an antibody (Ab) has a free cysteine thiol group that can form a bond with an electrophilic functional group of a Stretcher Unit. Exemplary stretcher units in Formula I conjugates are depicted by Formulas II and III, wherein Ab-, —W—, —Y—, -D, w and y are as defined above, and R17 is a divalent radical selected from (CH2)r, C3-C8 carbocyclyl, O—(CH2)r, arylene, (CH2)r-arylene, -arylene-(CH2)n—, (CH2)r—(C3-C8 carbocyclyl), (C3-C8 carbocyclyl)-(CH2)r, C3-C8 heterocyclyl, (CH2)r—(C3-C8 heterocyclyl), —(C3-C8 heterocyclyl)-(CH2)r—, —(CH2)rC(O)NRb(CH2)r—, —(CH2CH2O)r—, —(CH2CH2O)r—CH2—, —(CH2)rC(O)NRb(CH2CH2O)r, —(CH2)rC(O)NRb(CH2CH2O)r—CH2—, —(CH2CH2O)rC(O)NRb(CH2CH2O)r—, —(CH2CH2O)rC(O)NRb(CH2CH2O)r—CH2—, and —(CH2CH2O)rC(O)NRb(CH2)r—; where Rb is H, C1-C6 alkyl, phenyl, or benzyl; and r is independently an integer ranging from 1-10.
Arylene includes divalent aromatic hydrocarbon radicals of 6-20 carbon atoms derived by the removal of two hydrogen atoms from the aromatic ring system. Typical arylene groups include, but are not limited to, radicals derived from benzene, substituted benzene, naphthalene, anthracene, biphenyl, and the like.
Heterocyclyl groups include a ring system in which one or more ring atoms is a heteroatom, e.g. nitrogen, oxygen, and sulfur. The heterocycle radical comprises 1 to 20 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S. A heterocycle may be a monocycle having 3 to 7 ring members (2 to 6 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S) or a bicycle having 7 to 10 ring members (4 to 9 carbon atoms and 1 to 3 heteroatoms selected from N, O, P, and S), for example: a bicyclo [4,5], [5,5], [5,6], or [6,6] system. Heterocycles are described in Paquette, Leo A.; “Principles of Modern Heterocyclic Chemistry” (W. A. Benjamin, New York, 1968), particularly Chapters 1, 3, 4, 6, 7, and 9; “The Chemistry of Heterocyclic Compounds, A series of Monographs” (John Wiley & Sons, New York, 1950 to present), in particular Volumes 13, 14, 16, 19, and 28; and J. Am. Chem. Soc. (1960) 82:5566.
Examples of heterocycles include by way of example and not limitation pyridyl, dihydroypyridyl, tetrahydropyridyl (piperidyl), thiazolyl, tetrahydrothiophenyl, sulfur oxidized tetrahydrothiophenyl, pyrimidinyl, furanyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, tetrazolyl, benzofuranyl, thianaphthalenyl, indolyl, indolenyl, quinolinyl, isoquinolinyl, benzimidazolyl, piperidinyl, 4-piperidonyl, pyrrolidinyl, 2-pyrrolidonyl, pyrrolinyl, tetrahydrofuranyl, bis-tetrahydrofuranyl, tetrahydropyranyl, bis-tetrahydropyranyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, octahydroisoquinolinyl, azocinyl, triazinyl, 6H-1,2,5-thiadiazinyl, 2H,6H-1,5,2-dithiazinyl, thienyl, thianthrenyl, pyranyl, isobenzofuranyl, chromenyl, xanthenyl, phenoxathinyl, 2H-pyrrolyl, isothiazolyl, isoxazolyl, pyrazinyl, pyridazinyl, indolizinyl, isoindolyl, 3H-indolyl, 1H-indazolyl, purinyl, 4H-quinolizinyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, 4Ah-carbazolyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl, pyrimidinyl, phenanthrolinyl, phenazinyl, phenothiazinyl, furazanyl, phenoxazinyl, isochromanyl, chromanyl, imidazolidinyl, imidazolinyl, pyrazolidinyl, pyrazolinyl, piperazinyl, indolinyl, isoindolinyl, quinuclidinyl, morpholinyl, oxazolidinyl, benzotriaiolyl, benzisoxazolyl, oxindolyl, benzoxazolinyl, and isatinoyl.
Carbocyclyl groups include a saturated or unsaturated ring having 3 to 7 carbon atoms as a monocycle or 7 to 12 carbon atoms as a bicycle. Monocyclic carbocycles have 3 to 6 ring atoms, still more typically 5 or 6 ring atoms. Bicyclic carbocycles have 7 to 12 ring atoms, e.g. arranged as a bicyclo [4,5], [5,5], [5,6] or [6,6] system, or 9 or 10 ring atoms arranged as a bicyclo [5,6] or [6,6] system. Examples of monocyclic carbocycles include cyclopropyl, cyclobutyl, cyclopentyl, 1-cyclopent-1-enyl, 1-cyclopent-2-enyl, 1-cyclopent-3-enyl, cyclohexyl, 1-cyclohex-1-enyl, 1-cyclohex-2-enyl, 1-cyclohex-3-enyl, cycloheptyl, and cyclooctyl.
It is to be understood from all the exemplary embodiments of Formula I ADC such as II-VI, that even where not denoted expressly, from 1 to 4 drug moieties are linked to an antibody (p=1-4), depending on the number of engineered cysteine residues.
An illustrative Formula II Stretcher unit is derived from maleimido-caproyl (MC) wherein R17 is —(CH2)5—:
An illustrative Stretcher unit of Formula II, and is derived from maleimido-propanoyl (MP) wherein R17 is —(CH2)2—:
Another illustrative Stretcher unit of Formula II wherein R17 is —(CH2CH2O)r—CH2— and r is 2:
Another illustrative Stretcher unit of Formula II wherein R17 is —(CH2)rC(O)NRb(CH2CH2O)r—CH2— where Rb is H and each r is 2:
An illustrative Stretcher unit of Formula III wherein R17 is —(CH2)5—:
In another embodiment, the Stretcher unit is linked to the cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), via a disulfide bond between the engineered cysteine sulfur atom of the antibody and a sulfur atom of the Stretcher unit. A representative Stretcher unit of this embodiment is depicted by Formula IV, wherein R7, Ab-, —W—, —Y—, -D, w and y are as defined above.
In yet another embodiment, the reactive group of the Stretcher contains a thiol-reactive functional group that can form a bond with a free cysteine thiol of an antibody. Examples of thiol-reaction functional groups include, but are not limited to, maleimide, α-haloacetyl, activated esters such as succinimide esters, 4-nitrophenyl esters, pentafluorophenyl esters, tetrafluorophenyl esters, anhydrides, acid chlorides, sulfonyl chlorides, isocyanates and isothiocyanates. Representative Stretcher units of this embodiment are depicted by Formulas Va and Vb, wherein —R17—, Ab-, —W—, —Y—, -D, w and y are as defined above;
In another embodiment, the linker may be a dendritic type linker for covalent attachment of more than one drug, moiety through a branching, multifunctional linker moiety to an antibody (Sun et al (2002) Bioorganic & Medicinal Chemistry Letters 12:2213-2215; Sun et al (2003) Bioorganic & Medicinal Chemistry 11:1761-1768; King (2002) Tetrahedron Letters 43:1987-1990). Dendritic linkers can increase the molar ratio of drug to antibody, i.e. loading, which is related to the potency of the ADC. Thus, where a cysteine engineered antibody bears only one reactive cysteine thiol group, a multitude of drug moieties may be attached through a dendritic linker.
Amino Acid Unit
The linker may comprise amino acid residues. The Amino Acid unit (—Ww—), when present, links the antibody (Ab) to the drug moiety (D) of the cysteine engineered antibody-drug conjugate (ADC) of the invention.
—Ww— is a dipeptide, tripeptide, tetrapeptide, pentapeptide, hexapeptide, heptapeptide, octapeptide, nonapeptide, decapeptide, undecapeptide or dodecapeptide unit. Amino acid residues which comprise the Amino Acid unit include those occurring naturally, as well as minor amino acids and non-naturally occurring amino acid analogs, such as citrulline. Each —W— unit independently has the formula denoted below in the square brackets, and w is an integer ranging from 0 to 12:
wherein R19 is hydrogen, methyl, isopropyl, isobutyl, sec-butyl, benzyl, p-hydroxybenzyl, —CH2OH, —CH(OH)CH3, —CH2CH2SCH3, —CH2CONH2, —CH2COOH, —CH2CH2CONH2, —CH2CH2COOH, —(CH2)3NHC(═NH)NH2, —(CH2)3NH2, —(CH2)3NHCOCH3, —(CH2)3NHCHO, —(CH2)4NHC(═NH)NH2, —(CH2)4NH2, —(CH2)4NHCOCH3, —(CH2)4NHCHO, —(CH2)3NHCONH2, —(CH2)4NHCONH2, —CH2CH2CH(OH)CH2NH2, 2-pyridylmethyl-, 3-pyridylmethyl-, 4-pyridylmethyl-, phenyl, cyclohexyl,
When R19 is other than hydrogen, the carbon atom to which R19 is attached is chiral. Each carbon atom to which R19 is attached is independently in the (S) or (R) configuration, or a racemic mixture. Amino acid units may thus be enantiomerically pure, racemic, or diastereomeric.
Exemplary —Ww— Amino Acid units include a dipeptide, a tripeptide, a tetrapeptide or a pentapeptide. Exemplary dipeptides include: valine-citruiline (vc or val-cit), alanine-phenylalanine (af or ala-phe). Exemplary tripeptides include: glycine-valine-citrulline (gly-val-cit) and glycine-glycine-glycine (gly-gly-gly). Amino acid residues which comprise an amino acid linker component include those occurring naturally, as well as minor amino acids and non-naturally occurring amino acid analogs, such as citrulline.
The Amino Acid unit can be enzymatically cleaved by one or more enzymes, including a tumor-associated protease, to liberate the Drug moiety (-D), which in one embodiment is protonated in vivo upon release to provide a Drug (D). Amino acid linker components can be designed and optimized in their selectivity for enzymatic cleavage by a particular enzymes, for example, a tumor-associated protease, cathepsin B, C and D, or a plasmin protease.
Spacer Unit
The Spacer unit (—Yy—), when present (y=1 or 2), links an Amino Acid unit (—Ww—) to the drug moiety (D) when an Amino Acid unit is present (w=1-12). Alternately, the Spacer unit links the Stretcher unit to the Drug moiety when the Amino Acid unit is absent. The Spacer unit also links the drug moiety to the antibody unit when both the Amino Acid unit and Stretcher unit are absent (w, y=0). Spacer units are of two general types: self-immolative and non self-immolative. A non self-immolative Spacer unit is one in which part or all of the Spacer unit remains bound to the Drug moiety after cleavage, particularly enzymatic, of an Amino Acid unit from the antibody-drug conjugate or the Drug moiety-linker. When an ADC containing a glycine-glycine Spacer unit or a glycine Spacer unit undergoes enzymatic cleavage via a tumor-cell associated-protease, a cancer-cell-associated protease or a lymphocyte-associated protease, a glycine-glycine-Drug moiety or a glycine-Drug moiety is cleaved from Ab-Aa-Ww—. In one embodiment, an independent hydrolysis reaction takes place within the target cell, cleaving the glycine-Drug moiety bond and liberating the Drug.
In another embodiment, —Yy— is a p-aminobenzylcarbamoyl (PAB) unit whose phenylene portion is substituted with Qm wherein Q is —C1-C8 alkyl, —O—(C1-C8 alkyl), -halogen,-nitro or -cyano; and m is an integer ranging from 0-4.
Exemplary embodiments of a non self-immolative Spacer unit (—Y—) are: -Gly-Gly-; -Gly-; -Ala-Phe-; -Val-Cit-.
In one embodiment, a Drug moiety-linker or an ADC is provided in which the Spacer unit is absent (y=0), or a pharmaceutically acceptable salt or solvate thereof.
Alternatively, an ADC containing a self-immolative Spacer unit can release -D. In one embodiment, —Y— is a PAB group that is linked to —Ww— via the amino nitrogen atom of the PAB group, and connected directly to -D via a carbonate, carbamate or ether group, where the ADC has the exemplary structure:
wherein Q is —C1-C8 alkyl, —O—(C1-C8 alkyl), -halogen, -nitro or -cyano; m is an integer ranging from 0-4; and p ranges from 1 to 4.
Other examples of self-immolative spacers include, but are not limited to, aromatic compounds that are electronically similar to the PAB group such as 2-aminoimidazol-5-methanol derivatives (Hay et al. (1999) Bioorg. Med. Chem. Lett. 9:2237), heterocyclic PAB analogs (US 2005/0256030), beta-glucuronide (WO 2007/011968), and ortho or para-aminobenzylacetals. Spacers can be used that undergo cyclization upon amide bond hydrolysis, such as substituted and unsubstituted 4-aminobutyric acid amides (Rodrigues et al (1995) Chemistry Biology 2:223), appropriately substituted bicyclo[2.2.1] and bicyclo[2.2.2] ring systems (Storm et al (1972) J. Amer. Chem. Soc. 94:5815) and 2-aminophenylpropionic acid amides (Amsberry, et al (1990) J. Org. Chem. 55:5867). Elimination of amine-containing drugs that are substituted at glycine (Kingsbury et al (1984) J. Med. Chem. 27:1447) are also examples of self-immolative spacer useful in ADCs.
Exemplary Spacer units (—Yy—) are represented by Formulas X-XII:
Dendritic Linkers
In another embodiment, linker L may be a dendritic type linker for covalent attachment of more than one drug moiety through a branching, multifunctional linker moiety to an antibody (Sun et al (2002) Bioorganic & Medicinal Chemistry Letters 12:2213-2215; Sun et al (2003) Bioorganic & Medicinal Chemistry 11:1761-1768). Dendritic linkers can increase the molar ratio of drug to antibody, i.e. loading, which is related to the potency of the ADC. Thus, where a cysteine engineered antibody bears only one reactive cysteine thiol group, a multitude of drug moieties may be attached through a dendritic linker. Exemplary embodiments of branched, dendritic linkers include 2,6-bis(hydroxymethyl)-p-cresol and 2,4,6-tris(hydroxymethyl)-phenol dendrimer units (WO 2004/01993; Szalai et al (2003) J. Amer. Chem. Soc. 125:15688-15689; Shamis et al (2004) J. Amer. Chem. Soc. 126:1726-1731; Amir et al (2003) Angew. Chem. Int. Ed. 42:4494-4499).
In one embodiment, the Spacer unit is a branched bis(hydroxymethyl)styrene (BHMS), which can be used to incorporate and release multiple drugs, having the structure:
comprising a 2-(4-aminobenzylidene)propane-1,3-diol dendrimer unit (WO 2004/043493; de Groot et al (2003) Angew. Chem. Int. Ed. 42:4490-4494), wherein Q is —C1-C8 alkyl, —O—(C1-C8 alkyl), -halogen, -nitro or -cyano; m is an integer ranging from 0-4; n is 0 or 1; and p ranges ranging from 1 to 4.
Exemplary embodiments of the Formula I antibody-drug conjugate compounds include XIIIa (MC), XIIIb (val-cit), XIIIc (MC-val-cit), and XIIId (MC-val-cit-PAB):
Other exemplary embodiments of the Formula Ia antibody-drug conjugate compounds include XIVa-e:
where X is:
Y is:
and R is independently H or C1-C6 alkyl; and n is 1 to 12.
In another embodiment, a Linker has a reactive functional group which has a nucleophilic group that is reactive to an electrophilic group present on an antibody. Useful electrophilic groups on an antibody include, but are not limited to, aldehyde and ketone carbonyl groups. The heteroatom of a nucleophilic group of a Linker can react with an electrophilic group on an antibody and form a covalent bond to an antibody unit. Useful nucleophilic groups on a Linker include, but are not limited to, hydrazide, oxime, amino, hydrazine, thiosemicarbazone, hydrazine carboxylate, and arylhydrazide. The electrophilic group on an antibody provides a convenient site for attachment to a Linker.
Typically, peptide-type Linkers can be prepared by forming a peptide bond between two or more amino acids and/or peptide fragments. Such peptide bonds can be prepared, for example, according to the liquid phase synthesis method (E. Schröder and K. Lübke (1965) “The Peptides”, volume 1, pp 76-136, Academic Press) which is well known in the field of peptide chemistry. Linker intermediates may be assembled with any combination or sequence of reactions including Spacer, Stretcher, and Amino Acid units. The Spacer, Stretcher, and Amino Acid units may employ reactive functional groups which are electrophilic, nucleophilic, or free radical in nature. Reactive functional groups include, but are not limited to carboxyls, hydroxyls, para-nitrophenylcarbonate, isothiocyanate, and leaving groups, such as O-mesyl, O-tosyl, —Cl, —Br, —I; or maleimide.
example, a charged substituent such as sulfonate (—SO3−) or ammonium, may increase water solubility of the reagent and facilitate the coupling reaction of the linker reagent with the antibody or the drug moiety, or facilitate the coupling reaction of Ab-L (antibody-linker intermediate) with D, or D-L (drug-linker intermediate) with Ab, depending on the synthetic route employed to prepare the ADC.
Linker Reagents
Conjugates of the antibody and auristatin may be made using a variety of bifunctional linker reagents such as N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP), succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCl), active esters (such as disuccinimidyl suberate), aldehydes (such as glutaraldehyde), bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as toluene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene).
The antibody drug conjugates may also be prepared with linker reagents: BMPEO, BMPS, EMCS, GMBS, HBVS, LC-SMCC, MBS, MPBH, SBAP, SIA, SIAB, SMPB, SMPH, sulfo-EMCS, sulfo-GMBS, sulfo-KMUS, sulfo-MBS, sulfo-SIAB, sulfo-SMCC, and sulfo-SMPB, and SVSB (succinimidyl-(4-vinylsulfone)benzoate), and including bis-maleimide reagents: DTME, BMB, BMDB, BMH, BMOE, 1,8-bis-maleimidodiethyleneglycol (BM(PEO)2), and 1,11-bis-maleimidotriethyleneglycol (BM(PEO)3), which are commercially available from Pierce Biotechnology, Inc., ThermoScientific, Rockford, Ill., and other reagent suppliers. Bis-maleimide reagents allow the attachment of the thiol group of a cysteine engineered antibody to a thiol-containing drug moiety, label, or linker intermediate, in a sequential or concurrent fashion. Other functional groups besides maleimide, which are reactive with a thiol group of a cysteine engineered antibody, drug moiety, label, or linker intermediate include iodoacetamide, bromoacetamide, vinyl pyridine, disulfide, pyridyl disulfide, isocyanate, and isothiocyanate.
Useful linker reagents can also be obtained via other commercial sources, such as Molecular Biosciences Inc.(Boulder, Colo.), or synthesized in accordance with procedures described in Toki et al (2002) J. Org. Chem. 67:1866-1872; Walker, M. A. (1995) J. Org. Chem. 60:5352-5355; Frisch et al (1996) Bioconjugate Chem. 7:180-186; U.S. Pat. No. 6,214,345; WO 02/088172; US 2003130189; US2003096743; WO 03/026577; WO 03/043583; and WO 04/032828.
Stretchers of formula (IIIa) can be introduced into a Linker by reacting the following linker reagents with the N-terminus of an Amino Acid unit:
where n is an integer ranging from 1-10 and T is —H or —SO3Na;
where n is an integer ranging from 0-3;
Stretcher units of can be introduced into a Linker by reacting the following bifunctional reagents with the N-terminus of an Amino Acid unit:
where X is Br or I.
Stretcher units of formula can also be introduced into a Linker by reacting the following bifunctional reagents with the N-terminus of an Amino Acid unit:
An exemplary valine-citrulline (val-cit or vc) dipeptide linker reagent having a maleimide Stretcher and a para-aminobenzylcarbamoyl (PAB) self-immolative Spacer has the structure:
An exemplary phe-lys(Mtr, mono-4-methoxytrityl) dipeptide linker reagent having a maleimide Stretcher unit and a PAB self-immolative Spacer unit can be prepared according to Dubowchik, et al. (1997) Tetrahedron Letters, 38:5257-60, and has the structure:
Exemplary antibody-drug conjugate compounds of the invention include:
where Val is valine; Cit is citrulline; vc is valine citrulline, p is 1, 2, 3, or 4; and Ab is a cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40).
Preparation of Cysteine Engineered Anti-TAHO Antibody-Drug Conjugates
The ADC of Formula I may be prepared by several routes, employing organic chemistry reactions, conditions, and reagents known to those skilled in the art, including: (1) reaction of a cysteine group of a cysteine engineered antibody with a linker reagent, to form antibody-linker intermediate Ab-L, via a covalent bond, followed by reaction with an activated drug moiety D; and (2) reaction of a nucleophilic group of a drug moiety with a linker reagent, to form drug-linker intermediate D-L, via a covalent bond, followed by reaction with a cysteine group of a cysteine engineered antibody. Conjugation methods (1) and (2) may be employed with a variety of cysteine engineered antibodies, drug moieties, and linkers to prepare the antibody-drug conjugates of Formula I.
Antibody cysteine thiol groups are nucleophilic and capable of reacting to form covalent bonds with electrophilic groups on linker reagents and drug-linker intermediates including: (i) active esters such as NHS esters, HOBt esters, haloformates, and acid halides; (ii) alkyl and benzyl halides, such as haloacetamides; (iii) aldehydes, ketones, carboxyl, and maleimide groups; and (iv) disulfides, including pyridyl disulfides, via sulfide exchange. Nucleophilic groups on a drug moiety include, but are not limited to: amine, thiol, hydroxyl, hydrazide, oxime, hydrazine, thiosemicarbazone, hydrazine carboxylate, and arylhydrazide groups capable of reacting to form covalent bonds with electrophilic groups on linker moieties and linker reagents.
Cysteine engineered antibodies may be made reactive for conjugation with linker reagents by treatment with a reducing agent such as DTT (Cleland's reagent, dithiothreitol) or TCEP (tris(2-carboxyethyl)phosphine hydrochloride; Getz et al (1999) Anal. Biochem. Vol 273:73-80; Soltec Ventures, Beverly, Mass.), followed by reoxidation to reform interchain and intrachain disulfide bonds (Example 17). For example, full length, cysteine engineered monoclonal antibodies (ThioMabs) expressed in CHO cells are reduced with about a 50 fold molar excess of TCEP for 3 hrs at 37° C. to reduce disulfide bonds in cysteine adducts which may form between the newly introduced cysteine residues and the cysteine present in the culture media. The reduced ThioMab is diluted and loaded onto HiTrap S column in 10 mM sodium acetate, pH 5, and eluted with PBS containing 0.3M sodium chloride. Disulfide bonds were reestablished between cysteine residues present in the parent Mab with dilute (200 nM) aqueous copper sulfate (CuSO4) at room temperature, overnight. Alternatively, dehydroascorbic acid (DHAA) is an effective oxidant to reestablish the intrachain disulfide groups of the cysteine engineered antibody after reductive cleavage of the cysteine adducts. Other oxidants, i.e. oxidizing agents, and oxidizing conditions, which are known in the art may be used. Ambient air oxidation is also effective. This mild, partial reoxidation step forms intrachain disulfides efficiently with high fidelity and preserves the thiol groups of the newly introduced cysteine residues. An approximate 10 fold excess of drug-linker intermediate, e.g. MC-vc-PAB-MMAE, was added, mixed, and let stand for about an hour at room temperature to effect conjugation and form the anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody-drug conjugate. The conjugation mixture was gel filtered and loaded and eluted through a HiTrap S column to remove excess drug-linker intermediate and other impurities.
10. Immunoliposomes
The anti-TAHO antibodies disclosed herein may also be formulated as immunoliposomes. A “liposome” is a small vesicle composed of various types of lipids, phospholipids and/or surfactant which is useful for delivery of a drug to a mammal. The components of the liposome are commonly arranged in a bilayer formation, similar to the lipid arrangement of biological membranes. Liposomes containing the antibody are prepared by methods known in the art, such as described in Epstein et al., Proc. Natl. Acad. Sci. USA 82:3688 (1985); Hwang et al., Proc. Natl. Acad. Sci. USA 77:4030 (1980); U.S. Pat. Nos. 4,485,045 and 4,544,545; and WO97/38731 published Oct. 23, 1997. Liposomes with enhanced circulation time are disclosed in U.S. Pat. No. 5,013,556.
Particularly useful liposomes can be generated by the reverse phase evaporation method with a lipid composition comprising phosphatidylcholine, cholesterol and PEG-derivatized phosphatidylethanolamine (PEG-PE). Liposomes are extruded through filters of defined pore size to yield liposomes with the desired diameter. Fab′ fragments of the antibody of the present invention can be conjugated to the liposomes as described in Martin et al., J. Biol. Chem. 257:286-288 (1982) via a disulfide interchange reaction. A chemotherapeutic agent is optionally contained within the liposome. See Gabizon et al., J. National Cancer Inst. 81(19):1484 (1989).
B. TAHO Binding Oligopeptides
TAHO binding oligopeptides of the present invention are oligopeptides that bind, preferably specifically, to a TAHO polypeptide as described herein. TAHO binding oligopeptides may be chemically synthesized using known oligopeptide synthesis methodology or may be prepared and purified using recombinant technology. TAHO binding oligopeptides are usually at least about 5 amino acids in length, alternatively at least about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100 amino acids in length or more, wherein such oligopeptides that are capable of binding, preferably specifically, to a TAHO polypeptide as described herein. TAHO binding oligopeptides may be identified without undue experimentation using well known techniques. In this regard, it is noted that techniques for screening oligopeptide libraries for oligopeptides that are capable of specifically binding to a polypeptide target are well known in the art (see, e.g., U.S. Pat. Nos. 5,556,762, 5,750,373, 4,708,871, 4,833,092, 5,223,409, 5,403,484, 5,571,689, 5,663,143; PCT Publication Nos. WO 84/03506 and WO84/03564; Geysen et al., Proc. Natl. Acad. Sci. U.S.A., 81:3998-4002 (1984); Geysen et al., Proc. Natl. Acad. Sci. U.S.A., 82:178-182 (1985); Geysen et al., in Synthetic Peptides as Antigens, 130-149 (1986); Geysen et al., J. Immunol. Meth., 102:259-274 (1987); Schoofs et al., J. Immunol., 140:611-616 (1988), Cwirla, S. E. et al. (1990) Proc. Natl. Acad. Sci. USA, 87:6378; Lowman, H. B. et al. (1991) Biochemistry, 30:10832; Clackson, T. et al. (1991) Nature, 352: 624; Marks, J. D. et al. (1991), J. Mol. Biol., 222:581; Kang, A. S. et al. (1991) Proc. Natl. Acad. Sci. USA, 88:8363, and Smith, G. P. (1991) Current Opin. Biotechnol., 2:668).
In this regard, bacteriophage (phage) display is one well known technique which allows one to screen large oligopeptide libraries to identify member(s) of those libraries which are capable of specifically binding to a polypeptide target. Phage display is a technique by which variant polypeptides are displayed as fusion proteins to the coat protein on the surface of bacteriophage particles (Scott, J. K. and Smith, G. P. (1990) Science, 249: 386). The utility of phage display lies in the fact that large libraries of selectively randomized protein variants (or randomly cloned cDNAs) can be rapidly and efficiently sorted for those sequences that bind to a target molecule with high affinity. Display of peptide (Cwirla, S. E. et al. (1990) Proc. Natl. Acad. Sci. USA, 87:6378) or protein (Lowman, H. B. et al. (1991) Biochemistry, 30:10832; Clackson, T. et al. (1991) Nature, 352: 624; Marks, J. D. et al. (1991), J. Mol. Biol., 222:581; Kang, A. S. et al. (1991) Proc. Natl. Acad. Sci. USA, 88:8363) libraries on phage have been used for screening millions of polypeptides or oligopeptides for ones with specific binding properties (Smith, G. P. (1991) Current Opin. Biotechnol., 2:668). Sorting phage libraries of random mutants requires a strategy for constructing and propagating a large number of variants, a procedure for affinity purification using the target receptor, and a means of evaluating the results of binding enrichments. U.S. Pat. Nos. 5,223,409, 5,403,484, 5,571,689, and 5,663,143.
Although most phage display methods have used filamentous phage, lambdoid phage display systems (WO 95/34683; U.S. Pat. No. 5,627,024), T4 phage display systems (Ren et al., Gene, 215: 439 (1998); Zhu et al., Cancer Research, 58(15): 3209-3214 (1998); Jiang et al., Infection & Immunity, 65(11): 4770-4777 (1997); Ren et al., Gene, 195(2):303-311 (1997); Ren, Protein Sci., 5: 1833 (1996); Efimov et al., Virus Genes, 10: 173 (1995)) and T7 phage display systems (Smith and Scott, Methods in Enzymology, 217: 228-257 (1993); U.S. Pat. No. 5,766,905) are also known.
Many other improvements and variations of the basic phage display concept have now been developed. These improvements enhance the ability of display systems to screen peptide libraries for binding to selected target molecules and to display functional proteins with the potential of screening these proteins for desired properties. Combinatorial reaction devices for phage display reactions have been developed (WO 98/14277) and phage display libraries have been used to analyze and control bimolecular interactions (WO 98/20169; WO 98/20159) and properties of constrained helical peptides (WO 98/20036). WO 97/35196 describes a method of isolating an affinity ligand in which a phage display library is contacted with one solution in which the ligand will bind to a target molecule and a second solution in which the affinity ligand will not bind to the target molecule, to selectively isolate binding ligands. WO 97/46251 describes a method of biopanning a random phage display library with an affinity purified antibody and then isolating binding phage, followed by a micropanning process using microplate wells to isolate high affinity binding phage. The use of Staphlylococcus aureus protein A as an affinity tag has also been reported (Li et al. (1998) Mol. Biotech., 9:187). WO 97/47314 describes the use of substrate subtraction libraries to distinguish enzyme specificities using a combinatorial library which may be a phage display library. A method for selecting enzymes suitable for use in detergents using phage display is described in WO 97/09446. Additional methods of selecting specific binding proteins are described in U.S. Pat. Nos. 5,498,538, 5,432,018, and WO 98/15833.
Methods of generating peptide libraries and screening these libraries are also disclosed in U.S. Pat. Nos. 5,723,286, 5,432,018, 5,580,717, 5,427,908, 5,498,530, 5,770,434, 5,734,018, 5,698,426, 5,763,192, and 5,723,323.
C. TAHO Binding Organic Molecules
TAHO binding organic molecules are organic molecules other than oligopeptides or antibodies as defined herein that bind, preferably specifically, to a TAHO polypeptide as described herein. TAHO binding organic molecules may be identified and chemically synthesized using known methodology (see, e.g., PCT Publication Nos. WO00/00823 and WO00/39585). TAHO binding organic molecules are usually less than about 2000 daltons in size, alternatively less than about 1500, 750, 500, 250 or 200 daltons in size, wherein such organic molecules that are capable of binding, preferably specifically, to a TAHO polypeptide as described herein may be identified without undue experimentation using well known techniques. In this regard, it is noted that techniques for screening organic molecule libraries for molecules that are capable of binding to a polypeptide target are well known in the art (see, e.g., PCT Publication Nos. WO00/00823 and WO00/39585). TAHO binding organic molecules may be, for example, aldehydes, ketones, oximes, hydrazones, semicarbazones, carbazides, primary amines, secondary amines, tertiary amines, N-substituted hydrazines, hydrazides, alcohols, ethers, thiols, thioethers, disulfides, carboxylic acids, esters, amides, ureas, carbamates, carbonates, ketals, thioketals, acetals, thioacetals, aryl halides, aryl sulfonates, alkyl halides, alkyl sulfonates, aromatic compounds, heterocyclic compounds, anilines, alkenes, alkynes, diols, amino alcohols, oxazolidines, oxazolines, thiazolidines, thiazolines, enamines, sulfonamides, epoxides, aziridines, isocyanates, sulfonyl chlorides, diazo compounds, acid chlorides, or the like.
D. Screening for Anti-TAHO Antibodies, TAHO Binding Oligopeptides and TAHO Binding Organic Molecules with the Desired Properties
Techniques for generating antibodies, oligopeptides and organic molecules that bind to TAHO polypeptides have been described above. One may further select antibodies, oligopeptides or other organic molecules with certain biological characteristics, as desired.
The growth inhibitory effects of an anti-TAHO antibody, oligopeptide or other organic molecule of the invention may be assessed by methods known in the art, e.g., using cells which express a TAHO polypeptide either endogenously or following transfection with the TAHO gene. For example, appropriate tumor cell lines and TAHO-transfected cells may be treated with an anti-TAHO monoclonal antibody, oligopeptide or other organic molecule of the invention at various concentrations for a few days (e.g., 2-7) days and stained with crystal violet or MTT or analyzed by some other colorimetric assay. Another method of measuring proliferation would be by comparing 3H-thymidine uptake by the cells treated in the presence or absence an anti-TAHO antibody, TAHO binding oligopeptide or TAHO binding organic molecule of the invention. After treatment, the cells are harvested and the amount of radioactivity incorporated into the DNA quantitated in a scintillation counter. Appropriate positive controls include treatment of a selected cell line with a growth inhibitory antibody known to inhibit growth of that cell line. Growth inhibition of tumor cells in vivo can be determined in various ways known in the art. The tumor cell may be one that overexpresses a TAHO polypeptide. The anti-TAHO antibody, TAHO binding oligopeptide or TAHO binding organic molecule will inhibit cell proliferation of a TAHO-expressing tumor cell in vitro or in vivo by about 25-100% compared to the untreated tumor cell, more preferably, by about 30-100%, and even more preferably by about 50-100% or 70-100%, in one embodiment, at an antibody concentration of about 0.5 to 30 μg/ml. Growth inhibition can be measured at an antibody concentration of about 0.5 to 30 μg/ml or about 0.5 nM to 200 nM in cell culture, where the growth inhibition is determined 1-10 days after exposure of the tumor cells to the antibody. The antibody is growth inhibitory in vivo if administration of the anti-TAHO antibody at about 1 μg/kg to about 100 mg/kg body weight results in reduction in tumor size or reduction of tumor cell proliferation within about 5 days to 3 months from the first administration of the antibody, preferably within about 5 to 30 days.
To select for an anti-TAHO antibody, TAHO binding oligopeptide or TAHO binding organic molecule which induces cell death, loss of membrane integrity as indicated by, e.g., propidium iodide (PI), trypan blue or 7AAD uptake may be assessed relative to control. A PI uptake assay can be performed in the absence of complement and immune effector cells. TAHO polypeptide-expressing tumor cells are incubated with medium alone or medium containing the appropriate anti-TAHO antibody (e.g., at about 10 μg/ml), TAHO binding oligopeptide or TAHO binding organic molecule. The cells are incubated for a 3 day time period. Following each treatment, cells are washed and aliquoted into 35 mm strainer-capped 12×75 tubes (1 ml per tube, 3 tubes per treatment group) for removal of cell clumps. Tubes then receive PI (10 μg/ml). Samples may be analyzed using a FACSCAN® flow cytometer and FACSCONVERT® CellQuest software (Becton Dickinson). Those anti-TAHO antibodies, TAHO binding oligopeptides or TAHO binding organic molecules that induce statistically significant levels of cell death as determined by PI uptake may be selected as cell death-inducing anti-TAHO antibodies, TAHO binding oligopeptides or TAHO binding organic molecules.
To screen for antibodies, oligopeptides or other organic molecules which bind to an epitope on a TAHO polypeptide bound by an antibody of interest, a routine cross-blocking assay such as that described in Antibodies, A Laboratory Manual, Cold Spring Harbor Laboratory, Ed Harlow and David Lane (1988), can be performed. This assay can be used to determine if a test antibody, oligopeptide or other organic molecule binds the same site or epitope as a known anti-TAHO antibody. Alternatively, or additionally, epitope mapping can be performed by methods known in the art. For example, the antibody sequence can be mutagenized such as by alanine scanning, to identify contact residues. The mutant antibody is initially tested for binding with polyclonal antibody to ensure proper folding. In a different method, peptides corresponding to different regions of a TAHO polypeptide can be used in competition assays with the test antibodies or with a test antibody and an antibody with a characterized or known epitope.
E. Antibody Dependent Enzyme Mediated Prodrug Therapy (ADEPT)
The antibodies of the present invention may also be used in ADEPT by conjugating the antibody to a prodrug-activating enzyme which converts a prodrug (e.g., a peptidyl chemotherapeutic agent, see WO81/01145) to an active anti-cancer drug. See, for example, WO 88/07378 and U.S. Pat. No. 4,975,278.
The enzyme component of the immunoconjugate useful for ADEPT includes any enzyme capable of acting on a prodrug in such a way so as to covert it into its more active, cytotoxic form.
Enzymes that are useful in the method of this invention include, but are not limited to, alkaline phosphatase useful for converting phosphate-containing prodrugs into free drugs; arylsulfatase useful for converting sulfate-containing prodrugs into free drugs; cytosine deaminase useful for converting non-toxic 5-fluorocytosine into the anti-cancer drug, 5-fluorouracil; proteases, such as serratia protease, thermolysin, subtilisin, carboxypeptidases and cathepsins (such as cathepsins B and L), that are useful for converting peptide-containing prodrugs into free drugs; D-alanylcarboxypeptidases, useful for converting prodrugs that contain D-amino acid substituents; carbohydrate-cleaving enzymes such as β-galactosidase and neuraminidase useful for converting glycosylated prodrugs into free drugs; β-lactamase useful for converting drugs derivatized with β-lactams into free drugs; and penicillin amidases, such as penicillin V amidase or penicillin G amidase, useful for converting drugs derivatized at their amine nitrogens with phenoxyacetyl or phenylacetyl groups, respectively, into free drugs. Alternatively, antibodies with enzymatic activity, also known in the art as “abzymes”, can be used to convert the prodrugs of the invention into free active drugs (see, e.g., Massey, Nature 328:457-458 (1987)). Antibody-abzyme conjugates can be prepared as described herein for delivery of the abzyme to a tumor cell population.
The enzymes of this invention can be covalently bound to the anti-TAHO antibodies by techniques well known in the art such as the use of the heterobifunctional crosslinking reagents discussed above. Alternatively, fusion proteins comprising at least the antigen binding region of an antibody of the invention linked to at least a functionally active portion of an enzyme of the invention can be constructed using recombinant DNA techniques well known in the art (see, e.g., Neuberger et al., Nature 312:604-608 (1984).
F. Full-Length TAHO Polypeptides
The present invention also provides newly identified and isolated nucleotide sequences encoding polypeptides referred to in the present application as TAHO polypeptides. In particular, cDNAs (partial and full-length) encoding various TAHO polypeptides have been identified and isolated, as disclosed in further detail in the Examples below.
As disclosed in the Examples below, various cDNA clones have been deposited with the ATCC. The actual nucleotide sequences of those clones can readily be determined by the skilled artisan by sequencing of the deposited clone using routine methods in the art. The predicted amino acid sequence can be determined from the nucleotide sequence using roufine skill. For the TAHO polypeptides and encoding nucleic acids described herein, in some cases, Applicants have identified what is believed to be the reading frame best identifiable with the sequence information available at the time.
G. Anti-TAHO Antibody and TAHO Polypeptide Variants
In addition to the anti-TAHO antibodies and full-length native sequence TAHO polypeptides described herein, it is contemplated that anti-TAHO antibody and TAHO polypeptide variants can be prepared. Anti-TAHO antibody and TAHO polypeptide variants can be prepared by introducing appropriate nucleotide changes into the encoding DNA, and/or by synthesis of the desired antibody or polypeptide. Those skilled in the art will appreciate that amino acid changes may alter post-translational processes of the anti-TAHO antibody or TAHO polypeptide, such as changing the number or position of glycosylation sites or altering the membrane anchoring characteristics.
Variations in the anti-TAHO antibodies and TAHO polypeptides described herein, can be made, for example, using any of the techniques and guidelines for conservative and non-conservative mutations set forth, for instance, in U.S. Pat. No. 5,364,934. Variations may be a substitution, deletion or insertion of one or more codons encoding the antibody or polypeptide that results in a change in the amino acid sequence as compared with the native sequence antibody or polypeptide. Optionally the variation is by substitution of at least one amino acid with any other amino acid in one or more of the domains of the anti-TAHO antibody or TAHO polypeptide. Guidance in determining which amino acid residue may be inserted, substituted or deleted without adversely affecting the desired activity may be found by comparing the sequence of the anti-TAHO antibody or TAHO polypeptide with that of homologous known protein molecules and minimizing the number of amino acid sequence changes made in regions of high homology. Amino acid substitutions can be the result of replacing one amino acid with another amino acid having similar structural and/or chemical properties, such as the replacement of a leucine with a serine, i.e., conservative amino acid replacements. Insertions or deletions may optionally be in the range of about 1 to 5 amino acids. The variation allowed may be determined by systematically making insertions, deletions or substitutions of amino acids in the sequence and testing the resulting variants for activity exhibited by the full-length or mature native sequence.
Anti-TAHO antibody and TAHO polypeptide fragments are provided herein. Such fragments may be truncated at the N-terminus or C-terminus, or may lack internal residues, for example, when compared with a full length native antibody or protein. Certain fragments lack amino acid residues that are not essential for a desired biological activity of the anti-TAHO antibody or TAHO polypeptide.
Anti-TAHO antibody and TAHO polypeptide fragments may be prepared by any of a number of conventional techniques. Desired peptide fragments may be chemically synthesized. An alternative approach involves generating antibody or polypeptide fragments by enzymatic digestion, e.g., by treating the protein with an enzyme known to cleave proteins at sites defined by particular amino acid residues, or by digesting the DNA with suitable restriction enzymes and isolating the desired fragment. Yet another suitable technique involves isolating and amplifying a DNA fragment encoding a desired antibody or polypeptide fragment, by polymerase chain reaction (PCR). Oligonucleotides that define the desired termini of the DNA fragment are employed at the 5′ and 3′ primers in the PCR. Preferably, anti-TAHO antibody and TAHO polypeptide fragments share at least one biological and/or immunological activity with the native anti-TAHO antibody or TAHO polypeptide disclosed herein.
In particular embodiments, conservative substitutions of interest are shown in Table 10 under the heading of preferred substitutions. If such substitutions result in a change in biological activity, then more substantial changes, denominated exemplary substitutions in Table 6, or as further described below in reference to amino acid classes, are introduced and the products screened.
Substantial modifications in function or immunological identity of the anti-TAHO antibody or TAHO polypeptide are accomplished by selecting substitutions that differ significantly in their effect on maintaining (a) the structure of the polypeptide backbone in the area of the substitution, for example, as a sheet or helical conformation, (b) the charge or hydrophobicity of the molecule at the target site, or (c) the bulk of the side chain. Naturally occurring residues are divided into groups based on common side-chain properties:
(1) hydrophobic: norleucine, met, ala, val, leu, ile;
(2) neutral hydrophilic: cys, ser, thr;
(3) acidic: asp, glu;
(4) basic: asn, gln, his, lys, arg;
(5) residues that influence chain orientation: gly, pro; and
(6) aromatic: trp, tyr, phe.
Non-conservative substitutions will entail exchanging a member of one of these classes for another class. Such substituted residues also may be introduced into the conservative substitution sites or, more preferably, into the remaining (non-conserved) sites.
The variations can be made using methods known in the art such as oligonucleotide-mediated (site-directed) mutagenesis, alanine scanning, and PCR mutagenesis. Site-directed mutagenesis [Carter et al., Nucl. Acids Res., 13:4331 (1986); Zoller et al., Nucl. Acids Res., 10:6487 (1987)], cassette mutagenesis [Wells et al., Gene, 34:315 (1985)], restriction selection mutagenesis [Wells et al., Philos. Trans. R. Soc. London SerA, 317:415 (1986)] or other known techniques can be performed on the cloned DNA to produce the anti-TAHO antibody or TAHO polypeptide variant DNA.
Scanning amino acid analysis can also be employed to identify one or more amino acids along a contiguous sequence. Among the preferred scanning amino acids are relatively small, neutral amino acids. Such amino acids include alanine, glycine, serine, and cysteine. Alanine is typically a preferred scanning amino acid among this group because it eliminates the side-chain beyond the beta-carbon and is less likely to alter the main-chain conformation of the variant [Cunningham and Wells, Science, 244:1081-1085 (1989)]. Alanine is also typically preferred because it is the most common amino acid. Further, it is frequently found in both buried and exposed positions [Creighton, The Proteins, (W.H. Freeman & Co., N.Y.); Chothia, J. Mol. Biol., 150:1 (1976)]. If alanine substitution does not yield adequate amounts of variant, an isoteric amino acid can be used.
Any cysteine residue not involved in maintaining the proper conformation of the anti-TAHO antibody or TAHO polypeptide also may be substituted, generally with serine, to improve the oxidative stability of the molecule and prevent aberrant crosslinking. Conversely, cysteine bond(s) may be added to the anti-TAHO antibody or TAHO polypeptide to improve its stability (particularly where the antibody is an antibody fragment such as an Fv fragment).
A particularly preferred type of substitutional variant involves substituting one or more hypervariable region residues of a parent antibody (e.g., a humanized or human antibody). Generally, the resulting variant(s) selected for further development will have improved biological properties relative to the parent antibody from which they are generated. A convenient way for generating such substitutional variants involves affinity maturation using phage display. Briefly, several hypervariable region sites (e.g., 6-7 sites) are mutated to generate all possible amino substitutions at each site. The antibody variants thus generated are displayed in a monovalent fashion from filamentous phage particles as fusions to the gene III product of M13 packaged within each particle. The phage-displayed variants are then screened for their biological activity (e.g., binding affinity) as herein disclosed. In order to identify candidate hypervariable region sites for modification, alanine scanning mutagenesis can be performed to identify hypervariable region residues contributing significantly to antigen binding. Alternatively, or additionally, it may be beneficial to analyze a crystal structure of the antigen-antibody complex to identify contact points between the antibody and human TAHO polypeptide. Such contact residues and neighboring residues are candidates for substitution according to the techniques elaborated herein. Once such variants are generated, the panel of variants is subjected to screening as described herein and antibodies with superior properties in one or more relevant assays may be selected for further development.
Nucleic acid molecules encoding amino acid sequence variants of the anti-TAHO antibody are prepared by a variety of methods known in the art. These methods include, but are not limited to, isolation from a natural source (in the case of naturally occurring amino acid sequence variants) or preparation by oligonucleotide-mediated (or site-directed) mutagenesis, PCR mutagenesis, and cassette mutagenesis of an earlier prepared variant or a non-variant version of the anti-TAHO antibody.
H. Modifications of Anti-TAHO Antibodies and TAHO Polypeptides
Covalent modifications of anti-TAHO antibodies and TAHO polypeptides are included within the scope of this invention. One type of covalent modification includes reacting targeted amino acid residues of an anti-TAHO antibody or TAHO polypeptide with an organic derivatizing agent that is capable of reacting with selected side chains or the N- or C-terminal residues of the anti-TAHO antibody or TAHO polypeptide. Derivatization with bifunctional agents is useful, for instance, for crosslinking anti-TAHO antibody or TAHO polypeptide to a water-insoluble support matrix or surface for use in the method for purifying anti-TAHO antibodies, and vice-versa. Commonly used crosslinking agents include, e.g., 1,1-bis(diazoacetyl)-2-phenylethane, glutaraldehyde, N-hydroxysuccinimide esters, for example, esters with 4-azidosalicylic acid, homobifunctional imidoesters, including disuccinimidyl esters such as 3,3′-dithiobis(succinimidylpropionate), bifunctional maleimides such as bis-N-maleimido-1,8-octane and agents such as methyl-3-[(p-azidophenyl)dithio]propioimidate.
Other modifications include deamidation of glutaminyl and asparaginyl residues to the corresponding glutamyl and aspartyl residues, respectively, hydroxylation of proline and lysine, phosphorylation of hydroxyl groups of seryl or threonyl residues, methylation of the α-amino groups of lysine, arginine, and histidine side chains [T. E. Creighton, Proteins: Structure and Molecular Properties, W.H. Freeman & Co., San Francisco, pp. 79-86 (1983)], acetylation of the N-terminal amine, and amidation of any C-terminal carboxyl group.
Another type of covalent modification of the anti-TAHO antibody or TAHO polypeptide included within the scope of this invention comprises altering the native glycosylation pattern of the antibody or polypeptide. “Altering the native glycosylation pattern” is intended for purposes herein to mean deleting one or more carbohydrate moieties found in native sequence anti-TAHO antibody or TAHO polypeptide (either by removing the underlying glycosylation site or by deleting the glycosylation by chemical and/or enzymatic means), and/or adding one or more glycosylation sites that are not present in the native sequence anti-TAHO antibody or TAHO polypeptide. In addition, the phrase includes qualitative changes in the glycosylation of the native proteins, involving a change in the nature and proportions of the various carbohydrate moieties present.
Glycosylation of antibodies and other polypeptides is typically either N-linked or O-linked. N-linked refers to the attachment of the carbohydrate moiety to the side chain of an asparagine residue. The tripeptide sequences asparagine-X-serine and asparagine-X-threonine, where X is any amino acid except proline, are the recognition sequences for enzymatic attachment of the carbohydrate moiety to the asparagine side chain. Thus, the presence of either of these tripeptide sequences in a polypeptide creates a potential glycosylation site. O-linked glycosylation refers to the attachment of one of the sugars N-aceylgalactosamine, galactose, or xylose to a hydroxyamino acid, most commonly serine or threonine, although 5-hydroxyproline or 5-hydroxylysine may also be used.
Addition of glycosylation sites to the anti-TAHO antibody or TAHO polypeptide is conveniently accomplished by altering the amino acid sequence such that it contains one or more of the above-described tripeptide sequences (for N-linked glycosylation sites). The alteration may also be made by the addition of, or substitution by, one or more serine or threonine residues to the sequence of the original anti-TAHO antibody or TAHO polypeptide (for O-linked glycosylation sites). The anti-TAHO antibody or TAHO polypeptide amino acid sequence may optionally be altered through changes at the DNA level, particularly by mutating the DNA encoding the anti-TAHO antibody or TAHO polypeptide at preselected bases such that codons are generated that will translate into the desired amino acids.
Another means of increasing the number of carbohydrate moieties on the anti-TAHO antibody or TAHO polypeptide is by chemical or enzymatic coupling of glycosides to the polypeptide. Such methods are described in the art, e.g., in WO 87/05330 published 11 Sep. 1987, and in Aplin and Wriston, CRC Crit. Rev. Biochem., pp. 259-306 (1981).
Removal of carbohydrate moieties present on the anti-TAHO antibody or TAHO polypeptide may be accomplished chemically or enzymatically or by mutational substitution of codons encoding for amino acid residues that serve as targets for glycosylation. Chemical deglycosylation techniques are known in the art and described, for instance, by Hakimuddin, et al., Arch. Biochem. Biophys., 259:52 (1987) and by Edge et al., Anal. Biochem., 118:131 (1981). Enzymatic cleavage of carbohydrate moieties on polypeptides can be achieved by the use of a variety of endo- and exo-glycosidases as described by Thotakura et al., Meth. Enzymol., 138:350 (1987).
Another type of covalent modification of anti-TAHO antibody or TAHO polypeptide comprises linking the antibody or polypeptide to one of a variety of nonproteinaceous polymers, e.g., polyethylene glycol (PEG), polypropylene glycol, or polyoxyalkylenes, in the manner set forth in U.S. Pat. Nos. 4,640,835; 4,496,689; 4,301,144; 4,670,417; 4,791,192 or 4,179,337. The antibody or polypeptide also may be entrapped in microcapsules prepared, for example, by coacervation techniques or by interfacial polymerization (for example, hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethacylate) microcapsules, respectively), in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules), or in macroemulsions. Such techniques are disclosed in Remington's Pharmaceutical Sciences, 16th edition, Oslo, A., Ed., (1980).
The anti-TAHO antibody or TAHO polypeptide of the present invention may also be modified in a way to form chimeric molecules comprising an anti-TAHO antibody or TAHO polypeptide fused to another, heterologous polypeptide or amino acid sequence.
In one embodiment, such a chimeric molecule comprises a fusion of the anti-TAHO antibody or TAHO polypeptide with a tag polypeptide which provides an epitope to which an anti-tag antibody can selectively bind. The epitope tag is generally placed at the amino- or carboxyl-terminus of the anti-TAHO antibody or TAHO polypeptide. The presence of such epitope-tagged forms of the anti-TAHO antibody or TAHO polypeptide can be detected using an antibody against the tag polypeptide. Also, provision of the epitope tag enables the anti-TAHO antibody or TAHO polypeptide to be readily purified by affinity purification using an anti-tag antibody or another type of affinity matrix that binds to the epitope tag. Various tag polypeptides and their respective antibodies are well known in the art. Examples include poly-histidine (poly-his) or poly-histidine-glycine (poly-his-gly) tags; the flu HA tag polypeptide and its antibody 12CA5 [Field et al., Mol. Cell. Biol., 8:2159-2165 (1988)]; the c-myc tag and the 8F9, 3C7, 6E10, G4, B7 and 9E10 antibodies thereto [Evan et al., Molecular and Cellular Biology, 5:3610-3616 (1985)]; and the Herpes Simplex virus glycoprotein D (gD) tag and its antibody [Paborsky et al., Protein Engineering, 3(6):547-553 (1990)]. Other tag polypeptides include the Flag-peptide [Hopp et al., BioTechnology, 6:1204-1210 (1988)]; the KT3 epitope peptide [Martin et al., Science, 255:192-194 (1992)]; an α-tubulin epitope peptide [Skinner et al., J. Biol. Chem., 266:15163-15166 (1991)]; and the T7 gene 10 protein peptide tag [Lutz-Freyermuth et al., Proc. Natl. Acad. Sci. USA, 87:6393-6397 (1990)].
In an alternative embodiment, the chimeric molecule may comprise a fusion of the anti-TAHO antibody or TAHO polypeptide with an immunoglobulin or a particular region of an immunoglobulin. For a bivalent form of the chimeric molecule (also referred to as an “immunoadhesin”), such a fusion could be to the Fc region of an IgG molecule. The Ig fusions preferably include the substitution of a soluble (transmembrane domain deleted or inactivated) form of an anti-TAHO antibody or TAHO polypeptide in place of at least one variable region within an Ig molecule. In a particularly preferred embodiment, the immunoglobulin fusion includes the hinge, CH2 and CH3, or the hinge, CH1, CH2 and CH3 regions of an IgG1 molecule. For the production of immunoglobulin fusions see also U.S. Pat. No. 5,428,130 issued Jun. 27, 1995.
I. Preparation of Anti-TAHO Antibodies and TAHO Polypeptides
The description below relates primarily to production of anti-TAHO antibodies and TAHO polypeptides by culturing cells transformed or transfected with a vector containing anti-TAHO antibody- and TAHO polypeptide-encoding nucleic acid. It is, of course, contemplated that alternative methods, which are well known in the art, may be employed to prepare anti-TAHO antibodies and TAHO polypeptides. For instance, the appropriate amino acid sequence, or portions thereof, may be produced by direct peptide synthesis using solid-phase techniques [see, e.g., Stewart et al., Solid-Phase Peptide Synthesis, W.H. Freeman Co., San Francisco, Calif. (1969); Merrifield, J. Am. Chem. Soc., 85:2149-2154 (1963)]. In vitro protein synthesis may be performed using manual techniques or by automation. Automated synthesis may be accomplished, for instance, using an Applied Biosystems Peptide Synthesizer (Foster City, Calif.) using manufacturer's instructions. Various portions of the anti-TAHO antibody or TAHO polypeptide may be chemically synthesized separately and combined using chemical or enzymatic methods to produce the desired anti-TAHO antibody or TAHO polypeptide.
1. Isolation of DNA Encoding Anti-TAHO Antibody or TAHO Polypeptide
DNA encoding anti-TAHO antibody or TAHO polypeptide may be obtained from a cDNA library prepared from tissue believed to possess the anti-TAHO antibody or TAHO polypeptide mRNA and to express it at a detectable level. Accordingly, human anti-TAHO antibody or TAHO polypeptide DNA can be conveniently obtained from a cDNA library prepared from human tissue. The anti-TAHO antibody- or TAHO polypeptide-encoding gene may also be obtained from a genomic library or by known synthetic procedures (e.g., automated nucleic acid synthesis).
Libraries can be screened with probes (such as oligonucleotides of at least about 20-80 bases) designed to identify the gene of interest or the protein encoded by it. Screening the cDNA or genomic library with the selected probe may be conducted using standard procedures, such as described in Sambrook et al., Molecular Cloning: A Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1989). An alternative means to isolate the gene encoding anti-TAHO antibody or TAHO polypeptide is to use PCR methodology [Sambrook et al., supra; Dieffenbach et al., PCR Primer: A Laboratory Manual (Cold Spring Harbor Laboratory Press, 1995)].
Techniques for screening a cDNA library are well known in the art. The oligonucleotide sequences selected as probes should be of sufficient length and sufficiently unambiguous that false positives are minimized. The oligonucleotide is preferably labeled such that it can be detected upon hybridization to DNA in the library being screened. Methods of labeling are well known in the art, and include the use of radiolabels like 32P-labeled ATP, biotinylation or enzyme labeling. Hybridization conditions, including moderate stringency and high stringency, are provided in Sambrook et al., supra.
Sequences identified in such library screening methods can be compared and aligned to other known sequences deposited and available in public databases such as GenBank or other private sequence databases. Sequence identity (at either the amino acid or nucleotide level) within defined regions of the molecule or across the full-length sequence can be determined using methods known in the art and as described herein.
Nucleic acid having protein coding sequence may be obtained by screening selected cDNA or genomic libraries using the deduced amino acid sequence disclosed herein for the first time, and, if necessary, using conventional primer extension procedures as described in Sambrook et al., supra, to detect precursors and processing intermediates of mRNA that may not have been reverse-transcribed into cDNA.
2. Selection and Transformation of Host Cells
Host cells are transfected or transformed with expression or cloning vectors described herein for anti-TAHO antibody or TAHO polypeptide production and cultured in conventional nutrient media modified as appropriate for inducing promoters, selecting transformants, or amplifying the genes encoding the desired sequences. The culture conditions, such as media, temperature, pH and the like, can be selected by the skilled artisan without undue experimentation. In general, principles, protocols, and practical techniques for maximizing the productivity of cell cultures can be found in Mammalian Cell Biotechnology: a Practical Approach, M. Butler, ed. (IRL Press, 1991) and Sambrook et al., supra.
Methods of eukaryotic cell transfection and prokaryotic cell transformation are known to the ordinarily skilled artisan, for example, CaCl2, CaPO4, liposome-mediated and electroporation. Depending on the host cell used, transformation is performed using standard techniques appropriate to such cells. The calcium treatment employing calcium chloride, as described in Sambrook et al., supra, or electroporation is generally used for prokaryotes. Infection with Agrobacterium tumefaciens is used for transformation of certain plant cells, as described by Shaw et al., Gene, 23:315 (1983) and WO 89/05859 published 29 Jun. 1989. For mammalian cells without such cell walls, the calcium phosphate precipitation method of Graham and van der Eb, Virology, 52:456-457 (1978) can be employed. General aspects of mammalian cell host system transfections have been described in U.S. Pat. No. 4,399,216. Transformations into yeast are typically carried out according to the method of Van Solingen et al., J. Bact., 130:946 (1977) and Hsiao et al., Proc. Natl. Acad. Sci. (USA), 76:3829 (1979). However, other methods for introducing DNA into cells, such as by nuclear microinjection, electroporation, bacterial protoplast fusion with intact cells, or polycations, e.g., polybrene, polyornithine, may also be used. For various techniques for transforming mammalian cells, see Keown et al., Methods in Enzymology, 185:527-537 (1990) and Mansour et al., Nature, 336:348-352 (1988).
Suitable host cells for cloning or expressing the DNA in the vectors herein include prokaryote, yeast, or higher eukaryote cells. Suitable prokaryotes include but are not limited to eubacteria, such as Gram-negative or Gram-positive organisms, for example, Enterobacteriaceae such as E. coli. Various E. coli strains are publicly available, such as E. coli K12 strain MM294 (ATCC 31,446); E. coli X1776 (ATCC 31,537); E. coli strain W3110 (ATCC 27,325) and K5 772 (ATCC 53,635). Other suitable prokaryotic host cells include Enterobacteriaceae such as Escherichia, e.g., E. coli, Enterobacter, Erwinia, Klebsiella, Proteus, Salmonella, e.g., Salmonella typhimurium, Serratia, e.g., Serratia marcescans, and Shigella, as well as Bacilli such as B. subtilis and B. licheniformis (e.g., B. licheniformis 41P disclosed in DD 266,710 published 12 Apr. 1989), Pseudomonas such as P. aeruginosa, and Streptomyces. These examples are illustrative rather than limiting. Strain W3110 is one particularly preferred host or parent host because it is a common host strain for recombinant DNA product fermentations. Preferably, the host cell secretes minimal amounts of proteolytic enzymes. For example, strain W3110 may be modified to effect a genetic mutation in the genes encoding proteins endogenous to the host, with examples of such hosts including E. coli W3110 strain 1A2, which has the complete genotype tonA; E. coli W3110 strain 9E4, which has the complete genotype tonA ptr3; E. coli W3110 strain 27C7 (ATCC 55,244), which has the complete genotype tonA ptr3 phoA E15 (argF-lac)169 degP ompT kanr; E. coli W3110 strain 37D6, which has the complete genotype tonA ptr3 phoA E15 (argF-lac)169 degP ompT rbs7 ilvG kanr; E. coli W3110 strain 40B4, which is strain 37D6 with a non-kanamycin resistant degP deletion mutation; and an E. coli strain having mutant periplasmic protease disclosed in U.S. Pat. No. 4,946,783 issued 7 Aug. 1990. Alternatively, in vitro methods of cloning, e.g., PCR or other nucleic acid polymerase reactions, are suitable.
Full length antibody, antibody fragments, and antibody fusion proteins can be produced in bacteria, in particular when glycosylation and Fc effector function are not needed, such as when the therapeutic antibody is conjugated to a cytotoxic agent (e.g., a toxin) and the immunoconjugate by itself shows effectiveness in tumor cell destruction. Full length antibodies have greater half life in circulation. Production in E. coli is faster and more cost efficient. For expression of antibody fragments and polypeptides in bacteria, see, e.g., U.S. Pat. No. 5,648,237 (Carter et. al.), U.S. Pat. No. 5,789,199 (Joly et al.), and U.S. Pat. No. 5,840,523 (Simmons et al.) which describes translation initiation regio (TIR) and signal sequences for optimizing expression and secretion, these patents incorporated herein by reference. After expression, the antibody is isolated from the E. coli cell paste in a soluble fraction and can be purified through, e.g., a protein A or G column depending on the isotype. Final purification can be carried out similar to the process for purifying antibody expressed e.g., in CHO cells.
In addition to prokaryotes, eukaryotic microbes such as filamentous fungi or yeast are suitable cloning or expression hosts for anti-TAHO antibody- or TAHO polypeptide-encoding vectors. Saccharomyces cerevisiae is a commonly used lower eukaryotic host microorganism. Others include Schizosaccharomyces pombe (Beach and Nurse, Nature, 290: 140 [1981]; EP 139,383 published 2 May 1985); Kluyveromyces hosts (U.S. Pat. No. 4,943,529; Fleer et al., Bio/Technology, 9:968-975 (1991)) such as, e.g., K. lactis (MW98-8C, CBS683, CBS4574; Louvencourt et al., J. Bacteriol., 154(2):737-742 [1983]), K. fragilis (ATCC 12,424), K. bulgaricus (ATCC 16,045), K. wickeramii (ATCC 24,178), K. waltii (ATCC 56,500), K. drosophilarum (ATCC 36,906; Van den Berg et al., Bio/Technology, 8:135 (1990)), K. thermotolerans, and K. marxianus; yarrowia (EP 402,226); Pichia pastoris (EP 183,070; Sreekrishna et al., J. Basic Microbiol., 28:265-278 [1988]); Candida; Trichoderma reesia (EP 244,234); Neurospora crassa (Case et al., Proc. Natl. Acad. Sci. USA, 76:5259-5263 [1979]); Schwanniomyces such as Schwanniomyces occidentalis (EP 394,538 published 31 Oct. 1990); and filamentous fungi such as, e.g., Neurospora, Penicillium, Tolypocladium (WO 91/00357 published 10 Jan. 1991), and Aspergillus hosts such as A. nidulans (Ballance et al., Biochem. Biophys. Res. Commun., 112:284-289 [1983]; Tilburn et al., Gene, 26:205-221 [1983]; Yelton et al., Proc. Natl. Acad. Sci. USA, 81: 1470-1474 [1984]) and A. niger (Kelly and Hynes, EMBO J., 4:475-479 [1985]). Methylotropic yeasts are suitable herein and include, but are not limited to, yeast capable of growth on methanol selected from the genera consisting of Hansenula, Candida, Kloeckera, Pichia, Saccharomyces, Torulopsis, and Rhodotorula. A list of specific species that are exemplary of this class of yeasts may be found in C. Anthony, The Biochemistry of Methylotrophs, 269 (1982).
Suitable host cells for the expression of glycosylated anti-TAHO antibody or TAHO polypeptide are derived from multicellular organisms. Examples of invertebrate cells include insect cells such as Drosophila S2 and Spodoptera Sf9, as well as plant cells, such as cell cultures of cotton, corn, potato, soybean, petunia, tomato, and tobacco. Numerous baculoviral strains and variants and corresponding permissive insect host cells from hosts such as Spodoptera frugiperda (caterpillar), Aedes aegypti (mosquito), Aedes albopictus (mosquito), Drosophila melanogaster (fruitfly), and Bombyx mori have been identified. A variety of viral strains for transfection are publicly available, e.g., the L-1 variant of Autographa californica NPV and the Bm-5 strain of Bombyx mori NPV, and such viruses may be used as the virus herein according to the present invention, particularly for transfection of Spodoptera frugiperda cells.
However, interest has been greatest in vertebrate cells, and propagation of vertebrate cells in culture (tissue culture) has become a routine procedure. Examples of useful mammalian host cell lines are monkey kidney CV1 line transformed by SV40 (COS-7, ATCC CRL 1651); human embryonic kidney line (293 or 293 cells subcloned for growth in suspension culture, Graham et al., J. Gen Virol. 36:59 (1977)); baby hamster kidney cells (BHK, ATCC CCL 10); Chinese hamster ovary cells/−DHFR (CHO, Urlaub et al., Proc. Natl. Acad. Sci. USA 77:4216 (1980)); mouse sertoli cells (TM4, Mather, Biol. Reprod. 23:243-251 (1980)); monkey kidney cells (CV1 ATCC CCL 70); African green monkey kidney cells (VERO-76, ATCC CRL-1587); human cervical carcinoma cells (HELA, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34); buffalo rat liver cells (BRL 3A, ATCC CRL 1442); human lung cells (W138, ATCC CCL 75); human liver cells (Hep G2, HB 8065); mouse mammary tumor (MMT 060562, ATCC CCL51); TRI cells (Mather et al., Annals N.Y. Acad. Sci. 383:44-68 (1982)); MRC 5 cells; FS4 cells; and a human hepatoma line (Hep G2).
Host cells are transformed with the above-described expression or cloning vectors for anti-TAHO antibody or TAHO polypeptide production and cultured in conventional nutrient media modified as appropriate for inducing promoters, selecting transformants, or amplifying the genes encoding the desired sequences.
3. Selection and Use of a Replicable Vector
The nucleic acid (e.g., cDNA or genomic DNA) encoding anti-TAHO antibody or TAHO polypeptide may be inserted into a replicable vector for cloning (amplification of the DNA) or for expression. Various vectors are publicly available. The vector may, for example, be in the form of a plasmid, cosmid, viral particle, or phage. The appropriate nucleic acid sequence may be inserted into the vector by a variety of procedures. In general, DNA is inserted into an appropriate restriction endonuclease site(s) using techniques known in the art. Vector components generally include, but are not limited to, one or more of a signal sequence, an origin of replication, one or more marker genes, an enhancer element, a promoter, and a transcription termination sequence. Construction of suitable vectors containing one or more of these components employs standard ligation techniques which are known to the skilled artisan.
The TAHO may be produced recombinantly not only directly, but also as a fusion polypeptide with a heterologous polypeptide, which may be a signal sequence or other polypeptide having a specific cleavage site at the N-terminus of the mature protein or polypeptide. In general, the signal sequence may be a component of the vector, or it may be a part of the anti-TAHO antibody- or TAHO polypeptide-encoding DNA that is inserted into the vector. The signal sequence may be a prokaryotic signal sequence selected, for example, from the group of the alkaline phosphatase, penicillinase, lpp, or heat-stable enterotoxin II leaders. For yeast secretion the signal sequence may be, e.g., the yeast invertase leader, alpha factor leader (including Saccharomyces and Kluyveromyces α-factor leaders, the latter described in U.S. Pat. No. 5,010,182), or acid phosphatase leader, the C. albicans glucoamylase leader (EP 362,179 published 4 Apr. 1990), or the signal described in WO 90/13646 published 15 Nov. 1990. In mammalian cell expression, mammalian signal sequences may be used to direct secretion of the protein, such as signal sequences from secreted polypeptides of the same or related species, as well as viral secretory leaders.
Both expression and cloning vectors contain a nucleic acid sequence that enables the vector to replicate in one or more selected host cells. Such sequences are well known for a variety of bacteria, yeast, and viruses. The origin of replication from the plasmid pBR322 is suitable for most Gram-negative bacteria, the 2μ plasmid origin is suitable for yeast, and various viral origins (SV40, polyoma, adenovirus, VSV or BPV) are useful for cloning vectors in mammalian cells.
Expression and cloning vectors will typically contain a selection gene, also termed a selectable marker. Typical selection genes encode proteins that (a) confer resistance to antibiotics or other toxins, e.g., ampicillin, neomycin, methotrexate, or tetracycline, (b) complement auxotrophic deficiencies, or (c) supply critical nutrients not available from complex media, e.g., the gene encoding D-alanine racemase for Bacilli.
An example of suitable selectable markers for mammalian cells are those that enable the identification of cells competent to take up the anti-TAHO antibody- or TAHO polypeptide-encoding nucleic acid, such as DHFR or thymidine kinase. An appropriate host cell when wild-type DHFR is employed is the CHO cell line deficient in DHFR activity, prepared and propagated as described by Urlaub et al., Proc. Natl. Acad. Sci. USA, 77:4216 (1980). A suitable selection gene for use in yeast is the trp1 gene present in the yeast plasmid YRp7 [Stinchcomb et al., Nature, 282:39 (1979); Kingsman et al., Gene, 7:141 (1979); Tschemper et al., Gene, 10:157 (1980)]. The trp1 gene provides a selection marker for a mutant strain of yeast lacking the ability to grow in tryptophan, for example, ATCC No. 44076 or PEP4-1 [Jones, Genetics, 85:12 (1977)].
Expression and cloning vectors usually contain a promoter operably linked to the anti-TAHO antibody- or TAHO polypeptide-encoding nucleic acid sequence to direct mRNA synthesis. Promoters recognized by a variety of potential host cells are well known. Promoters suitable for use with prokaryotic hosts include the β-lactamase and lactose promoter systems [Chang et al., Nature, 275:615 (1978); Goeddel et al., Nature, 281:544 (1979)], alkaline phosphatase, a tryptophan (trp) promoter system [Goeddel, Nucleic Acids Res., 8:4057 (1980); EP 36,776], and hybrid promoters such as the tac promoter [deBoer et al., Proc. Natl. Acad. Sci. USA, 80:21-25 (1983)]. Promoters for use in bacterial systems also will contain a Shine-Dalgarno (S.D.) sequence operably linked to the DNA encoding anti-TAHO antibody or TAHO polypeptide.
Examples of suitable promoting sequences for use with yeast hosts include the promoters for 3-phosphoglycerate kinase [Hitzeman et al., J. Biol. Chem., 255:2073 (1980)] or other glycolytic enzymes [Hess et al., J. Adv. Enzyme Reg., 7:149 (1968); Holland, Biochemistry, 17:4900 (1978)], such as enolase, glyceraldehyde-3-phosphate dehydrogenase, hexokinase, pyruvate decarboxylase, phosphofructokinase, glucose-6-phosphate isomerase, 3-phosphoglycerate mutase, pyruvate kinase, triosephosphate isomerase, phosphoglucose isomerase, and glucokinase.
Other yeast promoters, which are inducible promoters having the additional advantage of transcription controlled by growth conditions, are the promoter regions for alcohol dehydrogenase 2, isocytochrome C, acid phosphatase, degradative enzymes associated with nitrogen metabolism, metallothionein, glyceraldehyde-3-phosphate dehydrogenase, and enzymes responsible for maltose and galactose utilization. Suitable vectors and promoters for use in yeast expression are further described in EP 73,657.
Anti-TAHO antibody or TAHO polypeptide transcription from vectors in mammalian host cells is controlled, for example, by promoters obtained from the genomes of viruses such as polyoma virus, fowlpox virus (UK 2,211,504 published 5 Jul. 1989), adenovirus (such as Adenovirus 2), bovine papilloma virus, avian sarcoma virus, cytomegalovirus, a retrovirus, hepatitis-B virus and Simian Virus 40 (SV40), from heterologous mammalian promoters, e.g., the actin promoter or an immunoglobulin promoter, and from heat-shock promoters, provided such promoters are compatible with the host cell systems.
Transcription of a DNA encoding the anti-TAHO antibody or TAHO polypeptide by higher eukaryotes may be increased by inserting an enhancer sequence into the vector. Enhancers are cis-acting elements of DNA, usually about from 10 to 300 bp, that act on a promoter to increase its transcription. Many enhancer sequences are now known from mammalian genes (globin, elastase, albumin, α-fetoprotein, and insulin). Typically, however, one will use an enhancer from a eukaryotic cell virus. Examples include the SV40 enhancer on the late side of the replication origin (bp 100-270), the cytomegalovirus early promoter enhancer, the polyoma enhancer on the late side of the replication origin, and adenovirus enhancers. The enhancer may be spliced into the vector at a position 5′ or 3′ to the anti-TAHO antibody or TAHO polypeptide coding sequence, but is preferably located at a site 5′ from the promoter.
Expression vectors used in eukaryotic host cells (yeast, fungi, insect, plant, animal, human, or nucleated cells from other multicellular organisms) will also contain sequences necessary for the termination of transcription and for stabilizing the mRNA. Such sequences are commonly available from the 5′ and, occasionally 3′, untranslated regions of eukaryotic or viral DNAs or cDNAs. These regions contain nucleotide segments transcribed as polyadenylated fragments in the untranslated portion of the mRNA encoding anti-TAHO antibody or TAHO polypeptide.
Still other methods, vectors, and host cells suitable for adaptation to the synthesis of anti-TAHO antibody or TAHO polypeptide in recombinant vertebrate cell culture are described in Gething et al., Nature, 293:620-625 (1981); Mantei et al., Nature, 281:40-46 (1979); EP 117,060; and EP 117,058.
4. Culturing the Host Cells
The host cells used to produce the anti-TAHO antibody or TAHO polypeptide of this invention may be cultured in a variety of media. Commercially available media such as Ham's F10 (Sigma), Minimal Essential Medium ((MEM), (Sigma), RPMI-1640 (Sigma), and Dulbecco's Modified Eagle's Medium ((DMEM), Sigma) are suitable for culturing the host cells. In addition, any of the media described in Ham et al., Meth. Enz. 58:44 (1979), Barnes et al., Anal. Biochem. 102:255 (1980), U.S. Pat. Nos. 4,767,704; 4,657,866; 4,927,762; 4,560,655; or 5,122,469; WO 90/03430; WO 87/00195; or U.S. Pat. Re. 30,985 may be used as culture media for the host cells. Any of these media may be supplemented as necessary with hormones and/or other growth factors (such as insulin, transferrin, or epidermal growth factor), salts (such as sodium chloride, calcium, magnesium, and phosphate), buffers (such as HEPES), nucleotides (such as adenosine and thymidine), antibiotics (such as GENTAMYCIN™ drug), trace elements (defined as inorganic compounds usually present at final concentrations in the micromolar range), and glucose or an equivalent energy source. Any other necessary supplements may also be included at appropriate concentrations that would be known to those skilled in the art. The culture conditions, such as temperature, pH, and the like, are those previously used with the host cell selected for expression, and will be apparent to the ordinarily skilled artisan.
5. Detecting Gene Amplification/Expression
Gene amplification and/or expression may be measured in a sample directly, for example, by conventional Southern blotting, Northern blotting to quantitate the transcription of mRNA [Thomas, Proc. Natl. Acad. Sci. USA, 77:5201-5205 (1980)], dot blotting (DNA analysis), or in situ hybridization, using an appropriately labeled probe, based on the sequences provided herein. Alternatively, antibodies may be employed that can recognize specific duplexes, including DNA duplexes, RNA duplexes, and DNA-RNA hybrid duplexes or DNA-protein duplexes. The antibodies in turn may be labeled and the assay may be carried out where the duplex is bound to a surface, so that upon the formation of duplex on the surface, the presence of antibody bound to the duplex can be detected.
Gene expression, alternatively, may be measured by immunological methods, such as immunohistochemical staining of cells or tissue sections and assay of cell culture or body fluids, to quantitate directly the expression of gene product. Antibodies useful for immunohistochemical staining and/or assay of sample fluids may be either monoclonal or polyclonal, and may be prepared in any mammal. Conveniently, the antibodies may be prepared against a native sequence TAHO polypeptide or against a synthetic peptide based on the DNA sequences provided herein or against exogenous sequence fused to TAHO DNA and encoding a specific antibody epitope.
6. Purification of Anti-TAHO Antibody and TAHO Polypeptide
Forms of anti-TAHO antibody and TAHO polypeptide may be recovered from culture medium or from host cell lysates. If membrane-bound, it can be released from the membrane using a suitable detergent solution (e.g. Triton-X 100) or by enzymatic cleavage. Cells employed in expression of anti-TAHO antibody and TAHO polypeptide can be disrupted by various physical or chemical means, such as freeze-thaw cycling, sonication, mechanical disruption, or cell lysing agents.
It may be desired to purify anti-TAHO antibody and TAHO polypeptide from recombinant cell proteins or polypeptides. The following procedures are exemplary of suitable purification procedures: by fractionation on an ion-exchange column; ethanol precipitation; reverse phase HPLC; chromatography on silica or on a cation-exchange resin such as DEAE; chromatofocusing; SDS-PAGE; ammonium sulfate precipitation; gel filtration using, for example, Sephadex G-75; protein A Sepharose columns to remove contaminants such as IgG; and metal chelating columns to bind epitope-tagged forms of the anti-TAHO antibody and TAHO polypeptide. Various methods of protein purification may be employed and such methods are known in the art and described for example in Deutscher, Methods in Enzymology, 182 (1990); Scopes, Protein Purification: Principles and Practice, Springer-Verlag, New York (1982). The purification step(s) selected will depend, for example, on the nature of the production process used and the particular anti-TAHO antibody or TAHO polypeptide produced.
When using recombinant techniques, the antibody can be produced intracellularly, in the periplasmic space, or directly secreted into the medium. If the antibody is produced intracellularly, as a first step, the particulate debris, either host cells or lysed fragments, are removed, for example, by centrifugation or ultrafiltration. Carter et al., Bio/Technology 10:163-167 (1992) describe a procedure for isolating antibodies which are secreted to the periplasmic space of E. coli. Briefly, cell paste is thawed in the presence of sodium acetate (pH 3.5), EDTA, and phenylmethylsulfonylfluoride (PMSF) over about 30 min. Cell debris can be removed by centrifugation. Where the antibody is secreted into the medium, supernatants from such expression systems are generally first concentrated using a commercially available protein concentration filter, for example, an Amicon or Millipore Pellicon ultrafiltration unit. A protease inhibitor such as PMSF may be included in any of the foregoing steps to inhibit proteolysis and antibiotics may be included to prevent the growth of adventitious contaminants.
The antibody composition prepared from the cells can be purified using, for example, hydroxylapatite chromatography, gel electrophoresis, dialysis, and affinity chromatography, with affinity chromatography being the preferred purification technique. The suitability of protein A as an affinity ligand depends on the species and isotype of any immunoglobulin Fc domain that is present in the antibody. Protein A can be used to purify antibodies that are based on human γ1, γ2 or γ4 heavy chains (Lindmark et al., J. Immunol. Meth. 62:1-13 (1983)). Protein G is recommended for all mouse isotypes and for human γ3 (Guss et al., EMBO J. 5:15671575 (1986)). The matrix to which the affinity ligand is attached is most often agarose, but other matrices are available. Mechanically stable matrices such as controlled pore glass or poly(styrenedivinyl)benzene allow for faster flow rates and shorter processing times than can be achieved with agarose. Where the antibody comprises a CH3 domain, the Bakerbond ABX™ resin (J. T. Baker, Phillipsburg, N.J.) is useful for purification. Other techniques for protein purification such as fractionation on an ion-exchange column, ethanol precipitation, Reverse Phase HPLC, chromatography on silica, chromatography on heparin SEPHAROSE™ chromatography on an anion or cation exchange resin (such as a polyaspartic acid column), chromatofocusing, SDS-PAGE, and ammonium sulfate precipitation are also available depending on the antibody to be recovered.
Following any preliminary purification step(s), the mixture comprising the antibody of interest and contaminants may be subjected to low pH hydrophobic interaction chromatography using an elution buffer at a pH between about 2.5-4.5, preferably performed at low salt concentrations (e.g., from about 0-0.25M salt).
J. Pharmaceutical Formulations
The antibody-drug conjugates (ADC) of the invention may be administered by any route appropriate to the condition to be treated. The ADC will typically be administered parenterally, i.e. infusion, subcutaneous, intramuscular, intravenous, intradermal, intrathecal and epidural.
For treating these cancers, in one embodiment, the antibody-drug conjugate is administered via intravenous infusion. The dosage administered via infusion is in the range of about 1 μg/m2 to about 10,000 μg/m2 per dose, generally one dose per week for a total of one, two, three or four doses. Alternatively, the dosage range is of about 1 μm2 to about 1000 μg/m2, about 1 μg/m2 to about 800 μg/m2, about 1 μg/m2 to about 600 μg/m2, about 1 μg/m2 to about 400 μg/m2, about 10 μg/m2 to about 500 μg/m2, about 10 μg/m2 to about 300 μg/m2, about 10 μg/m2 to about 200 μg/m2, and about 1 μg/m2 to about 200 μg/m2. The dose may be administered once per day, once per week, multiple times per week, but less than once per day, multiple times per month but less than once per day, multiple times per month but less than once per week, once per month or intermittently to relieve or alleviate symptoms of the disease. Administration may continue at any of the disclosed intervals until remission of the tumor or symptoms of the lymphoma, leukemia being treated. Administration may continue after remission or relief of symptoms is achieved where such remission or relief is prolonged by such continued administration.
The invention also provides a method of alleviating an autoimmune disease, comprising administering to a patient suffering from the autoimmune disease, a therapeutically effective amount of a anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40)-drug conjugate of any one of the preceding embodiments. In preferred embodiments the antibody is administered intravenously or subcutaneously. The antibody-drug conjugate is administered intravenously at a dosage in the range of about 1 μg/m2 to about 100 mg/m2 per dose and in a specific embodiment, the dosage is 1 μg/m2 to about 500 μg/m2. The dose may be administered once per day, once per week, multiple times per week, but less than once per day, multiple times per month but less than once per day, multiple times per month but less than once per week, once per month or intermittently to relieve or alleviate symptoms of the disease. Administration may continue at any of the disclosed intervals until relief from or alleviation of symptoms of the autoimmune disease being treated. Administration may continue after relief from or alleviation of symptoms is achieved where such alleviation or relief is prolong by such continued administration.
The invention also provides a method of treating a B cell disorder comprising administering to a patient suffering from a B cell disorder, such as a B cell proliferative disorder (including without limitation lymphoma and leukemia) or an autoimmune disease, a therapeutically effective amount of a SN8 antibody of any one of the preceding embodiments, which antibody is not conjugated to a cytotoxic molecule or a detectable molecule. The antibody will typically be administered in a dosage range of about 1 μg/m2 to about 1000 mg/m2.
In one aspect, the invention further provides pharmaeutical formulations comprising at least one anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), of the invention and/or at least one immunoconjugate thereof and/or at least one anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody-drug ocnjugate of the invention. In some embodiments, a pharmaceutical formulation comprises (1) an antibody of the invention and/or an immunoconjugate thereof, and (2) a pharmaceutically acceptable carrier. In some embodiments, a pharmaceutical formulation comprises (1) an antibody of the invention and/or an immunoconjugate thereof, and optionally, (2) at least one additional therapeutic agent. Additional therapeutic agents include, but are not limited to, those described below. The ADC will typically be administered parenterally, i.e. infusion, subcutaneous, intramuscular, intravenous, intradermal, intrathecal and epidural.
Therapeutic formulations of the anti-TAHO antibodies, TAHO binding oligopeptides, TAHO binding organic molecules and/or TAHO polypeptides used in accordance with the present invention are prepared for storage by mixing the antibody, polypeptide, oligopeptide or organic molecule having the desired degree of purity with optional pharmaceutically acceptable carriers, excipients or stabilizers (Remington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980)), in the form of lyophilized formulations or aqueous solutions. Acceptable carriers, excipients, or stabilizers are nontoxic to recipients at the dosages and concentrations employed, and include buffers such as acetate, Tris, phosphate, citrate, and other organic acids; antioxidants including ascorbic acid and methionine; preservatives (such as octadecyldimethylbenzyl ammonium chloride; hexamethonium chloride; benzalkonium chloride, benzethonium chloride; phenol, butyl or benzyl alcohol; alkyl parabens such as methyl or propyl paraben; catechol; resorcinol; cyclohexanol; 3-pentanol; and m-cresol); low molecular weight (less than about 10 residues) polypeptides; proteins, such as serum albumin, gelatin, or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; amino acids such as glycine, glutamine, asparagine, histidine, arginine, or lysine; monosaccharides, disaccharides, and other carbohydrates including glucose, mannose, or dextrins; chelating agents such as EDTA; tonicifiers such as trehalose and sodium chloride; sugars such as sucrose, mannitol, trehalose or sorbitol; surfactant such as polysorbate; salt-forming counter-ions such as sodium; metal complexes (e.g., Zn-protein complexes); and/or non-ionic surfactants such as TWEEN®, PLURONICS® or polyethylene glycol (PEG). The antibody preferably comprises the antibody at a concentration of between 5-200 mg/ml, preferably between 10-100 mg/ml.
The formulations herein may also contain more than one active compound as necessary for the particular indication being treated, preferably those with complementary activities that do not adversely affect each other. For example, in addition to an anti-TAHO antibody, TAHO binding oligopeptide, or TAHO binding organic molecule, it may be desirable to include in the one formulation, an additional antibody, e.g., a second anti-TAHO antibody which binds a different epitope on the TAHO polypeptide, or an antibody to some other target such as a growth factor that affects the growth of the particular cancer. Alternatively, or additionally, the composition may further comprise a chemotherapeutic agent, cytotoxic agent, cytokine, growth inhibitory agent, anti-hormonal agent, and/or cardioprotectant. Such molecules are suitably present in combination in amounts that are effective for the purpose intended.
The active ingredients may also be entrapped in microcapsules prepared, for example, by coacervation techniques or by interfacial polymerization, for example, hydroxymethylcellulose or gelatin-microcapsules and poly-(methylmethacylate) microcapsules, respectively, in colloidal drug delivery systems (for example, liposomes, albumin microspheres, microemulsions, nano-particles and nanocapsules) or in macroemulsions. Such techniques are disclosed in Remington's Pharmaceutical Sciences, 16th edition, Osol, A. Ed. (1980).
Sustained-release preparations may be prepared. Suitable examples of sustained-release preparations include semi-permeable matrices of solid hydrophobic polymers containing the antibody, which matrices are in the form of shaped articles, e.g., films, or microcapsules. Examples of sustained-release matrices include polyesters, hydrogels (for example, poly(2-hydroxyethyl-methacrylate), or poly(vinylalcohol)), polylactides (U.S. Pat. No. 3,773,919), copolymers of L-glutamic acid and γ ethyl-L-glutamate, non-degradable ethylene-vinyl acetate, degradable lactic acid-glycolic acid copolymers such as the LUPRON DEPOT® (injectable microspheres composed of lactic acid-glycolic acid copolymer and leuprolide acetate), and poly-D-(−)-3-hydroxybutyric acid.
The formulations to be used for in vivo administration must be sterile. This is readily accomplished by filtration through sterile filtration membranes.
K. Treatment with Anti-TAHO Antibodies, TAHO Binding Oligopeptides and TAHO Binding Organic Molecules
To determine TAHO expression in the cancer, various detection assays are available. In one embodiment, TAHO polypeptide overexpression may be analyzed by immunohistochemistry (IHC). Parrafin embedded tissue sections from a tumor biopsy may be subjected to the IHC assay and accorded a TAHO protein staining intensity criteria as follows:
Score 0— no staining is observed or membrane staining is observed in less than 10% of tumor cells.
Score 1+—a faint/barely perceptible membrane staining is detected in more than 10% of the tumor cells. The cells are only stained in part of their membrane.
Score 2+—a weak to moderate complete membrane staining is observed in more than 10% of the tumor cells.
Score 3+—a moderate to strong complete membrane staining is observed in more than 10% of the tumor cells.
Those tumors with 0 or 1+ scores for TAHO polypeptide expression may be characterized as not overexpressing TAHO, whereas those tumors with 2+ or 3+ scores may be characterized as overexpressing TAHO.
Alternatively, or additionally, FISH assays such as the INFORM® (sold by Ventana, Ariz.) or PATHVISION® (Vysis, Ill.) may be carried out on formalin-fixed, paraffin-embedded tumor tissue to determine the extent (if any) of TAHO overexpression in the tumor.
TAHO overexpression or amplification may be evaluated using an in vivo detection assay, e.g., by administering a molecule (such as an antibody, oligopeptide or organic molecule) which binds the molecule to be detected and is tagged with a detectable label (e.g., a radioactive isotope or a fluorescent label) and externally scanning the patient for localization of the label.
As described above, the anti-TAHO antibodies, oligopeptides and organic molecules of the invention have various non-therapeutic applications. The anti-TAHO antibodies, oligopeptides and organic molecules of the present invention can be useful for staging of TAHO polypeptide-expressing cancers (e.g., in radioimaging). The antibodies, oligopeptides and organic molecules are also useful for purification or immunoprecipitation of TAHO polypeptide from cells, for detection and quantitation of TAHO polypeptide in vitro, e.g., in an ELISA or a Western blot, to kill and eliminate TAHO-expressing cells from a population of mixed cells as a step in the purification of other cells.
Currently, depending on the stage of the cancer, cancer treatment involves one or a combination of the following therapies: surgery to remove the cancerous tissue, radiation therapy, and chemotherapy. Anti-TAHO antibody, oligopeptide or organic molecule therapy may be especially desirable in elderly patients who do not tolerate the toxicity and side effects of chemotherapy well and in metastatic disease where radiation therapy has limited usefulness. The tumor targeting anti-TAHO antibodies, oligopeptides and organic molecules of the invention are useful to alleviate TAHO-expressing cancers upon initial diagnosis of the disease or during relapse. For therapeutic applications, the anti-TAHO antibody, oligopeptide or organic molecule can be used alone, or in combination therapy with, e.g., hormones, antiangiogens, or radiolabelled compounds, or with surgery, cryotherapy, and/or radiotherapy. Anti-TAHO antibody, oligopeptide or organic molecule treatment can be administered in conjunction with other forms of conventional therapy, either consecutively with, pre- or post-conventional therapy. Chemotherapeutic drugs such as TAXOTERE® (docetaxel), TAXOL® (palictaxel), estramustine and mitoxantrone are used in treating cancer, in particular, in good risk patients. In the present method of the invention for treating or alleviating cancer, the cancer patient can be administered anti-TAHO antibody, oligopeptide or organic molecule in conjunction with treatment with the one or more of the preceding chemotherapeutic agents. In particular, combination therapy with palictaxel and modified derivatives (see, e.g., EP0600517) is contemplated. The anti-TAHO antibody, oligopeptide or organic molecule will be administered with a therapeutically effective dose of the chemotherapeutic agent. In another embodiment, the anti-TAHO antibody, oligopeptide or organic molecule is administered in conjunction with chemotherapy to enhance the activity and efficacy of the chemotherapeutic agent, e.g., paclitaxel. The Physicians' Desk Reference (PDR) discloses dosages of these agents that have been used in treatment of various cancers. The dosing regimen and dosages of these aforementioned chemotherapeutic drugs that are therapeutically effective will depend on the particular cancer being treated, the extent of the disease and other factors familiar to the physician of skill in the art and can be determined by the physician.
In one particular embodiment, a conjugate comprising an anti-TAHO antibody, oligopeptide or organic molecule conjugated with a cytotoxic agent is administered to the patient. Preferably, the immunoconjugate bound to the TAHO protein is internalized by the cell, resulting in increased therapeutic efficacy of the immunoconjugate in killing the cancer cell to which it binds. In a preferred embodiment, the cytotoxic agent targets or interferes with the nucleic acid in the cancer cell. Examples of such cytotoxic agents are described above and include maytansinoids, calicheamicins, ribonucleases and DNA endonucleases.
The anti-TAHO antibodies, oligopeptides, organic molecules or toxin conjugates thereof are administered to a human patient, in accord with known methods, such as intravenous administration, e.g., as a bolus or by continuous infusion over a period of time, by intramuscular, intraperitoneal, intracerobrospinal, subcutaneous, intra-articular, intrasynovial, intrathecal, oral, topical, or inhalation routes. Intravenous or subcutaneous administration of the antibody, oligopeptide or organic molecule is preferred.
Other therapeutic regimens may be combined with the administration of the anti-TAHO antibody, oligopeptide or organic molecule. The combined administration includes co-administration, using separate formulations or a single pharmaceutical formulation, and consecutive administration in either order, wherein preferably there is a time period while both (or all) active agents simultaneously exert their biological activities. Preferably such combined therapy results in a synergistic therapeutic effect.
It may also be desirable to combine administration of the anti-TAHO antibody or antibodies, oligopeptides or organic molecules, with administration of an antibody directed against another tumor antigen associated with the particular cancer.
In another embodiment, the therapeutic treatment methods of the present invention involves the combined administration of an anti-TAHO antibody (or antibodies), oligopeptides or organic molecules and one or more chemotherapeutic agents or growth inhibitory agents, including co-administration of cocktails of different chemotherapeutic agents. Chemotherapeutic agents include estramustine phosphate, prednimustine, cisplatin, 5-fluorouracil, melphalan, cyclophosphamide, hydroxyurea and hydroxyureataxanes (such as paclitaxel and doxetaxel) and/or anthracycline antibiotics. Preparation and dosing schedules for such chemotherapeutic agents may be used according to manufacturers' instructions or as determined empirically by the skilled practitioner. Preparation and dosing schedules for such chemotherapy are also described in Chemotherapy Service Ed., M. C. Perry, Williams & Wilkins, Baltimore, Md. (1992).
The antibody, oligopeptide or organic molecule may be combined with an anti-hormonal compound; e.g., an anti-estrogen compound such as tamoxifen; an anti-progesterone such as onapristone (see, EP 616 812); or an anti-androgen such as flutamide, in dosages known for such molecules. Where the cancer to be treated is androgen independent cancer, the patient may previously have been subjected to anti-androgen therapy and, after the cancer becomes androgen independent, the anti-TAHO antibody, oligopeptide or organic molecule (and optionally other agents as described herein) may be administered to the patient.
Sometimes, it may be beneficial to also co-administer a cardioprotectant (to prevent or reduce myocardial dysfunction associated with the therapy) or one or more cytokines to the patient. In addition to the above therapeutic regimes, the patient may be subjected to surgical removal of cancer cells and/or radiation therapy, before, simultaneously with, or post antibody, oligopeptide or organic molecule therapy. Suitable dosages for any of the above co-administered agents are those presently used and may be lowered due to the combined action (synergy) of the agent and anti-TAHO antibody, oligopeptide or organic molecule.
For the prevention or treatment of disease, the dosage and mode of administration will be chosen by the physician according to known criteria. The appropriate dosage of antibody, oligopeptide or organic molecule will depend on the type of disease to be treated, as defined above, the severity and course of the disease, whether the antibody, oligopeptide or organic molecule is administered for preventive or therapeutic purposes, previous therapy, the patient's clinical history and response to the antibody, oligopeptide or organic molecule, and the discretion of the attending physician. The antibody, oligopeptide or organic molecule is suitably administered to the patient at one time or over a series of treatments. Preferably, the antibody, oligopeptide or organic molecule is administered by intravenous infusion or by subcutaneous injections. Depending on the type and severity of the disease, about 1 μg/kg to about 50 mg/kg body weight (e.g., about 0.1-15 mg/kg/dose) of antibody can be an initial candidate dosage for administration to the patient, whether, for example, by one or more separate administrations, or by continuous infusion. A dosing regimen can comprise administering an initial loading dose of about 4 mg/kg, followed by a weekly maintenance dose of about 2 mg/kg of the anti-TAHO antibody. However, other dosage regimens may be useful. A typical daily dosage might range from about 1 μg/kg to 100 mg/kg or more, depending on the factors mentioned above. For repeated administrations over several days or longer, depending on the condition, the treatment is sustained until a desired suppression of disease symptoms occurs. The progress of this therapy can be readily monitored by conventional methods and assays and based on criteria known to the physician or other persons of skill in the art.
Aside from administration of the antibody protein to the patient, the present application contemplates administration of the antibody by gene therapy. Such administration of nucleic acid encoding the antibody is encompassed by the expression “administering a therapeutically effective amount of an antibody”. See, for example, WO96/07321 published Mar. 14, 1996 concerning the use of gene therapy to generate intracellular antibodies.
There are two major approaches to getting the nucleic acid (optionally contained in a vector) into the patient's cells; in vivo and ex vivo. For in vivo delivery the nucleic acid is injected directly into the patient, usually at the site where the antibody is required. For ex vivo treatment, the patient's cells are removed, the nucleic acid is introduced into these isolated cells and the modified cells are administered to the patient either directly or, for example, encapsulated within porous membranes which are implanted into the patient (see, e.g., U.S. Pat. Nos. 4,892,538 and 5,283,187). There are a variety of techniques available for introducing nucleic acids into viable cells. The techniques vary depending upon whether the nucleic acid is transferred into cultured cells in vitro, or in vivo in the cells of the intended host. Techniques suitable for the transfer of nucleic acid into mammalian cells in vitro include the use of liposomes, electroporation, microinjection, cell fusion, DEAE-dextran, the calcium phosphate precipitation method, etc. A commonly used vector for ex vivo delivery of the gene is a retroviral vector.
The currently preferred in vivo nucleic acid transfer techniques include transfection with viral vectors (such as adenovirus, Herpes simplex I virus, or adeno-associated virus) and lipid-based systems (useful lipids for lipid-mediated transfer of the gene are DOTMA, DOPE and DC-Chol, for example). For review of the currently known gene marking and gene therapy protocols see Anderson et al., Science 256:808-813 (1992). See also WO 93/25673 and the references cited therein.
The anti-TAHO antibodies of the invention can be in the different forms encompassed by the definition of “antibody” herein. Thus, the antibodies include full length or intact antibody, antibody fragments, native sequence antibody or amino acid variants, humanized, chimeric or fusion antibodies, immunoconjugates, and functional fragments thereof. In fusion antibodies an antibody sequence is fused to a heterologous polypeptide sequence. The antibodies can be modified in the Fc region to provide desired effector functions. As discussed in more detail in the sections herein, with the appropriate Fc regions, the naked antibody bound on the cell surface can induce cytotoxicity, e.g., via antibody-dependent cellular cytotoxicity (ADCC) or by recruiting complement in complement dependent cytotoxicity, or some other mechanism. Alternatively, where it is desirable to eliminate or reduce effector function, so as to minimize side effects or therapeutic complications, certain other Fc regions may be used.
In one embodiment, the antibody competes for binding or bind substantially to, the same epitope as the antibodies of the invention. Antibodies having the biological characteristics of the present anti-TAHO antibodies of the invention are also contemplated, specifically including the in vivo tumor targeting and any cell proliferation inhibition or cytotoxic characteristics.
Methods of producing the above antibodies are described in detail herein.
The present anti-TAHO antibodies, oligopeptides and organic molecules are useful for treating a TAHO-expressing cancer or alleviating one or more symptoms of the cancer in a mammal. Such a cancer includes, but is not limited to, hematopoietic cancers or blood-related cancers, such as lymphoma, leukemia, myeloma or lymphoid malignancies, but also cancers of the spleen and cancers of the lymph nodes. More particular examples of such B-cell associated cancers, including for example, high, intermediate and low grade lymphomas (including B cell lymphomas such as, for example, mucosa-associated-lymphoid tissue B cell lymphoma and non-Hodgkin's lymphoma, mantle cell lymphoma, Burkitt's lymphoma, small lymphocytic lymphoma, marginal zone lymphoma, diffuse large cell lymphoma, follicular lymphoma, and Hodgkin's lymphoma and T cell lymphomas) and leukemias (including secondary leukemia, chronic lymphocytic leukemia, such as B cell leukemia (CD5+ B lymphocytes), myeloid leukemia, such as acute myeloid leukemia, chronic myeloid leukemia, lymphoid leukemia, such as acute lymphoblastic leukemia and myelodysplasia), multiple myeloma, such as plasma cell malignancy, and other hematological and/or B cell- or T-cell-associated cancers. The cancers encompass metastatic cancers of any of the preceding. The antibody, oligopeptide or organic molecule is able to bind to at least a portion of the cancer cells that express TAHO polypeptide in the mammal. In a preferred embodiment, the antibody, oligopeptide or organic molecule is effective to destroy or kill TAHO-expressing tumor cells or inhibit the growth of such tumor cells, in vitro or in vivo, upon binding to TAHO polypeptide on the cell. Such an antibody includes a naked anti-TAHO antibody (not conjugated to any agent). Naked antibodies that have cytotoxic or cell growth inhibition properties can be further harnessed with a cytotoxic agent to render them even more potent in tumor cell destruction. Cytotoxic properties can be conferred to an anti-TAHO antibody by, e.g., conjugating the antibody with a cytotoxic agent, to form an immunoconjugate as described herein. The cytotoxic agent or a growth inhibitory agent is preferably a small molecule. Toxins such as calicheamicin or a maytansinoid and analogs or derivatives thereof, are preferable.
The invention provides a composition comprising an anti-TAHO antibody, oligopeptide or organic molecule of the invention, and a carrier. For the purposes of treating cancer, compositions can be administered to the patient in need of such treatment, wherein the composition can comprise one or more anti-TAHO antibodies present as an immunoconjugate or as the naked antibody. In a further embodiment, the compositions can comprise these antibodies, oligopeptides or organic molecules in combination with other therapeutic agents such as cytotoxic or growth inhibitory agents, including chemotherapeutic agents. The invention also provides formulations comprising an anti-TAHO antibody, oligopeptide or organic molecule of the invention, and a carrier. In one embodiment, the formulation is a therapeutic formulation comprising a pharmaceutically acceptable carrier.
Another aspect of the invention is isolated nucleic acids encoding the anti-TAHO antibodies. Nucleic acids encoding both the H and L chains and especially the hypervariable region residues, chains which encode the native sequence antibody as well as variants, modifications and humanized versions of the antibody, are encompassed.
The invention also provides methods useful for treating a TAHO polypeptide-expressing cancer or alleviating one or more symptoms of the cancer in a mammal, comprising administering a therapeutically effective amount of an anti-TAHO antibody, oligopeptide or organic molecule to the mammal. The antibody, oligopeptide or organic molecule therapeutic compositions can be administered short term (acute) or chronic, or intermittent as directed by physician. Also provided are methods of inhibiting the growth of, and killing a TAHO polypeptide-expressing cell.
The invention also provides kits and articles of manufacture comprising at least one anti-TAHO antibody, oligopeptide or organic molecule. Kits containing anti-TAHO antibodies, oligopeptides or organic molecules find use, e.g., for TAHO cell killing assays, for purification or immunoprecipitation of TAHO polypeptide from cells. For example, for isolation and purification of TAHO, the kit can contain an anti-TAHO antibody, oligopeptide or organic molecule coupled to beads (e.g., sepharose beads). Kits can be provided which contain the antibodies, oligopeptides or organic molecules for detection and quantitation of TAHO in vitro, e.g., in an ELISA or a Western blot. Such antibody, oligopeptide or organic molecule useful for detection may be provided with a label such as a fluorescent or radiolabel.
L. Antibody-Drug Conjugate Treatments
It is contemplated that the antibody-drug conjugates (ADC) of the present invention may be used to treat various diseases or disorders, e.g. characterized by the overexpression of a tumor antigen. Exemplary conditions or hyperproliferative disorders include benign or malignant tumors; leukemia and lymphoid malignancies. Others include neuronal, glial, astrocytal, hypothalamic, glandular, macrophagal, epithelial, stromal, blastocoelic, inflammatory, angiogenic and immunologic, including autoimmune, disorders.
The ADC compounds which are identified in the animal models and cell-based assays can be further tested in tumor-bearing higher primates and human clinical trials. Human clinical trials can be designed to test the efficacy of the anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), monoclonal antibody or immunoconjugate of the invention in patients experiencing a B cell proliferative disorder including without limitation lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma. The clinical trial may be designed to evaluate the efficacy of an ADC in combinations with known therapeutic regimens, such as radiation and/or chemotherapy involving known chemotherapeutic and/or cytotoxic agents.
Generally, the disease or disorder to be treated is a hyperproliferative disease such as a B cell proliferative disorder and/or a B cell cancer. Examples of cancer to be treated herein include, but are not limited to, B cell proliferative disorder is selected from lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
The cancer may comprise TAHO-expressing cells, such as human CD79b (TAHO5) or cyno CD79b (TAHO40)-expressing cells, such that the ADC of the present invention are able to bind to the cancer cells. To determine TAHO polypeptide, such as human CD79b (TAHOS) or cyno CD79b (TAHO40), expression in the cancer, various diagnostic/prognostic assays are available. In one embodiment, TAHO polypeptide, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), overexpression may be analyzed by IHC. Parrafin-embedded tissue sections from a tumor biopsy may be subjected to the IHC assay and accorded a TAHO protein, such as human CD79b (TAHO5) or cyno CD79b (TAHO40), staining intensity criteria with respect to the degree of staining and in what proportion of tumor cells examined.
For the prevention or treatment of disease, the appropriate dosage of an ADC will depend on the type of disease to be treated, as defined above, the severity and course of the disease, whether the molecule is administered for preventive or therapeutic purposes, previous therapy, the patient's clinical history and response to the antibody, and the discretion of the attending physician. The molecule is suitably administered to the patient at one time or over a series of treatments. Depending on the type and severity of the disease, about 1 μg/kg to 15 mg/kg (e.g. 0.1-20 mg/kg) of molecule is an initial candidate dosage for administration to the patient, whether, for example, by one or more separate administrations, or by continuous infusion. A typical daily dosage might range from about 1 μg/kg to 100 mg/kg or more, depending on the factors mentioned above. An exemplary dosage of ADC to be administered to a patient is in the range of about 0.1 to about 10 mg/kg of patient weight.
For repeated administrations over several days or longer, depending on the condition, the treatment is sustained until a desired suppression of disease symptoms occurs. An exemplary dosing regimen comprises administering an initial loading dose of about 4 mg/kg, followed by a weekly maintenance dose of about 2 mg/kg of an anti-ErbB2 antibody. Other dosage regimens may be useful. The progress of this therapy is easily monitored by conventional techniques and assays.
M. Combination Therapy
An antibody-drug conjugate (ADC) of the invention may be combined in a pharmaceutical combination formulation, or dosing regimen as combination therapy, with a second compound having anti-cancer properties. The second compound of the pharmaceutical combination formulation or dosing regimen preferably has complementary activities to the ADC of the combination such that they do not adversely affect each other.
The second compound may be a chemotherapeutic agent, cytotoxic agent, cytokine, growth inhibitory agent, anti-hormonal agent, and/or cardioprotectant. Such molecules are suitably present in combination in amounts that are effective for the purpose intended. A pharmaceutical composition containing an ADC of the invention may also have a therapeutically effective amount of a chemotherapeutic agent such as a tubulin-forming inhibitor, a topoisomerase inhibitor, or a DNA binder.
In one aspect, the first compound is an anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), ADC of the invention and the second compound is an anti-CD20 antibody (either a naked antibody or an ADC). In one embodiment the second compound is an anti-CD20 antibody rituximab (Rituxan®) or 2H7 (Genentech, Inc., South San Francisco, Calif.). Another antibodies useful for combined immunotherapy with anti-CD79b ADCs of the invention includes without limitation, anti-VEGF (e.g., Avastin®).
Other therapeutic regimens may be combined with the administration of an anticancer agent identified in accordance with this invention, including without limitation radiation therapy and/or bone marrow and peripheral blood transplants, and/or a cytotoxic agent, a chemotherapeutic agent, or a growth inhibitory agent. In one of such embodiments, a chemotherapeutic agent is an agent or a combination of agents such as, for example, cyclophosphamide, hydroxydaunorubicin, adriamycin, doxorubincin, vincristine (Oncovin™), prednisolone, CHOP, CVP, or COP, or immunotherapeutics such as anti-CD20 (e.g., Rituxan®) or anti-VEGF (e.g., Avastin®).
The combination therapy may be administered as a simultaneous or sequential regimen. When administered sequentially, the combination may be administered in two or more administrations. The combined administration includes coadministration, using separate formulations or a single pharmaceutical formulation, and consecutive administration in either order, wherein preferably there is a time period while both (or all) active agents simultaneously exert their biological activities.
In one embodiment, treatment with an ADC involves the combined administration of an anticancer agent identified herein, and one or more chemotherapeutic agents or growth inhibitory agents, including coadministration of cocktails of different chemotherapeutic agents. Chemotherapeutic agents include taxanes (such as paclitaxel and docetaxel) and/or anthracycline antibiotics. Preparation and dosing schedules for such chemotherapeutic agents may be used according to manufacturer's instructions or as determined empirically by the skilled practitioner. Preparation and dosing schedules for such chemotherapy are also described in “Chemotherapy Service”, (1992) Ed., M. C. Perry, Williams & Wilkins, Baltimore, Md.
Suitable dosages for any of the above coadministered agents are those presently used and may be lowered due to the combined action (synergy) of the newly identified agent and other chemotherapeutic agents or treatments.
The combination therapy may provide “synergy” and prove “synergistic”, i.e. the effect achieved when the active ingredients used together is greater than the sum of the effects that results from using the compounds separately. A synergistic effect may be attained when the active ingredients are: (1) co-formulated and administered or delivered simultaneously in a combined, unit-dosage formulation; (2) delivered by alternation or in parallel as separate formulations; or (3) by some other regimen. When delivered in alternation therapy, a synergistic effect may be attained when the compounds are administered or delivered sequentially, e.g. by different injections in separate syringes. In general, during alternation therapy, an effective dosage of each active ingredient is administered sequentially, i.e. serially, whereas in combination therapy, effective dosages of two or more active ingredients are administered together.
N. Articles of Manufacture and Kits
Another embodiment of the invention is an article of manufacture containing materials useful for the treatment of anti-TAHO expressing cancer. The article of manufacture comprises a container and a label or package insert on or associated with the container. Suitable containers include, for example, bottles, vials, syringes, etc. The containers may be formed from a variety of materials such as glass or plastic. The container holds a composition which is effective for treating the cancer condition and may have a sterile access port (for example the container may be an intravenous solution bag or a vial having a stopper pierceable by a hypodermic injection needle). At least one active agent in the composition is an anti-TAHO antibody, oligopeptide or organic molecule of the invention. The label or package insert indicates that the composition is used for treating cancer. The label or package insert will further comprise instructions for administering the antibody, oligopeptide or organic molecule composition to the cancer patient. Additionally, the article of manufacture may further comprise a second container comprising a pharmaceutically-acceptable buffer, such as bacteriostatic water for injection (BWFI), phosphate-buffered saline, Ringer's solution and dextrose solution. It may further include other materials desirable from a commercial and user standpoint, including other buffers, diluents, filters, needles, and syringes.
Kits are also provided that are useful for various purposes, e.g., for TAHO-expressing cell killing assays, for purification or immunoprecipitation of TAHO polypeptide from cells. For isolation and purification of TAHO polypeptide, the kit can contain an anti-TAHO antibody, oligopeptide or organic molecule coupled to beads (e.g., sepharose beads). Kits can be provided which contain the antibodies, oligopeptides or organic molecules for detection and quantitation of TAHO polypeptide in vitro, e.g., in an ELISA or a Western blot. As with the article of manufacture, the kit comprises a container and a label or package insert on or associated with the container. The container holds a composition comprising at least one anti-TAHO antibody, oligopeptide or organic molecule of the invention. Additional containers may be included that contain, e.g., diluents and buffers, control antibodies. The label or package insert may provide a description of the composition as well as instructions for the intended in vitro or detection use.
O. Uses for TAHO Polypeptides and TAHO-Polypeptide Encoding Nucleic Acids
Nucleotide sequences (or their complement) encoding TAHO polypeptides have various applications in the art of molecular biology, including uses as hybridization probes, in chromosome and gene mapping and in the generation of anti-sense RNA and DNA probes. TAHO-encoding nucleic acid will also be useful for the preparation of TAHO polypeptides by the recombinant techniques described herein, wherein those TAHO polypeptides may find use, for example, in the preparation of anti-TAHO antibodies as described herein.
The full-length native sequence TAHO gene, or portions thereof, may be used as hybridization probes for a cDNA library to isolate the full-length TAHO cDNA or to isolate still other cDNAs (for instance, those encoding naturally-occurring variants of TAHO or TAHO from other species) which have a desired sequence identity to the native TAHO sequence disclosed herein. Optionally, the length of the probes will be about 20 to about 50 bases. The hybridization probes may be derived from at least partially novel regions of the full length native nucleotide sequence wherein those regions may be determined without undue experimentation or from genomic sequences including promoters, enhancer elements and introns of native sequence TAHO. By way of example, a screening method will comprise isolating the coding region of the TAHO gene using the known DNA sequence to synthesize a selected probe of about 40 bases. Hybridization probes may be labeled by a variety of labels, including radionucleotides such as 32P or 35S, or enzymatic labels such as alkaline phosphatase coupled to the probe via avidin/biotin coupling systems. Labeled probes having a sequence complementary to that of the TAHO gene of the present invention can be used to screen libraries of human cDNA, genomic DNA or mRNA to determine which members of such libraries the probe hybridizes to. Hybridization techniques are described in further detail in the Examples below. Any EST sequences disclosed in the present application may similarly be employed as probes, using the methods disclosed herein.
Other useful fragments of the TAHO-encoding nucleic acids include antisense or sense oligonucleotides comprising a singe-stranded nucleic acid sequence (either RNA or DNA) capable of binding to target TAHO mRNA (sense) or TAHO DNA (antisense) sequences. Antisense or sense oligonucleotides, according to the present invention, comprise a fragment of the coding region of TAHO DNA. Such a fragment generally comprises at least about 14 nucleotides, preferably from about 14 to 30 nucleotides. The ability to derive an antisense or a sense oligonucleotide, based upon a cDNA sequence encoding a given protein is described in, for example, Stein and Cohen (Cancer Res. 48:2659, 1988) and van der Krol et al. (BioTechniques 6:958, 1988).
Binding of antisense or sense oligonucleotides to target nucleic acid sequences results in the formation of duplexes that block transcription or translation of the target sequence by one of several means, including enhanced degradation of the duplexes, premature termination of transcription or translation, or by other means. Such methods are encompassed by the present invention. The antisense oligonucleotides thus may be used to block expression of TAHO proteins, wherein those TAHO proteins may play a role in the induction of cancer in mammals. Antisense or sense oligonucleotides further comprise oligonucleotides having modified sugat-phosphodiester backbones (or other sugar linkages, such as those described in WO 91/06629) and wherein such sugar linkages are resistant to endogenous nucleases. Such oligonucleotides with resistant sugar linkages are stable in vivo (i.e., capable of resisting enzymatic degradation) but retain sequence specificity to be able to bind to target nucleotide sequences.
Preferred intragenic sites for antisense binding include the region incorporating the translation initiation/start codon (5′-AUG/5′-ATG) or termination/stop codon (5′-UAA, 5′-UAG and 5-UGA/5′-TAA, 5′-TAG and 5′-TGA) of the open reading frame (ORF) of the gene. These regions refer to a portion of the mRNA or gene that encompasses from about 25 to about 50 contiguous nucleotides in either direction (i.e., 5′ or 3′) from a translation initiation or termination codon. Other preferred regions for antisense binding include: introns; exons; intron-exon junctions; the open reading frame (ORF) or “coding region,” which is the region between the translation initiation codon and the translation termination codon; the 5′ cap of an mRNA which comprises an N7-methylated guanosine residue joined to the 5′-most residue of the mRNA via a 5′-5′ triphosphate linkage and includes 5′ cap structure itself as well as the first 50 nucleotides adjacent to the cap; the 5′ untranslated region (5′UTR), the portion of an mRNA in the 5′ direction from the translation initiation codon, and thus including nucleotides between the 5′ cap site and the translation initiation codon of an mRNA or corresponding nucleotides on the gene; and the 3′ untranslated region (3′UTR), the portion of an mRNA in the 3′ direction from the translation termination codon, and thus including nucleotides between the translation termination codon and 3′ end of an mRNA or corresponding nucleotides on the gene.
Specific examples of preferred antisense compounds useful for inhibiting expression of TAHO proteins include oligonucleotides containing modified backbones or non-natural internucleoside linkages. Oligonucleotides having modified backbones include those that retain a phosphorus atom in the backbone and those that do not have a phosphorus atom in the backbone. For the purposes of this specification, and as sometimes referenced in the art, modified oligonucleotides that do not have a phosphorus atom in their internucleoside backbone can also be considered to be oligonucleosides. Preferred modified oligonucleotide backbones include, for example, phosphorothioates, chiral phosphorothioates, phosphorodithioates, phosphotriesters, aminoalkylphosphotri-esters, methyl and other alkyl phosphonates including 3′-alkylene phosphonates, 5′-alkylene phosphonates and chiral phosphonates, phosphinates, phosphoramidates including 3′-amino phosphoramidate and aminoalkylphosphoramidates, thionophosphoramidates, thionoalkylphosphonates, thionoalkylphosphotriesters, selenophosphates and borano-phosphates having normal 3′-5′ linkages, 2′-5′ linked analogs of these, and those having inverted polarity wherein one or more internucleotide linkages is a 3′ to 3′, 5′ to 5′ or 2′ to 2′ linkage. Preferred oligonucleotides having inverted polarity comprise a single 3′ to 3′ linkage at the 3′-most internucleotide linkage i.e. a single inverted nucleoside residue which may be abasic (the nucleobase is missing or has a hydroxyl group in place thereof). Various salts, mixed salts and free acid forms are also included. Representative United States patents that teach the preparation of phosphorus-containing linkages include, but are not limited to, U.S. Pat. Nos. 3,687,808; 4,469,863; 4,476,301; 5,023,243; 5,177,196; 5,188,897; 5,264,423; 5,276,019; 5,278,302; 5,286,717; 5,321,131; 5,399,676; 5,405,939; 5,453,496; 5,455,233; 5,466,677; 5,476,925; 5,519,126; 5,536,821; 5,541,306; 5,550,111; 5,563,253; 5,571,799; 5,587,361; 5,194,599; 5,565,555; 5,527,899; 5,721,218; 5,672,697 and 5,625,050, each of which is herein incorporated by reference.
Preferred modified oligonucleotide backbones that do not include a phosphorus atom therein have backbones that are formed by short chain alkyl or cycloalkyl internucleoside linkages, mixed heteroatom and alkyl or cycloalkyl internucleoside linkages, or one or more short chain heteroatomic or heterocyclic internucleoside linkages. These include those having morpholino linkages (formed in part from the sugar portion of a nucleoside); siloxane backbones; sulfide, sulfoxide and sulfone backbones; formacetyl and thioformacetyl backbones; methylene formacetyl and thioformacetyl backbones; riboacetyl backbones; alkene containing backbones; sulfamate backbones; methyleneimino and methylenehydrazino backbones; sulfonate and sulfonamide backbones; amide backbones; and others having mixed N, O, S and CH.sub.2 component parts. Representative United States patents that teach the preparation of such oligonucleosides include, but are not limited to, U.S. Pat. Nos. 5,034,506; 5,166,315; 5,185,444; 5,214,134; 5,216,141; 5,235,033; 5,264,562; 5,264,564; 5,405,938; 5,434,257; 5,466,677; 5,470,967; 5,489,677; 5,541,307; 5,561,225; 5,596,086; 5,602,240; 5,610,289; 5,602,240; 5,608,046; 5,610,289; 5,618,704; 5,623,070; 5,663,312; 5,633,360; 5,677,437; 5,792,608; 5,646,269 and 5,677,439, each of which is herein incorporated by reference.
In other preferred antisense oligonucleotides, both the sugar and the internucleoside linkage, i.e., the backbone, of the nucleotide units are replaced with novel groups. The base units are maintained for hybridization with an appropriate nucleic acid target compound. One such oligomeric compound, an oligonucleotide mimetic that has been shown to have excellent hybridization properties, is referred to as a peptide nucleic acid (PNA). In PNA compounds, the sugar-backbone of an oligonucleotide is replaced with an amide containing backbone, in particular an aminoethylglycine, backbone. The nucleobases are retained and are bound directly or indirectly to aza nitrogen atoms of the amide portion of the backbone. Representative United States patents that teach the preparation of PNA compounds include, but are not limited to, U.S. Pat. Nos. 5,539,082; 5,714,331; and 5,719,262, each of which is herein incorporated by reference. Further teaching of PNA compounds can be found in Nielsen et al., Science, 1991, 254, 1497-1500.
Preferred antisense oligonucleotides incorporate phosphorothioate backbones and/or heteroatom backbones, and in particular —CH2—NH—O—CH2—, —CH2—N(CH3)—O—CH2— [known as a methylene (methylimino) or MMI backbone], —CH2—O—N(CH3)—CH2—, —CH2—N(CH3)—N(CH3)—CH2— and —O—N(CH3)—CH2—CH2— [wherein the native phosphodiester backbone is represented as —O—P—O—CH2—] described in the above referenced U.S. Pat. No. 5,489,677, and the amide backbones of the above referenced U.S. Pat. No. 5,602,240. Also preferred are antisense oligonucleotides having morpholino backbone structures of the above-referenced U.S. Pat. No. 5,034,506.
Modified oligonucleotides may also contain one or more substituted sugar moieties. Preferred oligonucleotides comprise one of the following at the 2′ position: OH; F; O-alkyl, S-alkyl, or N-alkyl; O-alkenyl, S-alkeynyl, or N-alkenyl; O-alkynyl, S-alkynyl or N-alkynyl; or O-alkyl-O-alkyl, wherein the alkyl, alkenyl and alkynyl may be substituted or unsubstituted C1 to C10 alkyl or C2 to C10 alkenyl and alkynyl. Particularly preferred are O[(CH2)nO]mCH3, O(CH2)nOCH3, O(CH2)nNH2, O(CH2)nCH3, O(CH2)nONH2, and O(CH2)nON[(CH2)nCH3)]2, where n and m are from 1 to about 10. Other preferred antisense oligonucleotides comprise one of the following at the 2′ position: C1 to C10 lower alkyl, substituted lower alkyl, alkenyl, alkynyl, alkaryl, aralkyl, O-alkaryl or O-aralkyl, SH, SCH3, OCN, Cl, Br, CN, CF3, OCF3, SOCH3, SO2 CH3, ONO2, NO2, N3, NH2, heterocycloalkyl, heterocycloalkaryl, aminoalkylamino, polyalkylamino, substituted silyl, an RNA cleaving group, a reporter group, an intercalator, a group for improving the pharmacokinetic properties of an oligonucleotide, or a group for improving the pharmacodynamic properties of an oligonucleotide, and other substituents having similar properties. A preferred modification includes 2′-methoxyethoxy (2′-O—CH2CH2OCH3, also known as 2′-O-(2-methoxyethyl) or 2′-MOE) (Martin et al., Helv. Chim. Acta, 1995, 78, 486-504) i.e., an alkoxyalkoxy group. A further preferred modification includes 2′-dimethylaminooxyethoxy, i.e., a O(CH2)2ON(CH3)2 group, also known as 2′-DMAOE, as described in examples herein below, and 2′-dimethylaminoethoxyethoxy (also known in the art as 2′-O-dimethylaminoethoxyethyl or 2′-DMAEOE), i.e., 2′-O—CH2—O—CH2—N(CH2).
A further preferred modification includes Locked Nucleic Acids (LNAs) in which the 2′-hydroxyl group is linked to the 3′ or 4′ carbon atom of the sugar ring thereby forming a bicyclic sugar moiety. The linkage is preferably a methelyne (—CH2—)n group bridging the 2′ oxygen atom and the 4′ carbon atom wherein n is 1 or 2. LNAs and preparation thereof are described in WO 98/39352 and WO 99/14226.
Other preferred modifications include 2′-methoxy (2′-O—CH3), 2′-aminopropoxy (2′-OCH2CH2CH2NH2), 2′-allyl (2′-CH2—CH═CH2), 2′-O-allyl (2′-O—CH2—CH═CH2) and 2′-fluoro (2′-F). The 2′-modification may be in the arabino (up) position or ribo (down) position. A preferred 2′-arabino modification is 2′-F. Similar modifications may also be made at other positions on the oligonucleotide, particularly the 3′ position of the sugar on the 3′ terminal nucleotide or in 2′-5′ linked oligonucleotides and the 5′ position of 5′ terminal nucleotide. Oligonucleotides may also have sugar mimetics such as cyclobutyl moieties in place of the pentofuranosyl sugar. Representative United States patents that teach the preparation of such modified sugar structures include, but are not limited to, U.S. Pat. Nos. 4,981,957; 5,118,800; 5,319,080; 5,359,044; 5,393,878; 5,446,137; 5,466,786; 5,514,785; 5,519,134; 5,567,811; 5,576,427; 5,591,722; 5,597,909; 5,610,300; 5,627,053; 5,639,873; 5,646,265; 5,658,873; 5,670,633; 5,792,747; and 5,700,920, each of which is herein incorporated by reference in its entirety.
Oligonucleotides may also include nucleobase (often referred to in the art simply as “base”) modifications or substitutions. As used herein, “unmodified” or “natural” nucleobases include the purine bases adenine (A) and guanine (G), and the pyrimidine bases thymine (T), cytosine (C) and uracil (U). Modified nucleobases include other synthetic and natural nucleobases such as 5-methylcytosine (5-me-C), 5-hydroxymethyl cytosine, xanthine, hypoxanthine, 2-aminoadenine, 6-methyl and other alkyl derivatives of adenine and guanine, 2-propyl and other alkyl derivatives of adenine and guanine, 2-thiouracil, 2-thiothymine and 2-thiocytosine, 5-halouracil and cytosine, 5-propynyl (—C≡C—CH3 or —CH2—C≡CH) uracil and cytosine and other alkynyl derivatives of pyrimidine bases, 6-azo uracil, cytosine and thymine, 5-uracil (pseudouracil), 4-thiouracil, 8-halo, 8-amino, 8-thiol, 8-thioalkyl, 8-hydroxyl and other 8-substituted adenines and guanines, 5-halo particularly 5-bromo, 5-trifluoromethyl and other 5-substituted uracils and cytosines, 7-methylguanine and 7-methyladenine, 2-F-adenine, 2-amino-adenine, 8-azaguanine and 8-azaadenine, 7-deazaguanine and 7-deazaadenine and 3-deazaguanine and 3-deazaadenine. Further modified nucleobases include tricyclic pyrimidines such as phenoxazine cytidine(1H-pyrimido[5,4-b][1,4]benzoxazin-2(3H)-one), phenothiazine cytidine (1H-pyrimido[5,4-b][1,4]benzothiazin-2(3H)-one), G-clamps such as a substituted phenoxazine cytidine (e.g. 9-(2-aminoethoxy)-H-pyrimido[5,4-b][1,4]benzoxazin-2(3H)-one), carbazole cytidine (2H-pyrimido[4,5-b]indol-2-one), pyridoindole cytidine (H-pyrido[3′,2′:4,5]pyrrolo[2,3-d]pyrimidin-2-one). Modified nucleobases may also include those in which the purine or pyrimidine base is replaced with other heterocycles, for example 7-deaza-adenine, 7-deazaguanosine, 2-aminopyridine and 2-pyridone. Further nucleobases include those disclosed in U.S. Pat. No. 3,687,808, those disclosed in The Concise Encyclopedia Of Polymer Science And Engineering, pages 858-859, Kroschwitz, J. I., ed. John Wiley & Sons, 1990, and those disclosed by Englisch et al., Angewandte Chemie, International Edition, 1991, 30, 613. Certain of these nucleobases are particularly useful for increasing the binding affinity of the oligomeric compounds of the invention. These include 5-substituted pyrimidines, 6-azapyrimidines and N-2, N-6 and O-6 substituted purines, including 2-aminopropyladenine, 5-propynyluracil and 5-propynylcytosine. 5-methylcytosine substitutions have been shown to increase nucleic acid duplex stability by 0.6-1.2.degree. C. (Sanghvi et al, Antisense Research and Applications, CRC Press, Boca Raton, 1993, pp. 276-278) and are preferred base substitutions, even more particularly when combined with 2′-O-methoxyethyl, sugar modifications. Representative United States patents that teach the preparation of modified nucleobases include, but are not limited to: U.S. Pat. No. 3,687,808, as well as U.S. Pat. Nos. 4,845,205; 5,130,302; 5,134,066; 5,175,273; 5,367,066; 5,432,272; 5,457,187; 5,459,255; 5,484,908; 5,502,177; 5,525,711; 5,552,540; 5,587,469; 5,594,121, 5,596,091; 5,614,617; 5,645,985; 5,830,653; 5,763,588; 6,005,096; 5,681,941 and 5,750,692, each of which is herein incorporated by reference.
Another modification of antisense oligonucleotides chemically linking to the oligonucleotide one or more moieties or conjugates which enhance the activity, cellular distribution or cellular uptake of the oligonucleotide. The compounds of the invention can include conjugate groups covalently bound to functional groups such as primary or secondary hydroxyl groups. Conjugate groups of the invention include intercalators, reporter molecules, polyamines, polyamides, polyethylene glycols, polyethers, groups that enhance the pharmacodynamic properties of oligomers, and groups that enhance the pharmacokinetic properties of oligomers. Typical conjugates groups include cholesterols, lipids, cation lipids, phospholipids, cationic phospholipids, biotin, phenazine, folate, phenanthridine, anthraquinone, acridine, fluoresceins, rhodamines, coumarins, and dyes. Groups that enhance the pharmacodynamic properties, in the context of this invention, include groups that improve oligomer uptake, enhance oligomer resistance to degradation, and/or strengthen sequence-specific hybridization with RNA. Groups that enhance the pharmacokinetic properties, in the context of this invention, include groups that improve oligomer uptake, distribution, metabolism or excretion. Conjugate moieties include but are not limited to lipid moieties such as a cholesterol moiety (Letsinger et al., Proc. Natl. Acad. Sci. USA, 1989, 86, 6553-6556), cholic acid (Manoharan et al., Bioorg. Med. Chem. Let., 1994, 4, 1053-1060), a thioether, e.g., hexyl-S-tritylthiol (Manoharan et al., Ann. N.Y. Acad. Sci., 1992, 660, 306-309; Manoharan et al., Bioorg. Med. Chem. Let., 1993, 3, 2765-2770), a thiocholesterol (Oberhauser et al., Nucl. Acids Res., 1992, 20, 533-538), an aliphatic chain, e.g., dodecandiol or undecyl residues (Saison-Behmoaras et al., EMBO J., 1991, 10, 1111-1118; Kabanov et al., FEBS Lett., 1990, 259, 327-330; Svinarchuk et al., Biochimie, 1993, 75, 49-54), a phospholipid, e.g., di-hexadecyl-rac-glycerol or triethyl-ammonium 1,2-di-O-hexadecyl-rac-glycero-3-H-phosphonate (Manoharan et al., Tetrahedron Lett., 1995, 36, 3651-3654; Shea et al., Nucl. Acids Res., 1990, 18, 3777-3783), a polyamine or a polyethylene glycol chain (Manoharan et al., Nucleosides & Nucleotides, 1995, 14, 969-973), or adamantane acetic acid (Manoharan et al., Tetrahedron Lett., 1995, 36, 3651-3654), a palmityl moiety (Mishra et al., Biochim. Biophys. Acta, 1995, 1264, 229-237), or an octadecylamine or hexylamino-carbonyl-oxycholesterol moiety. Oligonucleotides of the invention may also be conjugated to active drug substances, for example, aspirin, warfarin, phenylbutazone, ibuprofen, suprofen, fenbufen, ketoprofen, (S)-(+)-pranoprofen, carprofen, dansylsarcosine, 2,3,5-triiodobenzoic acid, flufenamic acid, folinic acid, a benzothiadiazide, chlorothiazide, a diazepine, indomethicin, a barbiturate, a cephalosporin, a sulfa drug, an antidiabetic, an antibacterial or an antibiotic. Oligonucleotide-drug conjugates and their preparation are described in U.S. patent application Ser. No. 09/334,130 (filed Jun. 15, 1999) and U.S. Pat. Nos. 4,828,979; 4,948,882; 5,218,105; 5,525,465; 5,541,313; 5,545,730; 5,552,538; 5,578,717, 5,580,731; 5,580,731; 5,591,584; 5,109,124; 5,118,802; 5,138,045; 5,414,077; 5,486,603; 5,512,439; 5,578,718; 5,608,046; 4,587,044; 4,605,735; 4,667,025; 4,762,779; 4,789,737; 4,824,941; 4,835,263; 4,876,335; 4,904,582; 4,958,013; 5,082,830; 5,112,963; 5,214,136; 5,082,830; 5,112,963; 5,214,136; 5,245,022; 5,254,469; 5,258,506; 5,262,536; 5,272,250; 5,292,873; 5,317,098; 5,371,241, 5,391,723; 5,416,203, 5,451,463; 5,510,475; 5,512,667; 5,514,785; 5,565,552; 5,567,810; 5,574,142; 5,585,481; 5,587,371; 5,595,726; 5,597,696; 5,599,923; 5,599,928 and 5,688,941, each of which is herein incorporated by reference.
It is not necessary for all positions in a given compound to be uniformly modified, and in fact more than one of the aforementioned modifications may be incorporated in a single compound or even at a single nucleoside within an oligonucleotide. The present invention also includes antisense compounds which are chimeric compounds. “Chimeric” antisense compounds or “chimeras,” in the context of this invention, are antisense compounds, particularly oligonucleotides, which contain two or more chemically distinct regions, each made up of at least one monomer unit, i.e., a nucleotide in the case of an oligonucleotide compound. These oligonucleotides typically contain at least one region wherein the oligonucleotide is modified so as to confer upon the oligonucleotide increased resistance to nuclease degradation, increased cellular uptake, and/or increased binding affinity for the target nucleic acid. An additional region of the oligonucleotide may serve as a substrate for enzymes capable of cleaving RNA:DNA or RNA:RNA hybrids. By way of example, RNase H is a cellular endonuclease which cleaves the RNA strand of an RNA:DNA duplex. Activation of RNase H, therefore, results in cleavage of the RNA target, thereby greatly enhancing the efficiency of oligonucleotide inhibition of gene expression. Consequently, comparable results can often be obtained with shorter oligonucleotides when chimeric oligonucleotides are used, compared to phosphorothioate deoxyoligonucleotides hybridizing to the same target region. Chimeric antisense compounds of the invention may be formed as composite structures of two or more oligonucleotides, modified oligonucleotides, oligonucleosides and/or oligonucleotide mimetics as described above. Preferred chimeric antisense oligonucleotides incorporate at least one 2′ modified sugar (preferably 2′-O—(CH2)2—O—CH3) at the 3′ terminal to confer nuclease resistance and a region with at least 4 contiguous 2′-H sugars to confer RNase H activity. Such compounds have also been referred to in the art as hybrids or gapmers. Preferred gapmers have a region of 2′ modified sugars (preferably 2′-O—(CH2)2—O—CH3) at the 3′-terminal and at the 5′ terminal separated by at least one region having at least 4 contiguous 2′-H sugars and preferably incorporate phosphorothioate backbone linkages. Representative United States patents that teach the preparation of such hybrid structures include, but are not limited to, U.S. Pat. Nos. 5,013,830; 5,149,797; 5,220,007; 5,256,775; 5,366,878; 5,403,711; 5,491,133; 5,565,350; 5,623,065; 5,652,355; 5,652,356; and 5,700,922, each of which is herein incorporated by reference in its entirety.
The antisense compounds used in accordance with this invention may be conveniently and routinely made through the well-known technique of solid phase synthesis. Equipment for such synthesis is sold by several vendors including, for example, Applied Biosystems (Foster City, Calif.). Any other means for such synthesis known in the art may additionally or alternatively be employed. It is well known to use similar techniques to prepare oligonucleotides such as the phosphorothioates and alkylated derivatives. The compounds of the invention may also be admixed, encapsulated, conjugated or otherwise associated with other molecules, molecule structures or mixtures of compounds, as for example, liposomes, receptor targeted molecules, oral, rectal, topical or other formulations, for assisting in uptake, distribution and/or absorption. Representative United States patents that teach the preparation of such uptake, distribution and/or absorption assisting formulations include, but are not limited to, U.S. Pat. Nos. 5,108,921; 5,354,844; 5,416,016; 5,459,127; 5,521,291; 5,543,158; 5,547,932; 5,583,020; 5,591,721; 4,426,330; 4,534,899; 5,013,556; 5,108,921; 5,213,804; 5,227,170; 5,264,221; 5,356,633; 5,395,619; 5,416,016; 5,417,978; 5,462,854; 5,469,854; 5,512,295; 5,527,528; 5,534,259; 5,543,152; 5,556,948; 5,580,575; and 5,595,756, each of which is herein incorporated by reference.
Other examples of sense or antisense oligonucleotides include those oligonucleotides which are covalently linked to organic moieties, such as those described in WO 90/10048, and other moieties that increases affinity of the oligonucleotide for a target nucleic acid sequence, such as poly-(L-lysine). Further still, intercalating agents, such as ellipticine, and alkylating agents or metal complexes may be attached to sense or antisense oligonucleotides to modify binding specificities of the antisense or sense oligonucleotide for the target nucleotide sequence.
Antisense or sense oligonucleotides may be introduced into a cell containing the target nucleic acid sequence by any gene transfer method, including, for example, CaPO4-mediated DNA transfection, electroporation, or by using gene transfer vectors such as Epstein-Barr virus. In a preferred procedure, an antisense or sense oligonucleotide is inserted into a suitable retroviral vector. A cell containing the target nucleic acid sequence is contacted with the recombinant retroviral vector, either in vivo or ex vivo. Suitable retroviral vectors include, but are not limited to, those derived from the murine retrovirus M-MuLV, N2 (a retrovirus derived from M-MuLV), or the double copy vectors designated DCT5A, DCTSB and DCTSC (see WO 90/13641).
Sense or antisense oligonucleotides also may be introduced into a cell containing the target nucleotide sequence by formation of a conjugate with a ligand binding molecule, as described in WO 91/04753. Suitable ligand binding molecules include, but are not limited to, cell surface receptors, growth factors, other cytokines, or other ligands that bind to cell surface receptors. Preferably, conjugation of the ligand binding molecule does not substantially interfere with the ability of the ligand binding molecule to bind to its corresponding molecule or receptor, or block entry of the sense or antisense oligonucleotide or its conjugated version into the cell.
Alternatively, a sense or an antisense oligonucleotide may be introduced into a cell containing the target nucleic acid sequence by formation of an oligonucleotide-lipid complex, as described in WO 90/10448. The sense or antisense oligonucleotide-lipid complex is preferably dissociated within the cell by an endogenous lipase.
Antisense or sense RNA or DNA molecules are generally at least about 5 nucleotides in length, alternatively at least about 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990, or 1000 nucleotides in length, wherein in this context the term “about” means the referenced nucleotide sequence length plus or minus 10% of that referenced length.
The probes may also be employed in PCR techniques to generate a pool of sequences for identification of closely related TAHO coding sequences.
Nucleotide sequences encoding a TAHO can also be used to construct hybridization probes for mapping the gene which encodes that TAHO and for the genetic analysis of individuals with genetic disorders. The nucleotide sequences provided herein may be mapped to a chromosome and specific regions of a chromosome using known techniques, such as in situ hybridization, linkage analysis against known chromosomal markers, and hybridization screening with libraries.
When the coding sequences for TAHO encode a protein which binds to another protein (example, where the TAHO is a receptor), the TAHO can be used in assays to identify the other proteins or molecules involved in the binding interaction. By such methods, inhibitors of the receptor/ligand binding interaction can be identified. Proteins involved in such binding interactions can also be used to screen for peptide or small molecule inhibitors or agonists of the binding interaction. Also, the receptor TAHO can be used to isolate correlative ligand(s). Screening assays can be designed to find lead compounds that mimic the biological activity of a native TAHO or a receptor for TAHO. Such screening assays will include assays amenable to high-throughput screening of chemical libraries, making them particularly suitable for identifying small molecule drug candidates. Small molecules contemplated include synthetic organic or inorganic compounds. The assays can be performed in a variety of formats, including protein-protein binding assays, biochemical screening assays, immunoassays and cell based assays, which are well characterized in the art.
Nucleic acids which encode TAHO or its modified forms can also be used to generate either transgenic animals or “knock out” animals which, in turn, are useful in the development and screening of therapeutically useful reagents. A transgenic animal (e.g., a mouse or rat) is an animal having cells that contain a transgene, which transgene was introduced into the animal or an ancestor of the animal at a prenatal, e.g., an embryonic stage. A transgene is a DNA which is integrated into the genome of a cell from which a transgenic animal develops. In one embodiment, cDNA encoding TAHO can be used to clone genomic DNA encoding TAHO in accordance with established techniques and the genomic sequences used to generate transgenic animals that contain cells which express DNA encoding TAHO. Methods for generating transgenic animals, particularly animals such as mice or rats, have become conventional in the art and are described, for example, in U.S. Pat. Nos. 4,736,866 and 4,870,009. Typically, particular cells would be targeted for TAHO transgene incorporation with tissue-specific enhancers. Transgenic animals that include a copy of a transgene encoding TAHO introduced into the germ line of the animal at an embryonic stage can be used to examine the effect of increased expression of DNA encoding TAHO. Such animals can be used as tester animals for reagents thought to confer protection from, for example, pathological conditions associated with its overexpression. In accordance with this facet of the invention, an animal is treated with the reagent and a reduced incidence of the pathological condition, compared to untreated animals bearing the transgene, would indicate a potential therapeutic intervention for the pathological condition.
Alternatively, non-human homologues of TAHO can be used to construct a TAHO “knock out” animal which has a defective or altered gene encoding TAHO as a result of homologous recombination between the endogenous gene encoding TAHO and altered genomic DNA encoding TAHO introduced into an embryonic stem cell of the animal. For example, cDNA encoding TAHO can be used to clone genomic DNA encoding TAHO in accordance with established techniques. A portion of the genomic DNA encoding TAHO can be deleted or replaced with another gene, such as a gene encoding a selectable marker which can be used to monitor integration. Typically, several kilobases of unaltered flanking DNA (both at the 5′ and 3′ ends) are included in the vector [see e.g., Thomas and Capecchi, Cell, 51:503 (1987) for a description of homologous recombination vectors]. The vector is introduced into an embryonic stem cell line (e.g., by electroporation) and cells in which the introduced DNA has homologously recombined with the endogenous DNA are selected [see e.g., Li et al., Cell, 69:915 (1992)]. The selected cells are then injected into a blastocyst of an animal (e.g., a mouse or rat) to form aggregation chimeras [see e.g., Bradley, in Teratocarcinomas and Embryonic Stem Cells: A Practical Approach, E. J. Robertson, ed. (IRL, Oxford, 1987), pp. 113-152]. A chimeric embryo can then be implanted into a suitable pseudopregnant female foster animal and the embryo brought to term to create a “knock out” animal. Progeny harboring the homologously recombined DNA in their germ cells can be identified by standard techniques and used to breed animals in which all cells of the animal contain the homologously recombined DNA. Knockout animals can be characterized for instance, for their ability to defend against certain pathological conditions and for their development of pathological conditions due to absence of the TAHO polypeptide.
Nucleic acid encoding the TAHO polypeptides may also be used in gene therapy. In gene therapy applications, genes are introduced into cells in order to achieve in vivo synthesis of a therapeutically effective genetic product, for example for replacement of a defective gene. “Gene therapy” includes both conventional gene therapy where a lasting effect is achieved by a single treatment, and the administration of gene therapeutic agents, which involves the one time or repeated administration of a therapeutically effective DNA or mRNA. Antisense RNAs and DNAs can be used as therapeutic agents for blocking the expression of certain genes in vivo. It has already been shown that short antisense oligonucleotides can be imported into cells where they act as inhibitors, despite their low intracellular concentrations caused by their restricted uptake by the cell membrane. (Zamecnik et al., Proc. Natl. Acad. Sci. USA 83:4143-4146 [1986]). The oligonucleotides can be modified to enhance their uptake, e.g. by substituting their negatively charged phosphodiester groups by uncharged groups.
There are a variety of techniques available for introducing nucleic acids into viable cells. The techniques vary depending upon whether the nucleic acid is transferred into cultured cells in vitro, or in vivo in the cells of the intended host. Techniques suitable for the transfer of nucleic acid into mammalian cells in vitro include the use of liposomes, electroporation, microinjection, cell fusion, DEAE-dextran, the calcium phosphate precipitation method, etc. The currently preferred in vivo gene transfer techniques include transfection with viral (typically retroviral) vectors and viral coat protein-liposome mediated transfection (Dzau et al., Trends in Biotechnology 11, 205-210 [1993]). In some situations it is desirable to provide the nucleic acid source with an agent that targets the target cells, such as an antibody specific for a cell surface membrane protein or the target cell, a ligand for a receptor on the target cell, etc. Where liposomes are employed, proteins which bind to a cell surface membrane protein associated with endocytosis may be used for targeting and/or to facilitate uptake, e.g. capsid proteins or fragments thereof tropic for a particular cell type, antibodies for proteins which undergo internalization in cycling, proteins that target intracellular localization and enhance intracellular half-life. The technique of receptor-mediated endocytosis is described, for example, by Wu et al., J. Biol. Chem. 262, 4429-4432 (1987); and Wagner et al., Proc. Natl. Acad. Sci. USA 87, 3410-3414 (1990). For review of gene marking and gene therapy protocols see Anderson et al., Science 256, 808-813 (1992).
The nucleic acid molecules encoding the TAHO polypeptides or fragments thereof described herein are useful for chromosome identification. In this regard, there exists an ongoing need to identify new chromosome markers, since relatively few chromosome marking reagents, based upon actual sequence data are presently available. Each TAHO nucleic acid molecule of the present invention can be used as a chromosome marker.
The TAHO polypeptides and nucleic acid molecules of the present invention may also be used diagnostically for tissue typing, wherein the TAHO polypeptides of the present invention may be differentially expressed in one tissue as compared to another, preferably in a diseased tissue as compared to a normal tissue of the same tissue type. TAHO nucleic acid molecules will find use for generating probes for PCR, Northern analysis, Southern analysis and Western analysis.
This invention encompasses methods of screening compounds to identify those that mimic the TAHO polypeptide (agonists) or prevent the effect of the TAHO polypeptide (antagonists). Screening assays for antagonist drug candidates are designed to identify compounds that bind or complex with the TAHO polypeptides encoded by the genes identified herein, or otherwise interfere with the interaction of the encoded polypeptides with other cellular proteins, including e.g., inhibiting the expression of TAHO polypeptide from cells. Such screening assays will include assays amenable to high-throughput screening of chemical libraries, making them particularly suitable for identifying small molecule drug candidates.
The assays can be performed in a variety of formats, including protein-protein binding assays, biochemical screening assays, immunoassays, and cell-based assays, which are well characterized in the art.
All assays for antagonists are common in that they call for contacting the drug candidate with a TAHO polypeptide encoded by a nucleic acid identified herein under conditions and for a time sufficient to allow these two components to interact.
In binding assays, the interaction is binding and the complex formed can be isolated or detected in the reaction mixture. In a particular embodiment, the TAHO polypeptide encoded by the gene identified herein or the drug candidate is immobilized on a solid phase, e.g., on a microtiter plate, by covalent or non-covalent attachments. Non-covalent attachment generally is accomplished by coating the solid surface with a solution of the TAHO polypeptide and drying. Alternatively, an immobilized antibody, e.g., a monoclonal antibody, specific for the TAHO polypeptide to be immobilized can be used to anchor it to a solid surface. The assay is performed by adding the non-immobilized component, which may be labeled by a detectable label, to the immobilized component, e.g., the coated surface containing the anchored component. When the reaction is complete, the non-reacted components are removed, e.g., by washing, and complexes anchored on the solid surface are detected. When the originally non-immobilized component carries a detectable label, the detection of label immobilized on the surface indicates that complexing occurred. Where the originally non-immobilized component does not carry a label, complexing can be detected, for example, by using a labeled antibody specifically binding the immobilized complex.
If the candidate compound interacts with but does not bind to a particular TAHO polypeptide encoded by a gene identified herein, its interaction with that polypeptide can be assayed by methods well known for detecting protein-protein interactions. Such assays include traditional approaches, such as, e.g., cross-linking, co-immunoprecipitation, and co-purification through gradients or chromatographic columns. In addition, protein-protein interactions can be monitored by using a yeast-based genetic system described by Fields and co-workers (Fields and Song, Nature (London), 340:245-246 (1989); Chien et al., Proc. Natl. Acad. Sci. USA, 88:9578-9582 (1991)) as disclosed by Chevray and Nathans, Proc. Natl. Acad. Sci. USA, 89: 5789-5793 (1991). Many transcriptional activators, such as yeast GAL4, consist of two physically discrete modular domains, one acting as the DNA-binding domain, the other one functioning as the transcription-activation domain. The yeast expression system described in the foregoing publications (generally referred to as the “two-hybrid system”) takes advantage of this property, and employs two hybrid proteins, one in which the target protein is fused to the DNA-binding domain of GAL4, and another, in which candidate activating proteins are fused to the activation domain. The expression of a GAL1-lacZ reporter gene under control of a GAL4-activated promoter depends on reconstitution of GAL4 activity via protein-protein interaction. Colonies containing interacting polypeptides are detected with a chromogenic substrate for β-galactosidase. A complete kit (MATCHMAKER™) for identifying protein-protein interactions between two specific proteins using the two-hybrid technique is commercially available from Clontech. This system can also be extended to map protein domains involved in specific protein interactions as well as to pinpoint amino acid residues that are crucial for these interactions.
Compounds that interfere with the interaction of a gene encoding a TAHO polypeptide identified, herein and other intra- or extracellular components can be tested as follows: usually a reaction mixture is prepared containing the product of the gene and the intra- or extracellular component under conditions and for a time allowing for the interaction and binding of the two products. To test the ability of a candidate compound to inhibit binding, the reaction is run in the absence and in the presence of the test compound. In addition, a placebo may be added to a third reaction mixture, to serve as positive control. The binding (complex formation) between the test compound and the intra- or extracellular component present in the mixture is monitored as described hereinabove. The formation of a complex in the control reaction(s) but not in the reaction mixture containing the test compound indicates that the test compound interferes with the interaction of the test compound and its reaction partner.
To assay for antagonists, the TAHO polypeptide may be added to a cell along with the compound to be screened for a particular activity and the ability of the compound to inhibit the activity of interest in the presence of the TAHO polypeptide indicates that the compound is an antagonist to the TAHO polypeptide. Alternatively, antagonists may be detected by combining the TAHO polypeptide and a potential antagonist with membrane-bound TAHO polypeptide receptors or recombinant receptors under appropriate conditions for a competitive inhibition assay. The TAHO polypeptide can be labeled, such as by radioactivity, such that the number of TAHO polypeptide molecules bound to the receptor can be used to determine the effectiveness of the potential antagonist. The gene encoding the receptor can be identified by numerous methods known to those of skill in the art, for example, ligand panning and FACS sorting. Coligan et al., Current Protocols in Immun., 1(2): Chapter 5 (1991). Preferably, expression cloning is employed wherein polyadenylated RNA is prepared from a cell responsive to the TAHO polypeptide and a cDNA library created from this RNA is divided into pools and used to transfect COS cells or other cells that are not responsive to the TAHO polypeptide. Transfected cells that are grown on glass slides are exposed to labeled TAHO polypeptide. The TAHO polypeptide can be labeled by a variety of means including iodination or inclusion of a recognition site for a site-specific protein kinase. Following fixation and incubation, the slides are subjected to autoradiographic analysis. Positive pools are identified and sub-pools are prepared and re-transfected using an interactive sub-pooling and re-screening process, eventually yielding a single clone that encodes the putative receptor.
As an alternative approach for receptor identification, labeled TAHO polypeptide can be photoaffinity-linked with cell membrane or extract preparations that express the receptor molecule. Cross-linked material is resolved by PAGE and exposed to X-ray film. The labeled complex containing the receptor can be excised, resolved into peptide fragments, and subjected to protein micro-sequencing. The amino acid sequence obtained from micro-sequencing would be used to design a set of degenerate oligonucleotide probes to screen a cDNA library to identify the gene encoding the putative receptor.
In another assay for antagonists, mammalian cells or a membrane preparation expressing the receptor would be incubated with labeled TAHO polypeptide in the presence of the candidate compound. The ability of the compound to enhance or block this interaction could then be measured.
More specific examples of potential antagonists include an oligonucleotide that binds to the fusions of immunoglobulin with TAHO polypeptide, and, in particular, antibodies including, without limitation, poly- and monoclonal antibodies and antibody fragments, single-chain antibodies, anti-idiotypic antibodies, and chimeric or humanized versions of such antibodies or fragments, as well as human antibodies and antibody fragments. Alternatively, a potential antagonist may be a closely related protein, for example, a mutated form of the TAHO polypeptide that recognizes the receptor but imparts no effect, thereby competitively inhibiting the action of the TAHO polypeptide.
Another potential TAHO polypeptide antagonist is an antisense RNA or DNA construct prepared using antisense technology, where, e.g., an antisense RNA or DNA molecule acts to block directly the translation of mRNA by hybridizing to targeted mRNA and preventing protein translation. Antisense technology can be used to control gene expression through triple-helix formation or antisense DNA or RNA, both of which methods are based on binding of a polynucleotide to DNA or RNA. For example, the 5′ coding portion of the polynucleotide sequence, which encodes the mature TAHO polypeptides herein, is used to design an antisense RNA oligonucleotide of from about 10 to 40 base pairs in length. A DNA oligonucleotide is designed to be complementary to a region of the gene involved in transcription (triple helix—see Lee et al., Nucl. Acids Res., 6:3073 (1979); Cooney et al., Science, 241: 456 (1988); Dervan et al., Science, 251:1360 (1991)), thereby preventing transcription and the production of the TAHO polypeptide. The antisense RNA oligonucleotide hybridizes to the mRNA in vivo and blocks translation of the mRNA molecule into the TAHO polypeptide (antisense—Okano, Neurochem., 56:560 (1991); Oligodeoxynucleotides as Antisense Inhibitors of Gene Expression (CRC Press: Boca Raton, Fla., 1988). The oligonucleotides described above can also be delivered to cells such that the antisense RNA or DNA may be expressed in vivo to inhibit production of the TAHO polypeptide. When antisense DNA is used, oligodeoxyribonucleotides derived from the translation-initiation site, e.g., between about −10 and +10 positions of the target gene nucleotide sequence, are preferred.
Potential antagonists include small molecules that bind to the active site, the receptor binding site, or growth factor or other relevant binding site of the TAHO polypeptide, thereby blocking the normal biological activity of the TAHO polypeptide. Examples of small molecules include, but are not limited to, small peptides or peptide-like molecules, preferably soluble peptides, and synthetic non-peptidyl organic or inorganic compounds.
Ribozymes are enzymatic RNA molecules capable of catalyzing the specific cleavage of RNA. Ribozymes act by sequence-specific hybridization to the complementary target RNA, followed by endonucleolytic cleavage. Specific ribozyme cleavage sites within a potential RNA target can be identified by known techniques. For further details see, e.g., Rossi, Current Biology, 4:469-471 (1994), and PCT publication No. WO 97/33551 (published Sep. 18, 1997).
Nucleic acid molecules in triple-helix formation used to inhibit transcription should be single-stranded and composed of deoxynucleotides. The base composition of these oligonucleotides is designed such that it promotes triple-helix formation via Hoogsteen base-pairing rules, which generally require sizeable stretches of purines or pyrimidines on one strand of a duplex. For further details see, e.g., PCT publication No. WO 97/33551, supra.
These small molecules can be identified by any one or more of the screening assays discussed hereinabove and/or by any other screening techniques well known for those skilled in the art.
Isolated TAHO polypeptide-encoding nucleic acid can be used herein for recombinantly producing TAHO polypeptide using techniques well known in the art and as described herein. In turn, the produced TAHO polypeptides can be employed for generating anti-TAHO antibodies using techniques well known in the art and as described herein.
Antibodies specifically binding a TAHO polypeptide identified herein, as well as other molecules identified by the screening assays disclosed hereinbefore, can be administered for the treatment of various disorders, including cancer, in the form of pharmaceutical compositions.
If the TAHO polypeptide is intracellular and whole antibodies are used as inhibitors, internalizing antibodies are preferred. However, lipofections or liposomes can also be used to deliver the antibody, or an antibody fragment, into cells. Where antibody fragments are used, the smallest inhibitory fragment that specifically binds to the binding domain of the target protein is preferred. For example, based upon the variable-region sequences of an antibody, peptide molecules can be designed that retain the ability to bind the target protein sequence. Such peptides can be synthesized chemically and/or produced by recombinant DNA technology. See, e.g., Marasco et al., Proc. Natl. Acad. Sci. USA, 90: 7889-7893 (1993).
The formulation herein may also contain more than one active compound as necessary for the particular indication being treated, preferably those with complementary activities that do not adversely affect each other. Alternatively, or in addition, the composition may comprise an agent that enhances its function, such as, for example, a cytotoxic agent, cytokine, chemotherapeutic agent, or growth-inhibitory agent. Such molecules are suitably present in combination in amounts that are effective for the purpose intended.
P. Antibody Derivatives
The antibodies of the present invention can be further modified to contain additional nonproteinaceous moieties that are known in the art and readily available. Preferably, the moieties suitable for derivatization of the antibody are water soluble polymers. Non-limiting examples of water soluble polymers include, but are not limited to, polyethylene glycol (PEG), copolymers of ethylene glycol/propylene glycol, carboxymethylcellulose, dextran, polyvinyl alcohol, polyvinyl pyrrolidone, poly-1,3-dioxolane, poly-1,3,6-trioxane, ethylene/maleic anhydride copolymer, polyaminoacids (either homopolymers or random copolymers), and dextran or poly(n-vinyl pyrrolidone)polyethylene glycol, propropylene glycol homopolymers, prolypropylene oxide/ethylene oxide co-polymers, polyoxyethylated polyols (e.g., glycerol), polyvinyl alcohol, and mixtures thereof. Polyethylene glycol propionaldehyde may have advantages in manufacturing due to its stability in water. The polymer may be of any molecular weight, and may be branched or unbranched. The number of polymers attached to the antibody may vary, and if more than one polymers are attached, they can be the same or different molecules. In general, the number and/or type of polymers used for derivatization can be determined based on considerations including, but not limited to, the particular properties or functions of the antibody to be improved, whether the antibody derivative will be used in a therapy under defined conditions, etc.
Q. Method of Screening
Yet another embodiment of the present invention is directed to a method of determining the presence of a TAHO polypeptide in a sample suspected of containing the TAHO polypeptide, wherein the method comprises exposing the sample to an antibody drug conjugate thereof, that binds to the TAHO polypeptide and determining binding of the antibody drug conjugate thereof, to the TAHO polypeptide in the sample, wherein the presence of such binding is indicative of the presence of the TAHO polypeptide in the sample. Optionally, the sample may contain cells (which may be cancer cells) suspected of expressing the TAHO polypeptide. The antibody drug conjugate thereof, employed in the method may optionally be detectably labeled, attached to a solid support, or the like.
Another embodiment of the present invention is directed to a method of diagnosing the presence of a tumor in a mammal, wherein the method comprises (a) contacting a test sample comprising tissue cells obtained from the mammal with an antibody drug conjugate thereof, that binds to a TAHO polypeptide and (b) detecting the formation of a complex between the antibody drug conjugate thereof, and the TAHO polypeptide in the test sample, wherein the formation of a complex is indicative of the presence of a tumor in the mammal. Optionally, the antibody drug conjugate thereof, is detectably labeled, attached to a solid support, or the like, and/or the test sample of tissue cells is obtained from an individual suspected of having a cancerous tumor.
A. Diagnostic Methods and Methods of Detection
In one aspect, anti-TAHO antibodies and immunoconjugates of the invention are useful for detecting the presence of a TAHO polypeptide in a biological sample. The term “detecting” as used herein encompasses quantitative or qualitative detection. In certain embodiments, a biological sample comprises a cell or tissue. In certain embodiments, such tissues include normal and/or cancerous tissues that express a TAHO polypeptide at higher levels relative to other tissues, for example, B cells and/or B cell associated tissues.
In one aspect, the invention provides a method of detecting the presence of a TAHO polypeptide in a biological sample. In certain embodiments, the method comprises contacting the biological sample with an anti-TAHO antibody under conditions permissive for binding of the anti-TAHO antibody to a TAHO polypeptide, and detecting whether a complex is formed between the anti-TAHO antibody and a TAHO polypeptide.
In one aspect, the invention provides a method of diagnosing a disorder associated with increased expression of a TAHO polypeptide. In certain embodiments, the method comprises contacting a test cell with an anti-TAHO antibody; determining the level of expression (either quantitatively or qualitatively) of a TAHO polypeptide by the test cell by detecting binding of the anti-TAHO antibody to a TAHO polypeptide; and comparing the level of expression of a TAHO polypeptide by the test cell with the level of expression of a TAHO polypeptide by a control cell (e.g., a normal cell of the same tissue origin as the test cell or a cell that expresses a TAHO polypeptide at levels comparable to such a normal cell), wherein a higher level of expression of a TAHO polypeptide by the test cell as compared to the control cell indicates the presence of a disorder associated with increased expression of a TAHO polypeptide. In certain embodiments, the test cell is obtained from an individual suspected of having a disorder associated with increased expression of a TAHO polypeptide. In certain embodiments, the disorder is a cell proliferative disorder, such as a cancer or a tumor.
Exemplary cell proliferative disorders that may be diagnosed using an antibody of the invention include a B cell disorder and/or a B cell proliferative disorder including, but not limited to, lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In certain embodiments, a method of diagnosis or detection, such as those described above, comprises detecting binding of an anti-TAHO antibody to a TAHO polypeptide expressed on the surface of a cell or in a membrane preparation obtained from a cell expressing a TAHO polypeptide on its surface. In certain embodiments, the method comprises contacting a cell with an anti-TAHO antibody under conditions permissive for binding of the anti-TAHO antibody to a TAHO polypeptide, and detecting whether a complex is formed between the anti-TAHO antibody and a TAHO polypeptide on the cell surface. An exemplary assay for detecting binding of an anti-TAHO antibody to a TAHO polypeptide expressed on the surface of a cell is a “FACS” assay.
Certain other methods can be used to detect binding of anti-TAHO antibodies to a TAHO polypeptide. Such methods include, but are not limited to, antigen-binding assays that are well known in the art, such as western blots, radioimmunoassays, ELISA (enzyme linked immunosorbent assay), “sandwich” immunoassays, immunoprecipitation assays, fluorescent immunoassays, protein A immunoassays, and immunohistochemistry (IHC).
In certain embodiments, anti-TAHO antibodies are labeled. Labels include, but are not limited to, labels or moieties that are detected directly (such as fluorescent, chromophoric, electron-dense, chemiluminescent, and radioactive labels), as well as moieties, such as enzymes or ligands, that are detected indirectly, e.g., through an enzymatic reaction or molecular interaction. Exemplary labels include, but are not limited to, the radioisotopes 32P, 14C, 125I, 3H, and 131I, fluorophores such as rare earth chelates or fluorescein and its derivatives, rhodamine and its derivatives, dansyl, umbelliferone, luceriferases, e.g., firefly luciferase and bacterial luciferase (U.S. Pat. No. 4,737,456), luciferin, 2,3-dihydrophthalazinediones, horseradish peroxidase (HRP), alkaline phosphatase, β-galactosidase, glucoamylase, lysozyme, saccharide oxidases, e.g., glucose oxidase, galactose oxidase, and glucose-6-phosphate dehydrogenase, heterocyclic oxidases such as uricase and xanthine oxidase, coupled with an enzyme that employs hydrogen peroxide to oxidize a dye precursor such as HRP, lactoperoxidase, or microperoxidase, biotin/avidin, spin labels, bacteriophage labels, stable free radicals, and the like.
In certain embodiments, anti-TAHO antibodies are immobilized on an insoluble matrix. Immobilization entails separating the anti-TAHO antibody from any a TAHO polypeptide that remains free in solution. This conventionally is accomplished by either insolubilizing the anti-TAHO antibody before the assay procedure, as by adsorption to a water-insoluble matrix or surface (Bennich et al., U.S. Pat. No. 3,720,760), or by covalent coupling (for example, using glutaraldehyde cross-linking), or by insolubilizing the anti-TAHO antibody after formation of a complex between the anti-TAHO antibody and a TAHO polypeptide, e.g., by immunoprecipitation.
Any of the above embodiments of diagnosis or detection may be carried out using an immunoconjugate of the invention in place of or in addition to an anti-TAHO antibody.
B. Therapeutic Methods
An antibody or immunoconjugate of the invention may be used in, for example, in vitro, ex vivo, and in vivo therapeutic methods. In one aspect, the invention provides methods for inhibiting cell growth or proliferation, either in vivo or in vitro, the method comprising exposing a cell to an anti-TAHO antibody or immunoconjugate thereof under conditions permissive for binding of the immunoconjugate to a TAHO polypeptide. “Inhibiting cell growth or proliferation” means decreasing a cell's growth or proliferation by at least 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, or 100%, and includes inducing cell death. In certain embodiments, the cell is a tumor cell. In certain embodiments, the cell is a B cell. In certain embodiments, the cell is a xenograft, e.g., as exemplified herein.
In one aspect, an antibody or immunoconjugate of the invention is used to treat or prevent a B cell proliferative disorder. In certain embodiments, the cell proliferative disorder is associated with increased expression and/or activity of a TAHO polypeptide. For example, in certain embodiments, the B cell proliferative disorder is associated with increased expression of a TAHO polypeptide on the surface of a B cell. In certain embodiments, the B cell proliferative disorder is a tumor or a cancer. Examples of B cell proliferative disorders to be treated by the antibodies or immunoconjugates of the invention include, but are not limited to, lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
In one aspect, the invention provides methods for treating a B cell proliferative disorder comprising administering to an individual an effective amount of an anti-TAHO antibody or immunoconjugate thereof. In certain embodiments, a method for treating a B cell proliferative disorder comprises administering to an individual an effective amount of a pharmaceutical formulation comprising an anti-TAHO antibody or anti-TAHO immunoconjugate and, optionally, at least one additional therapeutic agent, such as those provided below. In certain embodiments, a method for treating a cell proliferative disorder comprises administering to an individual an effective amount of a pharmaceutical formulation comprising 1) an immunoconjugate comprising an anti-TAHO antibody and a cytotoxic agent; and optionally, 2) at least one additional therapeutic agent, such as those provided below.
In one aspect, at least some of the antibodies or immunoconjugates of the invention can bind a TAHO polypeptide from species other than human. Accordingly, antibodies or immunoconjugates of the invention can be used to bind a TAHO polypeptide, e.g., in a cell culture containing a TAHO polypeptide, in humans, or in other mammals having a TAHO polypeptide with which an antibody or immunoconjugate of the invention cross-reacts (e.g. chimpanzee, baboon, marmoset, cynomolgus and rhesus monkeys, pig or mouse). In one embodiment, an anti-TAHO antibody or immunoconjugate can be used for targeting a TAHO polypeptide on B cells by contacting the antibody or immunoconjugate with a TAHO polypeptide to form an antibody or immunoconjugate-antigen complex such that a conjugated cytotoxin of the immunoconjugate accesses the interior of the cell. In one embodiment, the TAHO polypeptide is a human TAHO polypeptide.
In one embodiment, an anti-TAHO antibody or immunoconjugate can be used in a method for binding a TAHO polypeptide in an individual suffering from a disorder associated with increased TAHO polypeptide expression and/or activity, the method comprising administering to the individual the antibody or immunoconjugate such that a TAHO polypeptide in the individual is bound. In one embodiment, the bound antibody or immunoconjugate is internalized into the B cell expressing a TAHO polypeptide. In one embodiment, the TAHO polypeptide is a human TAHO polypeptide, and the individual is a human individual. Alternatively, the individual can be a mammal expressing a TAHO polypeptide to which an anti-TAHO antibody binds. Still further the individual can be a mammal into which a TAHO polypeptide has been introduced (e.g., by administration of a TAHO polypeptide or by expression of a transgene encoding a TAHO polypeptide).
An anti-TAHO antibody or immunoconjugate can be administered to a human for therapeutic purposes. Moreover, an anti-TAHO antibody or immunoconjugate can be administered to a non-human mammal expressing a TAHO polypeptide with which the antibody cross-reacts (e.g., a primate, pig, rat, or mouse) for veterinary purposes or as an animal model of human disease. Regarding the latter, such animal models may be useful for evaluating the therapeutic efficacy of antibodies or immunoconjugates of the invention (e.g., testing of dosages and time courses of administration).
Antibodies or immunoconjugates of the invention can be used either alone or in combination with other compositions in a therapy. For instance, an antibody or immunoconjugate of the invention may be co-administered with at least one additional therapeutic agent and/or adjuvant. In certain embodiments, an additional therapeutic agent is a cytotoxic agent, a chemotherapeutic agent, or a growth inhibitory agent. In one of such embodiments, a chemotherapeutic agent is an agent or a combination of agents such as, for example, cyclophosphamide, hydroxydaunorubicin, adriamycin, doxorubincin, vincristine (Oncovin™), prednisolone, CHOP, CVP, or COP, or immunotherapeutics such as anti-CD20 (e.g., Rituxan®) or anti-VEGF (e.g., Avastin®), wherein the combination therapy is useful in the treatment of cancers and/or B cell disorders such as B cell proliferative disorders including lymphoma, non-Hodgkins lymphoma (NHL), aggressive NHL, relapsed aggressive NHL, relapsed indolent NHL, refractory NHL, refractory indolent NHL, chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma, leukemia, hairy cell leukemia (HCL), acute lymphocytic leukemia (ALL), and mantle cell lymphoma.
Such combination therapies noted above encompass combined administration (where two or more therapeutic agents are included in the same or separate formulations), and separate administration, in which case, administration of the antibody or immunoconjugate of the invention can occur prior to, simultaneously, and/or following, administration of the additional therapeutic agent and/or adjuvant. Antibodies or immunoconjugates of the invention can also be used in combination with radiation therapy.
An antibody or immunoconjugate of the invention (and any additional therapeutic agent or adjuvant) cAn be administered by any suitable means, including parenteral, subcutaneous, intraperitoneal, intrapulmonary, and intranasal, and, if desired for local treatment, intralesional administration. Parenteral infusions include intramuscular, intravenous, intraarterial, intraperitoneal, or subcutaneous administration. In addition, the antibody or immunoconjugate is suitably administered by pulse infusion, particularly with declining doses of the antibody or immunoconjugate. Dosing can be by any suitable route, e.g. by injections, such as intravenous or subcutaneous injections, depending in part on whether the administration is brief or chronic.
Antibodies or immunoconjugates of the invention would be formulated, dosed, and administered in a fashion consistent with good medical practice. Factors for consideration in this context include the particular disorder being treated, the particular mammal being treated, the clinical condition of the individual patient, the cause of the disorder, the site of delivery of the agent, the method of administration, the scheduling of administration, and other factors known to medical practitioners. The antibody or immunoconjugate need not be, but is optionally formulated with one or more agents currently used to prevent or treat the disorder in question. The effective amount of such other agents depends on the amount of antibody or immunoconjugate present in the formulation, the type of disorder or treatment, and other factors discussed above. These are generally used in the same dosages and with administration routes as described herein, or about from 1 to 99% of the dosages described herein, or in any dosage and by any route that is empirically/clinically determined to be appropriate.
For the prevention or treatment of disease, the appropriate dosage of an antibody or immunoconjugate of the invention (when used alone or in combination with one or more other additional therapeutic agents, such as chemotherapeutic agents) will depend on the type of disease to be treated, the type of antibody or immunoconjugate, the severity and course of the disease, whether the antibody or immunoconjugate is administered for preventive or therapeutic purposes, previous therapy, the patient's clinical history and response to the antibody or immunoconjugate, and the discretion of the attending physician. The antibody or immunoconjugate is suitably administered to the patient at one time or over a series of treatments. Depending on the type and severity of the disease, about 1 μg/kg to 100 mg/kg (e.g. 0.1 mg/kg-20 mg/kg) of antibody or immunoconjugate can be an initial candidate dosage for administration to the patient, whether, for example, by one or more separate administrations, or by continuous infusion. One typical daily dosage might range from about 1 μg/kg to 100 mg/kg or more, depending on the factors mentioned above. For repeated administrations over several days or longer, depending on the condition, the treatment would generally be sustained until a desired suppression of disease symptoms occurs. One exemplary dosage of the antibody or immunoconjugate would be in the range from about 0.05 mg/kg to about 10 mg/kg. Thus, one or more doses of about 0.5 mg/kg, 2.0 mg/kg, 4.0 mg/kg or 10 mg/kg (or any combination thereof) of antibody or immunoconjugate may be administered to the patient. Such doses may be administered intermittently, e.g. every week or every three weeks (e.g. such that the patient receives from about two to about twenty, or e.g. about six doses of the antibody or immunoconjugate). An initial higher loading dose, followed by one or more lower doses may be administered. An exemplary dosing regimen comprises administering an initial loading dose of about 4 mg/kg, followed by a weekly maintenance dose of about 2 mg/kg of the antibody. However, other dosage regimens may be useful. The progress of this therapy is easily monitored by conventional techniques and assays.
C. Activity Assays
Anti-TAHO antibodies and immunoconjugates of the invention may be characterized for their physical/chemical properties and/or biological activities by various assays known in the art.
1. Activity Assays
In one aspect, assays are provided for identifying anti-TAHO antibodies or immunoconjugates thereof having biological activity. Biological activity may include, e.g., the ability to inhibit cell growth or proliferation (e.g., “cell killing” activity), or the ability to induce cell death, including programmed cell death (apoptosis). Antibodies or immunoconjugates having such biological activity in vivo and/or in vitro are also provided.
In certain embodiments, an anti-TAHO antibody or immunoconjugate thereof is tested for its ability to inhibit cell growth or proliferation in vitro. Assays for inhibition of cell growth or proliferation are well known in the art. Certain assays for cell proliferation, exemplified by the “cell killing” assays described herein, measure cell viability. One such assay is the CellTiter-Glo™ Luminescent Cell Viability Assay, which is commercially available from Promega (Madison, Wis.). That assay determines the number of viable cells in culture based on quantitation of ATP present, which is an indication of metabolically active cells. See Crouch et al (1993) J. Immunol. Meth. 160:81-88, U.S. Pat. No. 6,602,677. The assay may be conducted in 96- or 384-well format, making it amenable to automated high-throughput screening (HTS). See Cree et al (1995) AntiCancer Drugs 6:398-404. The assay procedure involves adding a single reagent (CellTiter-Glo® Reagent) directly to cultured cells. This results in cell lysis and generation of a luminescent signal produced by a luciferase reaction. The luminescent signal is proportional to the amount of ATP present, which is directly proportional to the number of viable cells present in culture. Data can be recorded by luminometer or CCD camera imaging device. The luminescence output is expressed as relative light units (RLU).
Another assay for cell proliferation is the “MTT” assay, a colorimetric assay that measures the oxidation of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide to formazan by mitochondrial reductase. Like the CellTiter-Glo™ assay, this assay indicates the number of metabolically active cells present in a cell culture. See, e.g., Mosmann (1983) J. Immunol. Meth. 65:55-63, and Zhang et al. (2005) Cancer Res. 65:3877-3882.
In one aspect, an anti-TAHO antibody is tested for its ability to induce cell death in vitro. Assays for induction of cell death are well known in the art. In some embodiments, such assays measure, e.g., loss of membrane integrity as indicated by uptake of propidium iodide (PI), trypan blue (see Moore et al. (1995) Cytotechnology, 17:1-11), or 7AAD. In an exemplary PI uptake assay, cells are cultured in Dulbecco's Modified Eagle Medium (D-MEM):Ham's F-12 (50:50) supplemented with 10% heat-inactivated FBS (Hyclone) and 2 mM L-glutamine. Thus, the assay is performed in the absence of complement and immune effector cells. Cells are seeded at a density of 3×106 per dish in 100×20 mm dishes and allowed to attach overnight. The medium is removed and replaced with fresh medium alone or medium containing various concentrations of the antibody or immunoconjugate. The cells are incubated for a 3-day time period. Following treatment, monolayers are washed with PBS and detached by trypsinization. Cells are then centrifuged at 1200 rpm for 5 minutes at 4° C., the pellet resuspended in 3 ml cold Ca2+ binding buffer (10 mM Hepes, pH 7.4, 140 mM NaCl, 2.5 mM CaCl2) and aliquoted into 35 mm strainer-capped 12×75 mm tubes (1 ml per tube, 3 tubes per treatment group) for removal of cell clumps. Tubes then receive PI (10 μg/ml). Samples are analyzed using a FACSCAN™ flow cytometer and FACSCONVERT™ CellQuest software (Becton Dickinson). Antibodies or immunoconjugates which induce statistically significant levels of cell death as determined by PI uptake are thus identified.
In one aspect, an anti-TAHO antibody or immunoconjugate is tested for its ability to induce apoptosis (programmed cell death) in vitro. An exemplary assay for antibodies or immunconjugates that induce apoptosis is an annexin binding assay. In an exemplary annexin binding assay, cells are cultured and seeded in dishes as discussed in the preceding paragraph. The medium is removed and replaced with fresh medium alone or medium containing 0.001 to 10 μg/ml of the antibody or immunoconjugate. Following a three-day incubation period, monolayers are washed with PBS and detached by trypsinization. Cells are then centrifuged, resuspended in Ca2+ binding buffer, and aliquoted into tubes as discussed in the preceding paragraph. Tubes then receive labeled annexin (e.g. annexin V-FITC) (1 μg/ml). Samples are analyzed using a FACSCAN™ flow cytometer and FACSCONVERT™ CellQuest software (BD Biosciences). Antibodies or immunoconjugates that induce statistically significant levels of annexin binding relative to control are thus identified. Another exemplary assay for antibodies or immunconjugates that induce apoptosis is a histone DNA ELISA colorimetric assay for detecting internucleosomal degradation of genomic DNA. Such an assay can be performed using, e.g., the Cell Death Detection ELISA kit (Roche, Palo Alto, Calif.).
Cells for use in any of the above in vitro assays include cells or cell lines that naturally express a TAHO polypeptide or that have been engineered to express a TAHO polypeptide. Such cells include tumor cells that overexpress a TAHO polypeptide relative to normal cells of the same tissue origin. Such cells also include cell lines (including tumor cell lines) that express a TAHO polypeptide and cell lines that do not normally express a TAHO polypeptide but have been transfected with nucleic acid encoding a TAHO polypeptide.
In one aspect, an anti-TAHO antibody or immunoconjugate thereof is tested for its ability to inhibit cell growth or proliferation in vivo. In certain embodiments, an anti-TAHO antibody or immunoconjugate thereof is tested for its ability to inhibit tumor growth in vivo. In vivo model systems, such as xenograft models, can be used for such testing. In an exemplary xenograft system, human tumor cells are introduced into a suitably immunocompromised non-human animal, e.g., a SCID mouse. An antibody or immunoconjugate of the invention is administered to the animal. The ability of the antibody or immunoconjugate to inhibit or decrease tumor growth is measured. In certain embodiments of the above xenograft system, the human tumor cells are tumor cells from a human patient. Such cells useful for preparing xenograft models include human leukemia and lymphoma cell lines, which include without limitation the BJAB-luc cells (an EBV-negative Burkitt's lymphoma cell line transfected with the luciferase reporter gene), Ramos cells (ATCC, Manassas, Va., CRL-1923), SuDHL-4 cells (DSMZ, Braunschweig, Germany, AAC 495), DoHH2 cells (see Kluin-Neilemans, H. C. et al., Leukemia 5:221-224 (1991), and Kluin-Neilemans, H. C. et al., Leukemia 8:1385-1391 (1994)), Granta-519 cells (see Jadayel, D. M. et al, Leukemia 11(1):64-72 (1997)). In certain embodiments, the human tumor cells are introduced into a suitably immunocompromised non-human animal by subcutaneous injection or by transplantation into a suitable site, such as a mammary fat pad.
2. Binding Assays and Other Assays
In one aspect, an anti-TAHO antibody is tested for its antigen binding activity. For example, in certain embodiments, an anti-TAHO antibody is tested for its ability to bind to a TAHO polypeptide expressed on the surface of a cell. A FACS assay may be used for such testing.
In one aspect, competition assays may be used to identify a monoclonal antibody that competes with murine SN8 antibody for binding to a TAHO polypeptide. In certain embodiments, such a competing antibody binds to the same epitope (e.g., a linear or a conformational epitope) that is bound by murine SN8 antibody. Exemplary competition assays include, but are not limited to, routine assays such as those provided in Harlow and Lane (1988) Antibodies: A Laboratory Manual ch.14 (Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.). Detailed exemplary methods for mapping an epitope to which an antibody binds are provided in Morris (1996) “Epitope Mapping Protocols,” in Methods in Molecular Biology vol. 66 (Humana Press, Totowa, N.J.). Two antibodies are said to bind to the same epitope if each blocks binding of the other by 50% or more.
In an exemplary competition assay, immobilized TAHO polypeptide is incubated in a solution comprising a first labeled antibody that binds to a TAHO polypeptide (e.g., murine SN8 antibody) and a second unlabeled antibody that is being tested for its ability to compete with the first antibody for binding to a TAHO polypeptide. The second antibody may be present in a hybridoma supernatant. As a control, immobilized TAHO polypeptide is incubated in a solution comprising the first labeled antibody but not the second unlabeled antibody. After incubation under conditions permissive for binding of the first antibody to a TAHO polypeptide, excess unbound antibody is removed, and the amount of label associated with immobilized TAHO polypeptide is measured. If the amount of label associated with immobilized TAHO polypeptide is substantially reduced in the test sample relative to the control sample, then that indicates that the second antibody is competing with the first antibody for binding to a TAHO polypeptide. In certain embodiments, immobilized TAHO polypeptide is present on the surface of a cell or in a membrane preparation obtained from a cell expressing a TAHO polypeptide on its surface.
In one aspect, purified anti-TAHO antibodies can be further characterized by a series of assays including, but not limited to, N-terminal sequencing, amino acid analysis, non-denaturing size exclusion high pressure liquid chromatography (HPLC), mass spectrometry, ion exchange chromatography and papain digestion.
In one embodiment, the invention contemplates an altered antibody that possesses some but not all effector functions, which make it a desirable candidate for many applications in which the half life of the antibody in vivo is important yet certain effector functions (such as complement and ADCC) are unnecessary or deleterious. In certain embodiments, the Fc activities of the antibody are measured to ensure that only the desired properties are maintained. In vitro and/or in vivo cytotoxicity assays can be conducted to confirm the reduction/depletion of CDC and/or ADCC activities. For example, Fc receptor (FcR) binding assays can be conducted to ensure that the antibody lacks FcγR binding (hence likely lacking ADCC activity), but retains FcRn binding ability. The primary cells for mediating ADCC, NK cells, express FcγRIII only, whereas monocytes express Fc(RI, Fc(RII and Fc(RIII. FcR expression on hematopoietic cells is summarized in Table 3 on page 464 of Ravetch and Kinet, Annu. Rev. Immunol. 9:457-92 (1991). An example of an in vitro assay to assess ADCC activity of a molecule of interest is described in U.S. Pat. No. 5,500,362 or 5,821,337. Useful effector cells for such assays include peripheral blood mononuclear cells (PBMC) and Natural Killer (NK) cells. Alternatively, or additionally, ADCC activity of the molecule of interest may be assessed in vivo, e.g., in a animal model such as that disclosed in Clynes et al. PNAS (USA) 95:652-656 (1998). C1q binding assays may also be carried out to confirm that the antibody is unable to bind C1q and hence lacks CDC activity. To assess complement activation, a CDC assay, e.g. as described in Gazzano-Santoro et al., J. Immunol. Methods 202:163 (1996), may be performed. FcRn binding and in vivo clearance/half life determinations can also be performed using methods known in the art.
The following examples are offered for illustrative purposes only, and are not intended to limit the scope of the present invention in any way.
All patent and literature references cited in the present specification are hereby incorporated by reference in their entirety.
Commercially available reagents referred to in the examples were used according to manufacturer's instructions unless otherwise indicated. Antibodies used in the examples are commercially available antibodies and include, but are not limited to, anti-CD180(eBioscience MRH73-11, BD Pharmingen G28-8) and Serotec MHR73), anti-CD20 (Ancell 2H7 and BD Pharmingen 2H7), anti-CD72 (BD Pharmingen J4-117), anti-CXCR5 (R&D Systems 51505), anti-CD22 (Ancell RFB4, DAKO To15, Diatec 157, Sigma HIB-22 and Monosan BL-BC34), anti-CD22 (Leinco RFB-4 and NeoMarkers 22C04), anti-CD21 (ATCC HB-135 and ATCC HB5), anti-HLA-DOB (BD Pharmingen DOB.L1), anti-human CD79a (ZL7-4 (from Caltag or Serotec), anti-human CD79b (SN8 antibody purchased from Biomeda (Foster City, Calif.) or BDbioscience (San Diego, Calif.) or Ancell (Bayport, Minn.), SN8 antibody generated from hybridomas obtained from Roswell Park Cancer (Okazaki et al., Blood, 81(1): 84-95 (1993)) or SN8 chimeric antibody generated using antibody generated from hybridomas obtained from Roswell Park Cancer Institute (Okazaki et al., Blood, 81(1): 84-95 (1993)) and CB3-1 from BD Pharmingen), anti-CD19 (Biomeda CB-19), anti-FCER2 (Ancell BU38 and Serotec D3.6 and BD Pharmingen M-L233). The source of those cells identified in the following examples, and throughout the specification, by ATCC accession numbers is the American Type Culture Collection, Manassas, Va.
Microarray data involves the analysis of TAHO expression by the performance of DNA microarray analysis on a wide a variety of RNA samples from tissues and cultured cells. Samples include normal and cancerous human tissue and various kinds of purified immune cells both at rest and following external stimulation. These RNA samples may be analyzed according to regular microarray protocols on Agilent microarrays.
In this experiment, RNA was isolated from cells and cyanine-3 and cyanine-5 labeled cRNA probes were generated by in vitro transcription using the Agilent Low Input RNA Fluorescent Linear Amplification Kit (Agilent). Cyanine-5 was used to label the samples to be tested for expression of the PRO polypeptide, for example, the myeloma and plasma cells, and cyanine-3 was used to label the universal reference (the Stratagene cell line pool) with which the expression of the test samples were compared. 0.1 g-0.2 g of cyanine-3 and cyanine-5 labeled cRNA probe was hybridized to Agilent 60-mer oligonucleotide array chips using the In Situ Hybridization Kit Plus (Agilent). These probes were hybridized to microarrays. For multiple myeloma analysis, probes were hybridized to Agilent Whole Human Genome oligonucleotide microarrays using standard Agilent recommended conditions and buffers (Agilent).
The cRNA probes are hybridized to the microarrays at 60° C. for 17 hours on a hybridization rotator set at 4 RPM. After washing, the microarrays are scanned with the Agilent microarray scanner which is capable of exciting and detecting the fluorescence from the cyanine-3 and cyanine-5 fluorescent molecules (532 and 633 nm laser lines). The data for each gene on the 60-mer oligonucleotide array was extracted from the scanned microarray image using Agilent feature extraction software which accounts for feature recognition, background subtraction and normalization and the resulting data was loaded into the software package known as the Rosetta Resolver Gene Expression Data Analysis System (Rosetta Inpharmatics, Inc.). Rosetta Resolver includes a relational database and numerous analytical tools to store, retrieve and analyze large quantities of intensity or ratio gene expression data.
In this example, B cells and T cells (control) were obtained for microarray analysis. For isolation of naive and memory B cells and plasma cells, human peripheral blood mononuclear cells (PBMC) were separated from either leukopack provided by four healthy male donors or from whole blood of several normal donors. CD138+ plasma cells were isolated from PBMC using the MACS (Miltenyi Biotec) magnetic cell sorting system and anti-CD138 beads. Alternatively, total CD19+ B cells were selected with anti-CD19 beads and MACS sorting. After enrichment of CD19+ (purity around 90%), FACS (Moflo) sorting was performed to separate naive and memory B cells. Sorted cells were collected by subjecting the samples to centrifugation. The sorted cells were immediately lysed in LTR buffer and homogenized with QIAshredder (Qiagen) spin column and followed by RNeasy mini kit for RNA purification. RNA yield was variable from 0.4-10 μg and depended on the cell numbers.
As a control, T cells were isolated for microarray analysis. Peripheral blood CD8 cells were isolated from leukopacks by negative selection using the Stem Cell Technologies CD8 cell isolation kit (Rosette Separation) and further purified by the MACS magnetic cell sorting system using CD8 cell isolation kit and CD45RO microbeads were added to remove CD45RO cells (Miltenyi Biotec). CD8 T cells were divided into 3 samples with each sample subjected to the stimulation as follows: (1) anti-CD3 and anti-CD28, plus IL-12 and anti-IL4 antibody, (2) anti-CD3 and anti-CD29 without adding cytokines or neutralizing antibodies and (3) anti-CD3 and anti-CD28, plus IL-4, anti-IL12 antibody and anti-IFN-γ antibody. 48 hours after stimulation, RNA was collected. After 72 hours, cells were expanded by adding diluting 8-fold with fresh media. 7 days after the RNA was collected, CD8 cells were collected, washed and restimulated by anti-CD3 and anti-CD28. 16 hours later, a second collection of RNA was made. 48 hours after restimulation, a third collection of RNA was made. RNA was collected by using Qiagen Midi preps as per the instructions in the manual with the addition of an on-column DNAse I digestion after the first RW1 wash step. RNA was eluted in RNAse free water and subsequently concentrated by ethanol precipitation. Precipitated RNA was taken up in nuclease free water to a final minimum concentration of 0.5 μg/μl.
Additional control microarrays were performed on RNA isolated from CD4+ T helper T cells, natural killer (NK) cells, neutrophils (N'phil), CD14+, CD16+ and CD16− monocytes and dendritic cells (DC).
Additional microarrays were performed on RNA isolated from cancerous tissue, such as Non-Hodgkin's Lymphoma (NHL), follicular lymphoma (FL) and multiple myeloma (MM). Additional microarrays were performed on RNA isolated from normal cells, such as normal lymph node (NLN), normal B cells, such as B cells from centroblasts, centrocytes and follicular mantel, memory B cells, and normal plasma cells (PC), which are from the B cell lineage and are normal counterparts of the myeloma cell, such as tonsil plasma cells, bone marrow plasma cells (BM PC), CD19+ plasma cells (CD19+PC), CD19− plasma cells (CD19− PC). Additional microarrays were performed on normal tissue, such as cerebellum, heart, prostate, adrenal, bladder, small intestine (s. intestine), colon, fetal liver, uterus, kidney, placenta, lung, pancreas, muscle, brain, salivary, bone marrow (marrow), blood, thymus, tonsil, spleen, testes, and mammary gland.
The molecules listed below have been identified as being significantly expressed in B cells as compared to non-B cells. Specifically, the molecules are differentially expressed in naive B cells, memory B cells that are either IgGA+ or IgM+ and plasma cells from either PBMC or bone marrow, in comparison to non-B cells, for example T cells. Accordingly, these molecules represent excellent targets for therapy of tumors in mammals.
In
(1) TAHO4 (also referred herein as CD79a) was significantly expressed in non-hodgkin's lymphoma (NHL) multiple myeloma (MM) samples and normal cerebellum and normal blood. Further TAHO4 was significantly expressed in cerebellum, blood and spleen (
(2) TAHO5 (also referred herein as human CD79b) was significantly expressed in non-hodgkin's lymphoma (NHL) (
As TAHO4 and TAHO5 have been identified as being significantly expressed in B cells and in samples from B-cell associated diseases, such as Non-Hodgkin's lymphoma, follicular lymphoma and multiple myeloma as compared to non-B cells as detected by microarray analysis, the molecules are excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas, leukemias, myelomas and other cancers of hematopoietic cells.
In this assay, a 5′ nuclease assay (for example, TaqMan®) and real-time quantitative PCR (for example, Mx3000P™ Real-Time PCR System (Stratagene, La Jolla, Calif.)), were used to find genes that are significantly overexpressed in a specific tissue type, such as B cells, as compared to a different cell type, such as other primary white blood cell types, and which further may be overexpressed in cancerous cells of the specific tissue type as compared to non-cancerous cells of the specific tissue type. The 5′ nuclease assay reaction is a fluorescent PCR-based technique which makes use of the 5′ exonuclease activity of Taq DNA polymerase enzyme to monitor gene expression in real time. Two oligonucleotide primers (whose sequences are based upon the gene or EST sequence of interest) are used to generate an amplicon typical of a PCR reaction. A third oligonucleotide, or probe, is designed to detect nucleotide sequence located between the two PCR primers. The probe is non-extendible by Taq DNA polymerase enzyme, and is labeled with a reporter fluorescent dye and a quencher fluorescent dye. Any laser-induced emission from the reporter dye is quenched by the quenching dye when the two dyes are located close together as they are on the probe. During the PCR amplification reaction, the Taq DNA polymerase enzyme cleaves the probe in a template-dependent manner. The resultant probe fragments disassociate in solution, and signal from the released reporter dye is free from the quenching effect of the second fluorophore. One molecule of reporter dye is liberated for each new molecule synthesized, and detection of the unquenched reporter dye provides the basis for quantitative interpretation of the data.
The 5′ nuclease procedure is run on a real-time quantitative PCR device such as the Mx3000™ Real-Time PCR System. The system consists of a thermocycler, a quartz-tungsten lamp, a photomultiplier tube (PMT) for detection and a computer. The system amplifies samples in a 96-well format on a thermocycler. During amplification, laser-induced fluorescent signal is collected in real-time through fiber optics cables for all 96 wells, and detected at the PMT. The system includes software for running the instrument and for analyzing the data. The starting material for the screen was mRNA (50 ng/well run in duplicate) isolated from a variety of different white blood cell types (Neutrophil (Neutr), Natural Killer cells (NK), Dendritic cells (Dend.), Monocytes (Mono), T cells (CD4+ and CD8+ subsets), stem cells (CD34+) as well as 20 separate B cell donors (donor Ids 310, 330, 357, 362, 597, 635, 816, 1012, 1013, 1020, 1072, 1074, 1075, 1076, 1077, 1086, 1096, 1098, 1109, 1112) to test for donor variability. All RNA was purchased commercially (AllCells, LLC, Berkeley, Calif.) and the concentration of each was measured precisely upon receipt. The mRNA is quantitated precisely, e.g., fluorometrically.
5′ nuclease assay data are initially expressed as Ct, or the threshold cycle. This is defined as the cycle at which the reporter signal accumulates above the background level of fluorescence. The ΔCt values are used as quantitative measurement of the relative number of starting copies of a particular target sequence in a nucleic acid sample. As one Ct unit corresponds to 1 PCR cycle or approximately a 2-fold relative increase relative to normal, two units corresponds to a 4-fold relative increase, 3 units corresponds to an 8-fold relative increase and so on, one can quantitatively measure the relative fold increase in mRNA expression between two or more different tissues. The lower the Ct value in a sample, the higher the starting copy number of that particular gene. If a standard curve is included in the assay, the relative amount of each target can be extrapolated and facilitates viewing of the data as higher copy numbers also have relative quantities (as opposed to higher copy numbers have lower Ct values) and also corrects for any variation of the generalized 1Ct equals a 2 fold increase rule. Using this technique, the molecules listed below have been identified as being significantly overexpressed (i.e., at least 2 fold) in a single (or limited number) of specific tissue or cell types as compared to a different tissue or cell type (from both the same and different tissue donors) with some also being identified as being significantly overexpressed (i.e., at least 2 fold) in cancerous cells when compared to normal cells of the particular tissue or cell type, and thus, represent excellent polypeptide targets for therapy of cancer in mammals.
Summary
TAHO4 and TAHO5 expression levels in total RNA isolated from purified B cells or from B cells from 20 B cell donors (310-1112) (AllCells) and averaged (Avg. B) was significantly higher than respective TAHO4 and TAHO5 expression levels in total RNA isolated from several white blood cell types, neutrophils (Neutr), natural killer cells (NK) (a T cell subset), dendritic cells (Dend), monocytes (Mono), CD4+ T cells, CD8+ T cells, CD34+ stem cells (data not shown).
Accordingly, as TAHO4 and TAHO5 are significantly expressed on B cells as compared to non-B cells as detected by TaqMan analysis, the molecules are excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lymphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells.
In situ hybridization is a powerful and versatile technique for the detection and localization of nucleic acid sequences within cell or tissue preparations. It may be useful, for example, to identify sites of gene expression, analyze the tissue distribution of transcription, identify and localize viral infection, follow changes in specific mRNA synthesis and aid in chromosome mapping.
In situ hybridization was performed following an optimized version of the protocol by Lu and Gillett, Cell Vision 1:169-176 (1994), using PCR-generated 33P-labeled riboprobes. Briefly, formalin-fixed, paraffin-embedded human tissues were sectioned, deparaffinized, deproteinated in proteinase K (20 g/ml) for 15 minutes at 37° C., and further processed for in situ hybridization as described by Lu and Gillett, supra. A [33-P] UTP-labeled antisense riboprobe was generated from a PCR product and hybridized at 55° C. overnight. The slides were dipped in Kodak NTB2 nuclear track emulsion and exposed for 4 weeks.
33P-Riboprobe Synthesis
6.0 μl (125 mCi) of 33P-UTP (Amersham BF 1002, SA<2000 Ci/mmol) were speed vac dried.
To each tube containing dried 33P-UTP, the following ingredients were added:
2.0 μl 5× transcription buffer
1.0 μl DTT (100 mM)
2.0 μl NTP mix (2.5 mM: 10μ; each of 10 mM GTP, CTP & ATP+10 μl H2O)
1.0 μl UTP (50 μM)
1.0 μl Rnasin
1.0 μl DNA template (1 μg)
1.0 μl H2O
1.0 μl RNA polymerase (for PCR products T3=AS, T7=S, usually)
The tubes were incubated at 37° C. for one hour. 1.0 μl RQ1 DNase were added, followed by incubation at 37° C. for 15 minutes. 90 μl TE (10 mM Tris pH 7.6/1 mM EDTA pH 8.0) were added, and the mixture was pipetted onto DE81 paper. The remaining solution was loaded in a Microcon-50 ultrafiltration unit, and spun using program 10 (6 minutes). The filtration unit was inverted over a second tube and spun using program 2 (3 minutes). After the final recovery spin, 100 μl TE were added. 1 μl of the final product was pipetted on DE81 paper and counted in 6 ml of Biofluor II.
The probe was run on a TBE/urea gel. 1-3 μl of the probe or 5 μl of RNA Mrk III were added to 3 μl of loading buffer. After heating on a 95° C. heat block for three minutes, the probe was immediately placed on ice. The wells of gel were flushed, the sample loaded, and run at 180-250 volts for 45 minutes. The gel was wrapped in saran wrap and exposed to XAR film with an intensifying screen in −70° C. freezer one hour to overnight.
A. Pretreatment of Frozen Sections
The slides were removed from the freezer, placed on aluminium trays and thawed at room temperature for 5 minutes. The trays were placed in 55° C. incubator for five minutes to reduce condensation. The slides were fixed for 10 minutes in 4% paraformaldehyde on ice in the fume hood, and washed in 0.5×SSC for 5 minutes, at room temperature (25 ml 20×SSC+975 ml SQ H2O). After deproteination in 0.5 μg/nm proteinase K for 10 minutes at 37° C. (12.5 μl of 10 mg/ml stock in 250 ml prewarmed RNase-free RNAse buffer), the sections were washed in 0.5×SSC for 10 minutes at room temperature. The sections were dehydrated in 70%, 95%, 100% ethanol, 2 minutes each.
B. Pretreatment of Paraffin-Embedded Sections
The slides were deparaffinized, placed in SQ H2O, and rinsed twice in 2×SSC at room temperature, for 5 minutes each time. The sections were deproteinated in 20 μg/ml proteinase K (500 μl of 10 mg/ml in 250 ml RNase-free RNase buffer; 37° C., 15 minutes)—human embryo, or 8× proteinase K (100 μl in 250 ml Rnase buffer, 37° C., 30 minutes)—formalin tissues. Subsequent rinsing in 0.5×SSC and dehydration were performed as described above.
C. Prehybridization
The slides were laid out in a plastic box lined with Box buffer (4×SSC, 50% formamide)-saturated filter paper.
D. Hybridization
1.0×106 cpm probe and 1.0 μl tRNA (50 mg/ml stock) per slide were heated at 95° C. for 3 minutes. The slides were cooled on ice, and 48 μl hybridization buffer were added per slide. After vortexing, 50 μl 33P mix were added to 50 μl prehybridization on slide. The slides were incubated overnight at 55° C.
E. Washes
Washing was done 2×10 minutes with 2×SSC, EDTA at room temperature (400 ml 20×SSC+16 ml 0.25M EDTA, Vf=4L), followed by RNaseA treatment at 37° C. for 30 minutes (500 μl of 10 mg/ml in 250 ml Rnase buffer=20 μg/ml), The slides were washed 2×10 minutes with 2×SSC, EDTA at room temperature. The stringency wash conditions were as follows: 2 hours at 55° C., 0.1×SSC, EDTA (20 ml 20×SSC+16 ml EDTA, Vf=4L).
F. Oligonucleotides
In situ analysis was performed on a variety of DNA sequences disclosed herein. The oligonucleotides employed for these analyses were obtained so as to be complementary to the nucleic acids (or the complements thereof) as shown in the accompanying figures.
(1) DNA225785 (TAHO4)
G. Results
In situ analysis was performed on a variety of DNA sequences disclosed herein. The results from these analyses are as follows.
(1) DNA225785 (TAHO4)
Expression was observed in lymphoid cells. Specifically, in normal tissues, expression was observed in spleen and lymph nodes and coincides with B cell areas, such as germinal centers, mantle, and marginal zones. Significant expression was also observed in tissue sections of a variety of malignant lymphomas, including Hodgkin's lymphoma, follicular lymphoma, diffuse large cell lymphoma, small lymphocytic lymphoma and non-Hodgkin's lymphoma. This data is consistent with the potential role of this molecule in hematopoietic tumors, specifically B-cell tumors.
The following method describes use of a nucleotide sequence encoding TAHO as a hybridization probe for, i.e., detection of the presence of TAHO in a mammal.
DNA comprising the coding sequence of full-length or mature TAHO as disclosed herein can also be employed as a probe to screen for homologous DNAs (such as those encoding naturally-occurring variants of TAHO) in human tissue cDNA libraries or human tissue genomic libraries.
Hybridization and washing of filters containing either library DNAs is performed under the following high stringency conditions. Hybridization of radiolabeled TAHO-derived probe to the filters is performed in a solution of 50% formamide, 5×SSC, 0.1% SDS, 0.1% sodium pyrophosphate, 50 mM sodium phosphate, pH 6.8, 2×Denhardt's solution, and 10% dextran sulfate at 42° C. for 20 hours. Washing of the filters is performed in an aqueous solution of 0.1×SSC and 0.1% SDS at 42° C.
DNAs having a desired sequence identity with the DNA encoding full-length native sequence TAHO can then be identified using standard techniques known in the art.
This example illustrates preparation of an unglycosylated form of TAHO by recombinant expression in E. coli.
The DNA sequence encoding TAHO is initially amplified using selected PCR primers. The primers should contain restriction enzyme sites which correspond to the restriction enzyme sites on the selected expression vector. A variety of expression vectors may be employed. An example of a suitable vector is pBR322 (derived from E. coli; see Bolivar et al., Gene, 2:95 (1977)) which contains genes for ampicillin and tetracycline resistance. The vector is digested with restriction enzyme and dephosphorylated. The PCR amplified sequences are then ligated into the vector. The vector will preferably include sequences which encode for an antibiotic resistance gene, a trp promoter, a polyhis leader (including the first six STII codons, polyhis sequence, and enterokinase cleavage site), the TAHO coding region, lambda transcriptional terminator, and an argU gene.
The ligation mixture is then used to transform a selected E. coli strain using the methods described in Sambrook et al., supra. Transformants are identified by their ability to grow on LB plates and antibiotic resistant colonies are then selected. Plasmid DNA can be isolated and confirmed by restriction analysis and DNA sequencing.
Selected clones can be grown overnight in liquid culture medium such as LB broth supplemented with antibiotics. The overnight culture may subsequently be used to inoculate a larger scale culture. The cells are then grown to a desired optical density, during which the expression promoter is turned on.
After culturing the cells for several more hours, the cells can be harvested by centrifugation. The cell pellet obtained by the centrifugation can be solubilized using various agents known in the art, and the solubilized TAHO protein can then be purified using a metal chelating column under conditions that allow tight binding of the protein.
TAHO may be expressed in E. coli in a poly-His tagged form, using the following procedure. The DNA encoding TAHO is initially amplified using selected PCR primers. The primers will contain restriction enzyme sites which correspond to the restriction enzyme sites on the selected expression vector, and other useful sequences providing for efficient and reliable translation initiation, rapid purification on a metal chelation column, and proteolytic removal with enterokinase. The PCR-amplified, poly-His tagged sequences are then ligated into an expression vector, which is used to transform an E. coli host based on strain 52 (W3110 fuhA(tonA) Ion gale rpoHts(htpRts) clpP(lacIq). Transformants are first grown in LB containing 50 mg/ml carbenicillin at 30° C. with shaking until an O.D.600 of 3-5 is reached. Cultures are then diluted 50-100 fold into CRAP media (prepared by mixing 3.57 g (NH4)2SO4, 0.71 g sodium citrate.2H2O, 1.07 g KCl, 5.36 g Difco yeast extract, 5.36 g Sheffield hycase SF in 500 mL water, as well as 110 mM MPOS, pH 7.3, 0.55% (w/v) glucose and 7 mM MgSO4) and grown for approximately 20-30 hours at 30° C. with shaking. Samples are removed to verify expression by SDS-PAGE analysis, and the bulk culture is centrifuged to pellet the cells. Cell pellets are frozen until purification and refolding.
E. coli paste from 0.5 to 1 L fermentations (6-10 g pellets) is resuspended in 10 volumes (w/v) in 7 M guanidine, 20 mM Tris, pH 8 buffer. Solid sodium sulfite and sodium tetrathionate is added to make final concentrations of 0.1M and 0.02 M, respectively, and the solution is stirred overnight at 4° C. This step results in a denatured protein with all cysteine residues blocked by sulfitolization. The solution is centrifuged at 40,000 rpm in a Beckman Ultracentifuge for 30 min. The supernatant is diluted with 3-5 volumes of metal chelate column buffer (6 M guanidine, 20 mM Tris, pH 7.4) and filtered through 0.22 micron filters to clarify. The clarified extract is loaded onto a 5 ml Qiagen Ni-NTA metal chelate column equilibrated in the metal chelate column buffer. The column is washed with additional buffer containing 50 mM imidazole (Calbiochem, Utrol grade), pH 7.4. The protein is eluted with buffer containing 250 mM imidazole. Fractions containing the desired protein are pooled and stored at 4° C. Protein concentration is estimated by its absorbance at 280 nm using the calculated extinction coefficient based on its amino acid sequence.
The proteins are refolded by diluting the sample slowly into freshly prepared refolding buffer consisting of: 20 mM Tris, pH 8.6, 0.3 M NaCl, 2.5 M urea, 5 mM cysteine, 20 mM glycine and 1 mM EDTA. Refolding volumes are chosen so that the final protein concentration is between 50 to 100 micrograms/ml. The refolding solution is stirred gently at 4° C. for 12-36 hours. The refolding reaction is quenched by the addition of TFA to a final concentration of 0.4% (pH of approximately 3). Before further purification of the protein, the solution is filtered through a 0.22 micron filter and acetonitrile is added to 2-10% final concentration. The refolded protein is chromatographed on a Poros R1/H reversed phase column using a mobile buffer of 0.1% TFA with elution with a gradient of acetonitrile from 10 to 80%. Aliquots of fractions with A280 absorbance are analyzed on SDS polyacrylamide gels and fractions containing homogeneous refolded protein are pooled. Generally, the properly refolded species of most proteins are eluted at the lowest concentrations of acetonitrile since those species are the most compact with their hydrophobic interiors shielded from interaction with the reversed phase resin. Aggregated species are usually eluted at higher acetonitrile concentrations. In addition to resolving misfolded forms of proteins from the desired form, the reversed phase step also removes endotoxin from the samples.
Fractions containing the desired folded TAHO polypeptide are pooled and the acetonitrile removed using a gentle stream of nitrogen directed at the solution. Proteins are formulated into 20 mM Hepes, pH 6.8 with 0.14 M sodium chloride and 4% mannitol by dialysis or by gel filtration using G25 Superfine (Pharmacia) resins equilibrated in the formulation buffer and sterile filtered.
Certain of the TAHO polypeptides disclosed herein have been successfully expressed and purified using this technique(s).
This example illustrates preparation of a potentially glycosylated form of TAHO by recombinant expression in mammalian cells.
The vector, pRK5 (see EP 307,247, published Mar. 15, 1989), is employed as the expression vector. Optionally, the TAHO DNA is ligated into pRK5 with selected restriction enzymes to allow insertion of the TAHO DNA using ligation methods such as described in Sambrook et al., supra. The resulting vector is called pRK5-TAHO.
In one embodiment, the selected host cells may be 293 cells. Human 293 cells (ATCC CCL 1573) are grown to confluence in tissue culture plates in medium such as DMEM supplemented with fetal calf serum and optionally, nutrient components and/or antibiotics. About 10 μg pRK5-TAHO DNA is mixed with about 1 μg DNA encoding the VA RNA gene [Thimmappaya et al., Cell, 31:543 (1982)] and dissolved in 500 μl of 1 mM Tris-HCl, 0.1 mM EDTA, 0.227 M CaCl2. To this mixture is added, dropwise, 500 μl of 50 mM HEPES (pH 7.35), 280 mM NaCl, 1.5 mM NaPO4, and a precipitate is allowed to form for 10 minutes at 25° C. The precipitate is suspended and added to the 293 cells and allowed to settle for about four hours at 37° C. The culture medium is aspirated off and 2 ml of 20% glycerol in PBS is added for 30 seconds. The 293 cells are then washed with serum free medium, fresh medium is added and the cells are incubated for about 5 days.
Approximately 24 hours after the transfections, the culture medium is removed and replaced with culture medium (alone) or culture medium containing 200 μCi/ml 35S-cysteine and 200 μCi/ml 35S-methionine. After a 12 hour incubation, the conditioned medium is collected, concentrated on a spin filter, and loaded onto a 15% SDS gel. The processed gel may be dried and exposed to film for a selected period of time to reveal the presence of TAHO polypeptide. The cultures containing transfected cells may undergo further incubation (in serum free medium) and the medium is tested in selected bioassays.
In an alternative technique, TAHO may be introduced into 293 cells transiently using the dextran sulfate method described by Somparyrac et al., Proc. Natl. Acad. Sci., 12:7575 (1981). 293 cells are grown to maximal density in a spinner flask and 700 μg pRK5-TAHO DNA is added. The cells are first concentrated from the spinner flask by centrifugation and washed with PBS. The DNA-dextran precipitate is incubated on the cell pellet for four hours. The cells are treated with 20% glycerol for 90 seconds, washed with tissue culture medium, and re-introduced into the spinner flask containing tissue culture medium, 5 μg/ml bovine insulin and 0.1 μg/ml bovine transferrin. After about four days, the conditioned media is centrifuged and filtered to remove cells and debris. The sample containing expressed TAHO can then be concentrated and purified by any selected method, such as dialysis and/or column chromatography.
In another embodiment, TAHO can be expressed in CHO cells. The pRK5-TAHO can be transfected into CHO cells using known reagents such as CaPO4 or DEAE-dextran. As described above, the cell cultures can be incubated, and the medium replaced with culture medium (alone) or medium containing a radiolabel such as 35S-methionine. After determining the presence of TAHO polypeptide, the culture medium may be replaced with serum free medium. Preferably, the cultures are incubated for about 6 days, and then the conditioned medium is harvested. The medium containing the expressed TAHO can then be concentrated and purified by any selected method.
Epitope-tagged TAHO may also be expressed in host CHO cells. The TAHO may be subcloned out of the pRK5 vector. The subclone insert can undergo PCR to fuse in frame with a selected epitope tag such as a poly-his tag into a Baculovirus expression vector. The poly-his tagged TAHO insert can then be subcloned into a SV40 driven vector containing a selection marker such as DHFR for selection of stable clones. Finally, the CHO cells can be transfected (as described above) with the SV40 driven vector. Labeling may be performed, as described above, to verify expression. The culture medium containing the expressed poly-His tagged TAHO can then be concentrated and purified by any selected method, such as by Ni2+-chelate affinity chromatography.
TAHO may also be expressed in CHO and/or COS cells by a transient expression procedure or in CHO cells by another stable expression procedure.
Stable expression in CHO cells is performed using the following procedure. The proteins are expressed as an IgG construct (immunoadhesin), in which the coding sequences for the soluble forms (e.g. extracellular domains) of the respective proteins are fused to an IgG1 constant region sequence containing the hinge, CH2 and CH2 domains and/or is a poly-His tagged form.
Following PCR amplification, the respective DNAs are subcloned in a CHO expression vector using standard techniques as described in Ausubel et al., Current Protocols of Molecular Biology, Unit 3.16, John Wiley and Sons (1997). CHO expression vectors are constructed to have compatible restriction sites 5′ and 3′ of the DNA of interest to allow the convenient shuttling of cDNA's. The vector used expression in CHO cells is as described in Lucas et al., Nucl. Acids Res. 24:9 (1774-1779 (1996), and uses the SV40 early promoter/enhancer to drive expression of the cDNA of interest and dihydrofolate reductase (DHFR). DHFR expression permits selection for stable maintenance of the plasmid following transfection.
Twelve micrograms of the desired plasmid DNA is introduced into approximately 10 million CHO cells using commercially available transfection reagents Superfect® (Quiagen), Dosper® or Fugene® (Boehringer Mannheim). The cells are grown as described in Lucas et al., supra. Approximately 3×107 cells are frozen in an ampule for further growth and production as described below.
The ampules containing the plasmid DNA are thawed by placement into water bath and mixed by vortexing. The contents are pipetted into a centrifuge tube containing 10 mLs of media and centrifuged at 1000 rpm for 5 minutes. The supernatant is aspirated and the cells are resuspended in 10 mL of selective media (0.2 μm filtered PS20 with 5% 0.2 μm diafiltered fetal bovine serum). The cells are then aliquoted into a 100 mL spinner containing 90 mL of selective media. After 1-2 days, the cells are transferred into a 250 mL spinner filled with 150 mL selective growth medium and incubated at 37° C. After another 2-3 days, 250 mL, 500 mL and 2000 mL spinners are seeded with 3×105 cells/mL. The cell media is exchanged with fresh media by centrifugation and resuspension in production medium. Although any suitable CHO media may be employed, a production medium described in U.S. Pat. No. 5,122,469, issued Jun. 16, 1992 may actually be used. A 3 L production spinner is seeded at 1.2×106 cells/mL. On day 0, the cell number pH ie determined. On day 1, the spinner is sampled and sparging with filtered air is commenced. On day 2, the spinner is sampled, the temperature shifted to 33° C., and 30 mL of 500 g/L glucose and 0.6 mL of 10% antifoam (e.g., 35% polydimethylsiloxane emulsion, Dow Corning 365 Medical Grade Emulsion) taken. Throughout the production, the pH is adjusted as necessary to keep it at around 7.2. After 10 days, or until the viability dropped below 70%, the cell culture is harvested by centrifugation and filtering through a 0.22 μm filter. The filtrate was either stored at 4° C. or immediately loaded onto columns for purification.
For the poly-His tagged constructs, the proteins are purified using a Ni-NTA column (Qiagen). Before purification, imidazole is added to the conditioned media to a concentration of 5 mM. The conditioned media is pumped onto a 6 ml Ni-NTA column equilibrated in 20 mM Hepes, pH 7.4, buffer containing 0.3 M NaCl and 5 mM imidazole at a flow rate of 4-5 ml/min. at 4° C. After loading, the column is washed with additional equilibration buffer and the protein eluted with equilibration buffer containing 0.25 M imidazole. The highly purified protein is subsequently desalted into a storage buffer containing 10 mM Hepes, 0.14 M NaCl and 4% mannitol, pH 6.8, with a 25 ml G25 Superfine (Pharmacia) column and stored at −80° C.
Immunoadhesin (Fc-containing) constructs are purified from the conditioned media as follows. The conditioned medium is pumped onto a 5 ml Protein A column (Pharmacia) which had been equilibrated in 20 mM Na phosphate buffer, pH 6.8. After loading, the column is washed extensively with equilibration buffer before elution with 100 mM citric acid, pH 3.5. The eluted protein is immediately neutralized by collecting 1 ml fractions into tubes containing 275 μL of 1 M Tris buffer, pH 9. The highly purified protein is subsequently desalted into storage buffer as described above for the poly-His tagged proteins. The homogeneity is assessed by SDS polyacrylamide gels and by N-terminal amino acid sequencing by Edman degradation.
Certain of the TAHO polypeptides disclosed herein have been successfully expressed and purified using this technique(s).
The following method describes recombinant expression of TAHO in yeast.
First, yeast expression vectors are constructed for intracellular production or secretion of TAHO from the ADH2/GAPDH promoter. DNA encoding TAHO and the promoter is inserted into suitable restriction enzyme sites in the selected plasmid to direct intracellular expression of TAHO. For secretion, DNA encoding TAHO can be cloned into the selected plasmid, together with DNA encoding the ADH2/GAPDH promoter, a native TAHO signal peptide or other mammalian signal peptide, or, for example, a yeast alpha-factor or invertase secretory signal/leader sequence, and linker sequences (if needed) for expression of TAHO.
Yeast cells, such as yeast strain AB110, can then be transformed with the expression plasmids described above and cultured in selected fermentation media. The transformed yeast supernatants can be analyzed by precipitation with 10% trichloroacetic acid and separation by SDS-PAGE, followed by staining of the gels with Coomassie Blue stain.
Recombinant TAHO can subsequently be isolated and purified by removing the yeast cells from the fermentation medium by centrifugation and then concentrating the medium using selected cartridge filters. The concentrate containing TAHO may further be purified using selected column chromatography resins.
Certain of the TAHO polypeptides disclosed herein have been successfully expressed and purified using this technique(s).
The following method describes recombinant expression of TAHO in Baculovirus-infected insect cells.
The sequence coding for TAHO is fused upstream of an epitope tag contained within a baculovirus expression vector. Such epitope tags include poly-his tags and immunoglobulin tags (like Fc regions of IgG). A variety of plasmids may be employed, including plasmids derived from commercially available plasmids such as pVL1393 (Novagen). Briefly, the sequence encoding TAHO or the desired portion of the coding sequence of TAHO such as the sequence encoding an extracellular domain of a transmembrane protein or the sequence encoding the mature protein if the protein is extracellular is amplified by PCR with primers complementary to the 5′ and 3′ regions. The 5′ primer may incorporate flanking (selected) restriction enzyme sites. The product is then digested with those selected restriction enzymes and subcloned into the expression vector.
Recombinant baculovirus is generated by co-transfecting the above plasmid and BaculoGold™ virus DNA (Pharmingen) into Spodoptera frugiperda (“Sf9”) cells (ATCC CRL 1711) using lipofectin (commercially available from GIBCO-BRL). After 4-5 days of incubation at 28° C., the released viruses are harvested and used for further amplifications. Viral infection and protein expression are performed as described by O'Reilley et al., Baculovirus expression vectors: A Laboratory Manual, Oxford: Oxford University Press (1994).
Expressed poly-his tagged TAHO can then be purified, for example, by Ni2+-chelate affinity chromatography as follows. Extracts are prepared from recombinant virus-infected Sf9 cells as described by Rupert et al., Nature, 362:175-179 (1993). Briefly, Sf9 cells are washed, resuspended in sonication buffer (25 mL Hepes, pH 7.9; 12.5 mM MgCl2; 0.1 mM EDTA; 10% glycerol; 0.1% NP-40; 0.4 M KCl), and sonicated twice for 20 seconds on ice. The sonicates are cleared by centrifugation, and the supernatant is diluted 50-fold in loading buffer (50 mM phosphate, 300 mM NaCl, 10% glycerol, pH 7.8) and filtered through a 0.45 μm filter. A Ni2+-NTA agarose column (commercially available from Qiagen) is prepared with a bed volume of 5 mL, washed with 25 mL of water and equilibrated with 25 mL of loading buffer. The filtered cell extract is loaded onto the column at 0.5 ml per minute. The column is washed to baseline A280 with loading buffer, at which point fraction collection is started. Next, the column is washed with a secondary wash buffer (50 mM phosphate; 300 mM NaCl, 10% glycerol, pH 6.0), which elutes nonspecifically bound protein. After reaching A280 baseline again, the column is developed with a 0 to 500 mM Imidazole gradient in the secondary wash buffer. One mL fractions are collected and analyzed by SDS-PAGE and silver staining or Western blot with Ni2+-NTA-conjugated to alkaline phosphatase (Qiagen). Fractions containing the eluted His10-tagged TAHO are pooled and dialyzed against loading buffer.
Alternatively, purification of the IgG tagged (or Fc tagged) TAHO can be performed using known chromatography techniques, including for instance, Protein A or protein G column chromatography.
Certain of the TAHO polypeptides disclosed herein have been successfully expressed and purified using this technique(s).
This example illustrates preparation of monoclonal antibodies which can specifically bind TAHO.
Techniques for producing the monoclonal antibodies are known in the art and are described, for instance, in Goding, supra. Immunogens that may be employed include purified TAHO, fusion proteins containing TAHO, and cells expressing recombinant TAHO on the cell surface. Selection of the immunogen can be made by the skilled artisan without undue experimentation.
Mice, such as Balb/c, are immunized with the TAHO immunogen emulsified in complete Freund's adjuvant and injected subcutaneously or intraperitoneally in an amount from 1-100 micrograms. Alternatively, the immunogen is emulsified in MPL-TDM adjuvant (Ribi Immunochemical Research, Hamilton, Mont.) and injected into the animal's hind foot pads. The immunized mice are then boosted 10 to 12 days later with additional immunogen emulsified in the selected adjuvant. Thereafter, for several weeks, the mice may also be boosted with additional immunization injections. Serum samples may be periodically obtained from the mice by retro-orbital bleeding for testing in ELISA assays to detect anti-TAHO antibodies.
After a suitable antibody titer has been detected, the animals “positive” for antibodies can be injected with a final intravenous injection of immunogen. Three to four days later, the mice are sacrificed and the spleen cells are harvested. The spleen cells are then fused (using 35% polyethylene glycol) to a selected murine myeloma cell line such as P3X63AgU. 1, available from ATCC, No. CRL 1597. The fusions generate hybridoma cells which can then be plated in 96 well tissue culture plates containing HAT (hypoxanthine, aminopterin, and thymidine) medium to inhibit proliferation of non-fused cells, myeloma hybrids, and spleen cell hybrids.
The hybridoma cells will be screened in an ELISA for reactivity against immunogen. Determination of “positive” hybridoma cells secreting the desired monoclonal antibodies against immunogen is within the skill in the art.
The positive hybridoma cells can be injected intraperitoneally into syngeneic Balb/c mice to produce ascites containing the anti-immunogen monoclonal antibodies. Alternatively, the hybridoma cells can be grown in tissue culture flasks or roller bottles. Purification of the monoclonal antibodies produced in the ascites can be accomplished using ammonium sulfate precipitation, followed by gel exclusion chromatography. Alternatively, affinity chromatography based upon binding of antibody to protein A or protein G can be employed.
Antibodies directed against certain of the TAHO polypeptides disclosed herein can be successfully produced using this technique(s). More specifically, functional monoclonal antibodies that are capable of recognizing and binding to TAHO protein, including human and cynomologus forms of TAHO proteins, (as measured by standard ELISA, FACS sorting analysis and/or immunohistochemistry analysis) can be successfully generated against the following TAHO proteins, including human and cynomologus forms of TAHO proteins, as disclosed herein: TAHO4 (human CD79a) (DNA225785), TAHO5 (human CD79b) (DNA225786), TAHO39 (cyno CD79a) (DNA548454) and TAHO40 (cyno CD79b) (DNA548455).
In addition to the preparation of monoclonal antibodies directed against the TAHO polypeptides, including human and cynomologus forms of TAHO polypeptides, as described herein, many of the monoclonal antibodies can be successfully conjugated to a cell toxin for use in directing the cellular toxin to a cell (or tissue) that expresses a TAHO polypeptide, including human and cynomologus forms of TAHO polypeptides, of interest (both in vitro and in vivo). For example, toxin (e.g., DM1) derivitized monoclonal antibodies can be successfully generated to the following TAHO polypeptides, including human and cynomologus forms of TAHO proteins, as described herein: TAHO4 (human CD79a) (DNA225785), TAHO5 (human CD79b) (DNA225786), TAHO39 (cyno CD79a) (DNA548454) and TAHO40 (cyno CD79b) (DNA548455).
Generation of Monoclonal Antibodies to CD79a/CD79b (TAHO4, TAHO5)
Protein for immunization of mice was generated by transient transfection of vectors that express Fc-tagged or His-tagged extra-cellular domains (ECDs) of human CD79a, human CD79b or cynomologus monkey CD79b into CHO cells. The proteins were purified from the transfected cell supernatants on proteinA columns and the identity of the protein confirmed by N-terminal sequencing.
For CD79a (human) antibodies, ten Balb/c mice (Charles River Laboratories, Hollister, Calif.) were hyperimmunized with the recombinant Fc-tagged ECD of human CD79a. For CD79b (human) antibodies ten Balb/c mice (Charles River Laboratories, Hollister, Calif.) were hyperimmunized with recombinant Fc-tagged or His-tagged ECD of human CD79b. For CD79b (cynomologus monkey) antibodies, ten Balb/c mice (Charles River Laboratories, Hollister, Calif.) were hyperimmunized with the recombinant Fc-tagged ECD of cynomologus monkey CD79b protein, in Ribi adjuvant (Ribi Immunochem Research, Inc., Hamilton, Mo.).
For the human CD79a antibodies, B-cells from mice demonstrating high antibody titers against the human CD79a immunogen by direct ELISA, and specific binding to Ramos cells (CD79 positive B-cell line) versus Raji cells (CD79 minus B-cell line), were fused with mouse myeloma cells (X63.Ag8.653; American Type Culture Collection, Rockville, Md.) as previously described (Hongo, J. S. et al., Hybridoma, 14:253-260 (1995); Kohler, G. et al., Nature, 256:495-497 (1975); Freund, Y. R. et al., J. Immunol., 129:2826-2830 (1982)). For the human CD79b antibodies, B-cells from mice demonstrating high antibody titers against the human CD79b immunogen by direct ELISA, and specific binding to Ramos cells, were fused with mouse myeloma cells (X63.Ag8.653; American Type Culture Collection, Rockville, Md.) as previously described (Hongo, J. S. et al., Hybridoma, 14:253-260 (1995); Kohler, G. et al., Nature, 256:495-497 (1975); Freund, Y. R. et al., J. Immunol., 129:2826-2830 (1982)). For the cynomologus monkey CD79b antibodies, B-cells from mice demonstrating high antibody titers against the monkey CD79b immunogen by direct ELISA, and specific binding to the B-cell population of cynomologus monkey peripheral blood monouclear cells (PBMCs), were fused with mouse myeloma cells (X63.Ag8.653; American Type Culture Collection, Rockville, Md.) as previously described (Hongo, J. S. et al., Hybridoma, 14:253-260 (1995); Kohler, G. et al., Nature, 256:495-497 (1975); Freund, Y. R. et al., J. Immunol., 129:2826-2830 (1982)).
For human CD79a, human CD79b and cynomologus monkey CD79b antibodies, after 10 to 12 days, the supernatants were harvested and screened for antibody production and binding by direct ELISA and FACS as indicated above. Positive clones, showing the highest immunobinding after the second round of subcloning by limiting dilution, were expanded and cultured for further characterization, including human CD79a, human CD79b or cynomologus monkey CD79b specificity and cross-reactivity. The supernatants harvested from each hybridoma lineage were purified by affinity chromatography (Pharmacia fast protein liquid chromatography (FPLC); Pharmacia, Uppsala, Sweden) as previously described (Hongo, J. S. et al., Hybridoma, 14:253-260 (1995); Kohler, G. et al., Nature, 256:495-497 (1975); Freund, Y. R. et al., J. Immunol., 129:2826-2830 (1982)). The purified antibody preparations were then sterile filtered (0.2-μm pore size; Nalgene, Rochester N.Y.) and stored at 4° C. in phosphate buffered saline (PBS).
Monoclonal antibodies that are capable of recognizing and binding to TAHO protein (as measured by standard ELISA, FACS sorting analysis (for B-cell specificity) and/or immunohistochemistry analysis) have been successfully generated against the human-TAHO4 (CD79a) and have been designated as anti-human-CD79a-8H9 (herein referred to as “8H9” or “8H9.1.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7719 (anti-human CD79a murine monoclonal antibody 8H9.1.1), as anti-human-CD79a-5C3 (herein referred to as “5C3” or “5C3.1.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7718 (anti-human CD79a murine monoclonal antibody 5C3.1.1), as anti-human-CD79a-7H7 (herein referred to as “7H7” or “7H7.1.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7717 (anti-human CD79a murine monoclonal antibody 7H7.1.1), as anti-human-CD79a-8D11 (herein referred to as “8D11” or “8D11.1.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7722 (anti-human CD79a murine-monoclonal antibody 8D11.1.1), as anti-human-CD79a-15E4 (herein referred to as “15E4” or “15E4.1.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7721 (anti-human D791 murine monoclonal antibody 15E4.1.1) and as anti-human-CD79a-16C11 (herein referred to as “16C11” or “16C11.1.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7720 (anti-human CD79a murine monoclonal antibody 16C11.1.1).
Monoclonal antibodies that are capable of recognizing and binding to TAHO protein (as measured by standard ELISA, FACS sorting analysis (for B-cell specificity) and/or immunohistochemistry analysis) have been successfully generated against the TAHO5 (human CD79b) and have been designated as anti-human-CD79b-2F2 (herein referred to as “2F2” or “2F2.20.1”), and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7712 (anti-human CD79b 2F2.20.1).
Monoclonal antibodies that are capable of recognizing and binding to TAHO protein (as measured by standard ELISA, FACS sorting analysis (for B-cell specificity) and/or immunohistochemistry analysis) have been successfully generated against the cyno-TAHO40 (CD79b) and have been designated as anti-cyno-CD79b-3H3 (herein referred to as “3H3” or “3H3.1.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7714 (anti-cyno CD79b 3H3.1.1), anti-cyno-CD79b-8D3 (herein referred to as “8D3” or “8D3.7.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7716 (anti-cyno CD79b 8D3.7.1), anti-cyno-CD79b-9H11 (herein referred to as “9H11”, or “9H11.3.1”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7713 (anti-cyno CD79b 9H11.3.1), anti-cyno-CD79b-10D10 (herein referred to as “10D10” or “10D10.3”) and deposited with the ATCC on Jul. 11, 2006 as ATCC No. PTA-7715 (anti-cyno CD79b 10D10.3).
Construction and Sequencing of Chimeric Anti-Human CD79b (TAHO5) Antibody (chSN8)
For construction of chimeric SN8 IgG1, total RNA was extracted from SN8 hybridoma cells (obtained from Roswell Park Cancer Institute (Okazaki et al., Blood, 81(1): 84-95 (1993)) using a Qiagen RNeasy Mini Kit (Cat # 74104) and the manufacturer's suggested protocol. Using the N-terminal amino acid sequences obtained for the light and heavy chains of the SN8 monoclonal antibody, PCR primers specific for each chain were designed. Reverse primers for RT-PCR were designed to match the framework 4 of the gene family corresponding to the N-terminal sequence. Primers were also designed to add desired restriction sites for cloning. For the light chain these were Eco RV at the N-terminus, and RsrII at 3′ end of Framework 4. For the heavy chain, sites added were PvuII at the N-terminus, and ApaI slightly downstream of the VH-CH1 junction. Primer sequences are as follows:
CA1807.SNlight (SN8 light chain forward primer):
CA1808.SNlightrev (SN8 light chain reverse primer):
CA1755.HF (SN8 heavy chain forward primer):
CA1756.HR(SN8 heavy chain reverse primer):
RT-PCR reactions for light and heavy chains were carried out using a Qiagen One-step RT-PCR kit (Cat # 210210) and the suggested reaction mixes and conditions. pRK vectors for mammalian cell expression of IgGs have been previously described (Gorman et al., DNA Prot Eng Tech 2:3-10 (1990). The vector for cloning the light chain variable domain of chimeric SN8 is a derivative of pDR1 (Shalaby et al., J. Exp. Med., 175 (1): 217-225 (1992); See also
Similarly, for cloning of the heavy chain variable domain of chimeric SN8, the heavy chain RT-PCR products were digested with PvuII and ApaI and cloned into the PvuII-ApaI sites of vector pDR2 (Shalaby et al., J. Exp. Med., 175 (1): 217-225 (1992); See also
The DNA sequence was obtained for the entire coding region of the resultant murine-human chimeric light (
The plasmids were transiently transfected in 293 (an adenovirus-transformed human embryonic kidney cell line (Graham et al., J. Gen. Virol., 36: 59-74 (1977)) as described above for CHO cells. Specifically, 293 cells were split on the day prior to transfection, and plated in serum-containing medium. On the following day, double-stranded DNA prepared as a calcium phosphate precipitate was added, followed by pAdVAntage™ DNA (Promega, Madison, Wis.), and cells were incubated overnighta t 37° C. Cells were cultured in serum-free medium and harvested after 4 days. The antibody proteins were purified from the transfected cell supernatants on proteinA columns and then buffer exchanged into 10 mM sodium succinate, 140 mM NaCl, pH 6.0, and concentrated using a Centricon-10 (Amicon). The identity of the proteins confirmed by N-terminal sequencing. Protein concentrations were determined by quantitative amion acid analysis. The antibodies were tested for binding to human CD79b (TAHO5) by FACS in BJAB or RAMOS cells as described above.
Construction and Sequencing of Anti-Human CD79b (TAHO5) Antibody (ch2F2)
For construction of chimeric 2F2 IgG1, total RNA was extracted from 2F2 hybridoma cells using a Qiagen RNeasy Mini Kit (Cat # 74104) and the manufacturer's suggested protocol. Using the N-terminal amino acid sequences obtained for the light and heavy chains of the 2F2 monoclonal antibody, PCR primers specific for each chain were designed. Reverse primer's for RT-PCR were designed to match the framework 4 of the gene family corresponding to the N-terminal sequence. Primers were also designed to add desired restriction sites for cloning. For the light chain these were EcoRV at the N-terminus, and KpnI at 3′ end of Framework 4. For the heavy chain, sites added were BsiWI at the N-terrminus, and ApaI slightly downstream of the VH-CH1 junction. Primer sequences are as follows:
9C10LCF.EcoRV (2F2 light chain forward primer):
C7F7LCR.KpnI (2F2 light chain reverse primer):
13G5HCF.BsiWI (2F2 heavy chain forward primer):
C7F7HCR.ApaI (2F2 heavy chain reverse primer):
RT-PCR reactions for light and heavy chains were carried out using a Qiagen One-step RT-PCR kit (Cat # 210210) and the suggested reaction mixes and conditions. pRK vectors for mammalian cell expression of IgGs have been previously described (Gorman et al., DNA Prot Eng Tech 2:3-10 (1990). Vectors have been modified and have incorporated certain endonuclease restriction enzyme recognition sites to facilitate cloning and expression (Shields et al., J Biol Chem 2000; 276: 6591-6604). Amplified VL was cloned into a pRK mammalian cell expression vector containing the human kappa constant domain (pRK.LPG3.Human Kappa;
The DNA sequence was obtained for the entire coding region of the resultant murine-human chimeric light (
The plasmids were transiently transfected in 293 (an adenovirus-transformed human embryonic kidney cell line (Graham et al., J. Gen. Virol., 36: 59-74 (1977)) as described above or CHO cells. The antibody proteins were purified from the transfected cell supernatants on proteinA columns and the identity of the proteins. confirmed by N-terminal sequencing. The antibodies were tested for binding to human CD79b (TAHO5) by FACS in BJAB or RAMOS cells as described above.
Construction and Sequencing of Anti-Cyno CD79b (TAHO40) Antibody (ch10D10)
For construction of chimeric anti-cyno CD79b (TAHO40) (ch10D10) IgG1, Total RNA was extracted from 10D10 hybridoma cells using a Qiagen RNeasy Mini Kit (Cat # 74104) and the manufacturer's suggested protocol. Using the N-terminal amino acid sequences obtained for the light and heavy chains of the 10D10 Mab, PCR primers specific for each chain were designed. Reverse primers for RT-PCR were designed to match the framework 4 of the gene family corresponding to the N-terminal sequence. Primers were also designed to add desired restriction sites for cloning. For the light chain these were Eco RV at the N-terminus, and RsrII at 3′ end of Framework 4. For the heavy chain, sites added were PvuII at the N-terminus, and ApaI slightly downstream of the VH-CH1 junction. Primer sequences are shown as follows:
Light chain forward: CA1836
Light chain reverse: CA1808
Heavy chain forward: CA1834:
Heavy chain reverse: CA1835
RT-PCR reactions for light chain was carried out using a Qiagen One-step RT-PCR kit (Cat # 210210) and the suggested reaction mixes and conditions. For the heavy chain, Superscript III First Strand Synthesis System for RT-PCR, Invitrogen cat #18080-051 was used followed by amplification with Platinum Taq DNA polymerase (Invitrogen). Reactions and conditions were as recommended by manufacturer. pRK vectors for mammalian cell expression of IgGs have been previously described (Gorman et al., DNA Prot Eng Tech 2:3-10 (1990). The vector for cloning the light chain variable domain of chimeric 10D10 is a derivative of pDR1 (Shalaby et al., J. Exp. Med., 175 (1): 217-225 (1992); See also
Similarly, for cloning of the heavy chain variable domain of chimeric 10D10, the heavy chain RT-PCR products were digested with PvuII and ApaI and cloned into the PvuII-ApaI sites of vector pDR2 (Shalaby et al., J. Exp. Med., 175 (1): 217-225 (1992); See also
The DNA sequence was obtained for the entire coding region of the resultant murine-human chimeric light (
The plasmids were transiently transfected in 293 (an adenovirus-transformed human embryonic kidney cell line (Graham et al., J. Gen. Virol., 36: 59-74 (1977)) as described above for CHO cells. Specifically, 293 cells were split on the day prior to transfection, and plated in serum-containing medium. On the following day, double-stranded DNA prepared as a calcium phosphate precipitate was added, followed by pAdVAntage™ DNA (Promega, Madison, Wis.), and cells were incubated overnight at 37° C. Cells were cultured in serum-free medium and harvested after 4 days. The antibody proteins were purified from the transfected cell supernatants on proteinA columns and then buffer exchanged into 10 mM sodium succinate, 140 mM NaCl, pH 6.0, and concentrated using a Centricon-10 (Amicon). The identity of the proteins confirmed by N-terminal sequencing. Protein concentrations wre determined by quantitative amino acid analysis. The antibodies were tested for binding to cyno CD79b (TAHO40) by FACS in BJAB-cyno CD79b cells (a BJAB cell line expressing cyno CD79b (TAHO40), described below.
Characterization of CD79b Antibodies
The epitope to which anti-human CD79b (TAHO5) antibodies and anti-cyno-CD79b (TAHO40) antibodies bind were determined. For determination of the epitope, CD79b gene from both cynomologus and rhesus monkeys were cloned, using the primers flanking the non-coding region of the CD79b gene, which is very conservative between the human and mouse CD79b, suggesting that it should also be conservative in primates.
Alternatively spliced forms of human CD79b (TAHO5), a full-length and a truncated form lacking the entire extracellular Ig-like domain (the extracellular Ig-like domain that is not present in the spliced truncated form of CD79b is boxed in
The extracellular peptide region distal to the transmembrane domain and present in both the full-length and truncated human CD79b forms was compared to the same region in cynomologus and rhesus CD79b. The only difference in this region aside from the signal peptide sequences, between human CD79b (TAHO5) and cynomologus (TAHO40) or rhesus CD79b, is a 11 amino acid region with only three amino acid differences, ARSEDRYRNPK (human) (SEQ ID NO: 16) and AKSEDLYPNPK (cynomologus and rhesus) (SEQ ID NO: 17). The 11 amino acid region in human, cynomolgus and murine CD79b is shown in
To determine whether peptides with the 11 amino acid region were able to compete for antibody binding, BJAB cells were used in a competition assay. 21mer peptides comprising the 11 amino acid region were generated for human CD79b (TAHO5) and cyno CD79b (TAHO40), and the sequences of SEQ ID NO: 26 (ARSEDRYRNPKGSACSRIWQS) and SEQ ID NO: 27 (AKSEDLYPNPKGSACSRIWQS), respectively. Anti-human CD79b (TAHO5) or anti-cynomologus CD79b (TAHO40) antibodies were first incubated with the ECD portion of the human CD79b (TAHO5) or cynomologus CD79b (TAHO40) protein (in a ratio of antibody: protein of 1:3) or the 21mer human or cyno peptides (in a ratio of antibody: protein of 1:10) covering the region which is different between human CD79b (TAHO5) and cynomologus CD79b (TAHO40) for 30 minutes at room temperature. After the pre-incubation step, antibodies were added to the BJAB cells and proceeded with the regular staining and FACS steps, with a rat anti-mouse IgG1-PE antibody (BD Bioscience, clone G18-145) used as a secondary antibody.
The human CD79b (TAHO5) 21 mer peptide inhibited the binding of anti-human CD79b (TAHO5) antibodies, including CB3-1 (BDbioscience, San Diego, Calif.) SN8 (Biomeda, Foster City, Calif. or BDbioscience, San Diego, Calif.), AT105 (Abcam, Cambridge, Mass.), and 2F2 (described above)) and did not inhibit the binding of control anti-cyno CD79b (TAHO40) antibodies (3H3, 8D3, 9H11 or 10D10) nor anti-human CD79a (TAHO4) antibodies (ZL7-4; Caltag or Serotec (Raleigh, N.C.)) (Zhang, L. et al., Ther. Immunol., 2:191-202 (1997)). The cyno CD79b (TAHO40) 20 mer peptides inhibited the binding of anti-cyno CD79b (TAHO40) antibodies, including 3H3, 8D3, 9H11 and 10D10 (described above) and did not inhibit the binding of control anti-human CD79b (TAHO5) antibodies (CB3-1, SN8, AT105, 2F2) nor anti-human CD79a (TAHO4) antibodies (ZL7-4). As a control, ECD of human CD79b (TAHO5) inhibited the binding of anti-human CD79b (TAHO5) antibodies, including CB3-1 (BDbioscience, San Diego, Calif.) SN8 (Biomeda, Foster City, Calif. or BDbioscience, San Diego, Calif.), AT105 (Abcam, Cambridge, Mass.), and 2F2 (described above)) and did not inhibit the binding of control anti-human CD79a (TAHO4) antibodies (ZL7-4; Caltag or Serotec (Raleigh, N.C.)) (Zhang, L.et al., Ther. Immunol., 2:191-202 (1997)).
To further determine the epitope binding of anti-human CD79b (TAHO5) antibodies, three 11mer peptides of the 11-mer human CD79b peptide (N term-ARSEDRYRNPK-C term) (SEQ ID NO: 16) were generated with single amino acid mutations of the three Arg residues in the human CD79b peptide mutated to the amino acids in the same respective positions in the cyno CD79 peptide, and herein designated as peptide mutatations 1-3. Peptide mutation 1 (N term-AKSEDRYRNPK-C term; SEQ ID NO: 18) included a mutation of the Arg residue at position 2 of SEQ ID NO: 16. Peptide mutation 2 (N term-ARSEDLYRNPK-C term; SEQ ID NO: 19) included a mutation of the Arg residue at position 6 of SEQ ID NO: 16. Peptide mutation 3 (N term-ARSEDRYPNPK-C term; SEQ ID NO: 20) included a mutation of the Arg residue at position 8 of SEQ ID NO: 16. The competition assays were performed as described above. The competition assays further demonstrated that all three Arg residues (at position 2, 6, and 8 in SEQ ID NO: 16) in the 11mer human CD79b peptide were critical for the binding of anti-human CD79b (TAHO5) (SN8) antibody, but only the middle Arg residue (at position 6 in SEQ ID NO: 16) in the 11mer human CD79b peptide was critical for binding of anti-human CD79b (TAHO5) (2F2) antibody binding.
To further determine the epitope binding of anti-cyno CD79b (TAHO40) antibodies, an 11mer peptide of the 11-mer cyno CD79b peptide (N term-AKSEDLYPNPK-C term; SEQ ID NO: 17) was generated with a single amino acid mutation of the Leu residue in the cyno CD79b peptide and designated as “peptide mutation 4”. Peptide mutation 4 (N term-AKSEDRYPNPK-C term; SEQ ID NO: 25) included a Arg residue in place of the Leu residue at position 6 of SEQ ID NO: 17. The competition assays were performed as described above. The competition assays further demonstrated that the Leu residue (at position 6 in SEQ ID NO: 17) in the 11mer cyno CD79b peptide was critical for the binding of anti-cyno CD79b (TAHO40) antibody (10D10).
Kd Scatchard analysis on BJAB-cyno CD79b cells (a BJAB cell line expressing cyno CD79b (TAHO40) described in Example 11) for anti-human CD79b (TAHO5) and anti-cyno CD79b (TAHO40) antibodies showed similar Kd values. Anti-human CD79b (SN8) bound the cells with a 0.5 nM kD while anti-cyno CD79b (10D10) bound the cells with a 1.0 nM Kd. Anti-cynoCD79b (3H3) bound the cells with a 2.0 nM Kd. Anti-cynoCD79b (8D3) bound the cells with a 2.5 nM Kd. Anti-cynoCD79b (9H11) bound the cells with a 2.6 nM Kd.
Generation of Antibody-Drug Conjugates (ADCs) with Antibodies to Human CD79a (TAH04), Human CD79b (TAHO5) and cyno CD79b (TAHO40)
The drugs used for generation of antibody drug conjugates (ADCs) for anti-human CD79a (TAH04), anti-human CD79b (TAHO5) and anti-cyno CD79b (TAHO40) included maytansinoid DM1 and dolastatin10 derivatives monmethylauristatin E (MMAE) and monomethylauristatin F (MMAF). (US 2005/0276812; US 2005/0238649; Doronina et al., Bioconjug. Chem., 17:114-123 (2006); Doronina et al., Nat. Biotechnol., 21: 778-784 (2003); Erickson et al., Cancer Res., 66: 4426-4433 (2006), all of which are herein incorporated by reference in their entirety). MMAF, unlike MMAE and DM1, is relative membrane impermeable at neutral pH, so has relatively low activity as a free drug, although it is very potent once inside the cell. (Doronina et al., Bioconjug. Chem., 17:114-123 (2006)), DM1, MMAE and MMAF are mitotic inhibitors that are at least 100 fold more cytotoxic than the vinca alkaloid mitotic inhibitors used in chemotherapeutic treatments of NHLs (Doronina et al., Bioconjug. Chem., 17:114-123 (2006); Doronina et al., Nat. Biotechnol., 21: 778-784 (2003); Erickson et al., Cancer Res., 66: 4426-4433 (2006)). The linkers used for generation of the ADCs were SPP or SMCC for DM1 and MC or MC-vc-PAB for MMAE and MMAF. For DM1, the antibodies were linked to the thio group of DM1 and through the ε-amino group of lysine using the linker reagent SMCC. Alternatively, for DM1, the antibodies were linked to DM1 through the e-amino group of lysine using the SPP linker. SPP(N-succinimidyl 4-(2′-pyridldithio) pentanoate) reacts with the epsilon amino group of lysines to leave a reactive 2-pyridyl disulfide linker on the protein. With SPP linkers, upon reaction with a free sulfhydral (e.g. DM1), the pyridyl group is displaced, leaving the DM1 attached via a reducible disulfide bond. DM1 attached via a SPP linker is released under reducing conditions (i.e., for example, within cells) while DM1 attached via the SMCC linker is resistant to cleavage in reducing conditions. Further, SMCC-DM1 ADCs induce cell toxicity if the ADC is internalized and targeted to the lysosome causing the release of lysine-Nε-DM1, which is an effective anti-mitotic agent inside the cell, and when released from the cell, lysine-Nε-DM1 is non-toxic (Erickson et al., Cancer Res., 66: 4426-4433 (2006)) For MMAE and MMAF, the antibodies were linked to MMAE or MMAF through the cysteine by maleeimidocaproyl-valine-citruline (vc)-p-aminobenzyloxycarbonyl (MC-vc-PAB). For MMAF, the antibodies were alternatively linked to MMAF through the cysteine by maleeimidocaproyl (MC) linker. The MC-vc-PAB linker may be cleaved by intercellular proteases such as cathepsin B and when cleaved, releases free drug (Doronina et al., Nat. Biotechnol., 21: 778-784 (2003)) while the MC linker may be resistant to cleavage by intracellular proteases.
Antibody drug conjugates (ADCs) for anti-human CD79a (TAHO4), anti-human CD79b (TAHO5), and anti-cyno CD79b (TAHO40), using SMCC and DM1, were generated similar to the procedure described in US 2005/0276812. Anti-human CD79a (TAHO4), anti-human CD79b (TAHO5), and anti-cyno CD79b (TAHO40) purified antibodies were buffer-exchanged into a solution containing 50 mM potassium phosphate and 2 mM EDTA, pH 7.0. SMCC (Pierce Biotechnology, Rockford, Ill.) was dissolved in dimethylacetamide (DMA) and added to the antibody solution to make a final SMCC/Ab molar ratio of 10:1. The reaction was allowed to proceed for three hours at room temperature with mixing. The SMCC-modified antibody was subsequently purified on a GE Healthcare HiTrap desalting column (G-25) equilibrated in 35 mM sodium citrate with 150 mM NaCl and 2 mM EDTA, pH 6.0. DM1, dissolved in DMA, was added to the SMCC antibody preparation to give a molar ratio of DM1 to antibody of 10:1. The reaction was allowed to proceed for 4-20 hrs at room temperature with mixing. The DM1-modified antibody solution was diafiltered with 20 volumes of PBS to remove unreacted DM1, sterile filtered, and stored at 4 degrees C. Typically, a 40-60% yield of antibody was achieved through this process. The preparation was usually >95% monomeric as assessed by gel filtration and laser light scattering. Since DM1 has an absorption maximum at 252 nm, the amount of drug bound to the antibody could be determined by differential absorption measurements at 252 and 280 nm. Typically, the drug to antibody ratio was 3 to 4.
Antibody drug conjugates (ADCs) for anti-human CD79a (TAHO4), anti-human CD79b (TAHO5), and anti-cyno CD79b (TAHO40), using SPP-DM1 linkers were generated similar to the procedure described in US 2005/0276812. Anti-human CD79a (TAHO4), anti-human CD79b (TAHO5), and anti-cyno CD79b (TAHO40) purified antibodies were buffer-exchanged into a solution containing 50 mM potassium phosphate and 2 mM EDTA, pH 7.0 SPP (Immunogen) was dissolved in DMA and added to the antibody solution to make a final SPP/Ab molar ratio of approximately 10:1, the exact ratio depending upon the desired drug loading of the antibody. A 10:1 ratio will usually result in a drug to antibody ratio of approximately 3-4. The SPP was allowed to react for 3-4 hours at room temperature with mixing. The SPP-modified antibody was subsequently purified on a GE Healthcare HiTrap desalting column (G-25) equilibrated in 35 mM sodium citrate with 150 mM NaCl and 2 mM EDTA, pH 6.0 or phosphate buffered saline, pH 7.4. DM1 was dissolved in DMA and added to the SPP antibody preparation to give a molar ratio of DM1 to antibody of 10:1, which results in a 3-4 fold molar excess over the available SPP linkers on the antibody. The reaction with DM1 was allowed to proceed for 4-20 hrs at room temperature with mixing. The DM1-modified antibody solution was diafiltered with 20 volumes of PBS to remove unreacted DM1, sterile filtered, and stored at 4 degrees C. Typically, yields of antibody of 40-60% or greater were achieved with this process. The antibody-drug conjugate was usually >95% monomeric as assessed by gel filtration and laser light scattering. The amount of bound drug is determined by differential absorption measurements at 252 and 280 nm as described for the preparation of SMCC-DM1 conjugates (described above).
Antibody drug conjugates (ADC) for anti-human CD79a (TAHO4), anti-human CD79b (TAHO5) and anti-cyno CD79b (TAHO40), using MC-MMAF, MC-MMAE, MC-val-cit (vc)-PAB-MMAE or MC-val-cit (vc)-PAB-MMAF drug linkers were generated similar to the procedure described in US 2005/0238649. Purified anti-human CD79a (TAH04), anti-human CD79b (TAHO5), or anti-cyno CD79b (TAHO40) antibody was dissolved in 500 mM sodium borate and 500 mM sodium chloride at pH 8.0 and further treated with an excess of 100 mM dithiothreitol (DTT). After incubation at 37 degrees C. for about 30 minutes, the buffer is exchanged by elution over Sephadex G25 resin and eluted with PBS with 1 mM DTPA. The thiol/Ab value was checked by determining the reduced antibody concentration from the absorbance at 280 nm of the solution and the thiol concentration by reaction with DTNB (Aldrich, Milwaukee, Wis.) and determination of the absorbance at 412 nm. The reduced antibody dissolved in PBS was chilled on ice. The drug linker, for example, MC-val-cit (vc)-PAB-MMAE, in DMSO, was dissolved in acetonitrile and water, and added to the chilled reduced antibody in PBS. After an hour incubation, an excess of maleimide was added to quench the reaction and cap any unreacted antibody thiol groups. The reaction mixture was concentrated by centrifugal ultrafiltration and the antibody drug conjugate, was purified and desalted by elution through G25 resin in PBS, filtered through 0.2 μm filters under sterile conditions, and frozen for storage.
Native or recombinant TAHO polypeptides may be purified by a variety of standard techniques in the art of protein purification. For example, pro-TAHO polypeptide, mature TAHO polypeptide, or pre-TAHO polypeptide is purified by immunoaffinity chromatography using antibodies specific for the TAHO polypeptide of interest. In general, an immunoaffinity column is constructed by covalently coupling the anti-TAHO polypeptide antibody to an activated chromatographic resin.
Polyclonal immunoglobulins are prepared from immune sera either by precipitation with ammonium sulfate or by purification on immobilized Protein A (Pharmacia LKB Biotechnology, Piscataway, N.J.). Likewise, monoclonal antibodies are prepared from mouse ascites fluid by ammonium sulfate precipitation or chromatography on immobilized Protein A. Partially purified immunoglobulin is covalently attached to a chromatographic resin such as CnBr-activated SEPHAROSE™ (Pharmacia LKB Biotechnology). The antibody is coupled to the resin, the resin is blocked, and the derivative resin is washed according to the manufacturer's instructions.
Such an immunoaffinity column is utilized in the purification of TAHO polypeptide by preparing a fraction from cells containing TAHO polypeptide in a soluble form. This preparation is derived by solubilization of the whole cell or of a subcellular fraction obtained via differential centrifugation by the addition of detergent or by other methods well known in the art. Alternatively, soluble TAHO polypeptide containing a signal sequence may be secreted in useful quantity into the medium in which the cells are grown.
A soluble TAHO polypeptide-containing preparation is passed over the immunoaffinity column, and the column is washed under conditions that allow the preferential absorbance of TAHO polypeptide (e.g., high ionic strength buffers in the presence of detergent). Then, the column is eluted under conditions that disrupt antibody/TAHO polypeptide binding (e.g., a low pH buffer such as approximately pH 2-3, or a high concentration of a chaotrope such as urea or thiocyanate ion), and TAHO polypeptide is collected.
Mammalian cells expressing the TAHO polypeptide of interest may be obtained using standard expression vector and cloning techniques. Alternatively, many tumor cell lines expressing TAHO polypeptides of interest are publicly available, for example, through the ATCC and can be routinely identified using standard ELISA or FACS analysis. Anti-TAHO polypeptide monoclonal antibodies (commercially available and toxin conjugated derivatives thereof) may then be employed in assays to determine the ability of the antibody to kill TAHO polypeptide expressing cells in vitro.
For example, cells expressing the TAHO polypeptide of interest were obtained as described above and plated into 96 well dishes. In one analysis, the antibody/toxin conjugate (or naked antibody) was included throughout the cell incubation for a period of 4 days. In a second independent analysis, the cells were incubated for 1 hour with the antibody/toxin conjugate (or naked antibody) and then washed and incubated in the absence of antibody/toxin conjugate for a period of 4 days. Cell viability was then measured using the CellTiter-Glo Luminescent Cell Viability Assay from Promega (Cat# G7571). Untreated cells served as a negative control.
For analysis of anti-human CD79a (TAHO4) and anti-human CD79b (TAHO5) antibodies, B cell lines (ARH-77, BJAB, Daudi, DOHH-2, Su-DHL-4, Raji and Ramos) were prepared at 5000 cells/well in separate sterile round bottom 96 well tissue culture treated plates (Cellstar 650 185). Cells were cultured in assay media (RPMI 1460, 1% L-Glutamine, 10% fetal bovine serum (FBS; from Hyclone) and 10 mM HEPES). Cells were immediately placed in a 37° C. incubator overnight.
For analysis of anti-cyno CD79b (TAHO40) antibodies, a transgenic cyno CD79b (TAHO40) BJAB cell line (herein referred to as “BJAB-cyno CD79b” or “BJAB.cynoCD79b” or “BJAB cynoCD79b”) was generated. A BJAB cell line (Burkitt's lymphoma cell line that contain the t(2;8)(p112;q24) (IGK-MYC) translocation, a mutated p53 gene and are Epstein-Barr virus (EBV) negative) (Drexler, H.G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press, 2001) was transfected with an expression vector containing cyno CD79b (TAHO40) (herein referred to as “pRK.CMF.PD.cynoCD79b”) by normal AMAXA nucleofection protocol (Solution T, Program T-16) (AMAXA Inc., Gaithersburg, Md.). For pRK.CMF.PD.cynoCD79b, cynomolgus CD79b (TAHO40) was cloned. For cloning of cynomolgus CD79a (TAH039) and CD79b (TAHO40), the mouse and human DNA sequences for cyno CD79a (TAHO39) and cyno CD79b (TAHO40) were aligned. Primers to conserved sequences flanking the open reading frame were generated as follows:
cynoCD79a (TAHO39) Forward Primer: 5′-TCAAACTAACCAACCCACTGGGAG-3′ (SEQ ID NO: 21)
cynoCD79a (TAHO39) Reverse Primer: 5′-CAGCGATTAAGGGCTCATTACCC-3′ (SEQ ID NO: 22)
cynoCD79b (TAH040) Forward Primer: 5′-TCGGGGACAGAGCAGTGACC-3′ (SEQ ID NO: 23)
cynoCD79b (TAH040) Reverse Primer: 5′-CAAGAGCTGGGGACCAGGGG-3′ (SEQ ID NO: 24)
Using the cyno CD79a (TAHO39) and CD79b (TAHO40) primers, the genes for cynomolgus CD79a (TAHO39) and CD79b (TAHO40) were amplified out of a cynomolgus spleen DNA library. The PCR products were cloned into the TA vector (Invitrogen) and sequenced. The cynomolgus CD79a and cynomolgus CD79b ORFs were subcloned into an expression vector driven by the CMV promoter and containing a puromycin resistance gene) (herein referred to as “pRK.CMV.PD”)
After transfection of pRK.CMF.PD.cynoCD79b into the BJAB cells and puromycin (Calbiochem, San Diego, Calif.) selection, surviving cells were FACS autocloned for top 5% expressers with anti-cyno CD79b antibodies (3H3). The best expressing BJAB cell line expressing cyno CD79b (TAHO40) was chosen by FACS analysis. The transfected BJAB cells expressing cyno CD79b (TAHO40) also express human CD79a (TAHO4) and human CD79b (TAHO5). As a control, non-transfected BJAB B-cells which express human CD79a (TAHO4) and human CD79b (TAHO5) were used.
Antibody drug conjugates (using commercially available anti-human CD79a (TAHO4), such as ZL7-4, and anti-human CD79b (TAHO5), such as SN8, or anti-human CD79a (TAHO4), anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40) antibodies described in Example 9) were diluted at 2×10 μg/ml in assay medium. Conjugates were linked with crosslinkers SMCC or disulfide linker SPP to maytansinoid DM1 toxin (See Example 9 and U.S. application Ser. Nos. 11/141,344, filed May 31, 2005 and U.S. application Ser. No. 10/983,340, filed Nov. 5, 2004). Further, conjugates may be linked with MC-valine-citrulline (vc)-PAB or MC to dolastatin 10 derivatives, monomethylauristatin E (MMAE) toxin or monomethylauristatin F (MMAF) toxin (See Example 9 U.S. application Ser. Nos. 11/141,344, filed May 31, 2005 and U.S. application Ser. No. 10/983,340, filed Nov. 5, 2004). Negative controls included HERCEPTIN® (trastuzumab) based conjugates (SMCC-DM1 or SPP-DM1 or MC-vc-MMAE or MC-vc-MMAF). Positive controls included free L-DM1 equivalent to the conjugate loading dose. Samples were vortexed to ensure homogenous mixture prior to dilution. The antibody drug conjugates were further diluted serially 1:3. The cell lines were loaded 501 of each sample per row using a Rapidplate® 96/384 Zymark automation system. When the entire plate was loaded, the plates were reincubated for 3 days to permit the toxins to take effect. The reactions were stopped by applying 100 μl/well of Cell Glo (Promega, Cat. #G7571/2/3) to all the wells for 10 minutes. The 100 μl of the stopped well were transferred into 96 well white tissue culture treated plates, clear bottom (Costar 3610) and the luminescence was read and reported as relative light units (RLU). TAHO antibodies for this experiment included commercially available antibodies, including anti-human CD79a (TAHO4) (ZL7-4) and anti-human CD79b (TAHO5) (SN8).
Summary
a. Anti-human CD79a (TAHO4)
Anti-human-CD79a (TAHO4) (ZL7-4) antibody conjugated to DM1 toxin (anti-human-CD79a (ZL7-4)-SMCC-DM1) showed significant tumor cell killing when compared to anti-human-CD79a (TAHO4) (ZL7-4) antibody alone or negative control anti-HER2 conjugated to DM1 toxin (anti-HER2-SMCC-DM1) in RAMOS cells (data not shown).
b-1. Anti-human CD79b (TAHO5)
Anti-human-CD79b (TAHO5) (SN8) antibody conjugated to DM1 toxin (anti-human-CD79b (SN8)-SMCC-DM1) showed significant tumor cell killing when compared to anti-human-CD79b (TAHO5) (SN8) antibody alone or negative control anti-HER2 conjugated to DM1 toxin (anti-HER2-SMCC-DM1) in RAMOS cells.
b-2 Anti-cyno CD79b (TAHO40)
(1) DM1 ADCs
(a) BJAB-cyno CD79b Cells
Anti-cyno CD79b (TAHO40) antibody (10D10) conjugated with DM1 (anti-cyno CD79b (10D10)-SMCC-DM1) showed significant tumor killing in BJAB-cyno CD79b cells. The killing was compared to negative controls, anti-cyno CD79b (TAHO40) antibody (10D10) alone, HERCEPTIN® (trastuzumab) antibody conjugated with DM1 (HERCEPTIN® (trastuzumab)-SMCC-DM1) (negative control) and no antibody which did not show significant tumor cell killing in BJAB-cyno CD79b cells. As positive controls, DM-1 dimer alone, and anti-human CD79b (TAHO5) antibody (SN8) conjugated with DM1 (anti-human CD79b (SN8)-SMCC-DM1) was also compared and showed significant tumor cell killing in BJAB-cyno CD79b cells.
Anti-cyno CD79b (10D10)-SMCC-DM1 with an IC50 of 0.33 nM showed greater killing of BJAB-cyno CD79b cells than anti-human CD79b (SN8)-SMCC-DM1 with an IC50 of 1.2 nM or HERCEPTIN® (trastuzumab)-SMCC-DM1 with an IC50 of 26 nM which did not show significant tumor killing in BJAB-cyno CD79b cells.
(b) BJAB Cells
As a control, anti-cyno CD79b (TAHO40) antibody (10D10) conjugated with DM1 (anti-cyno CD79b (10D10)-SMCC-DM1) was analyzed in BJAB cells (not transfected) and did not show significant tumor killing in BJAB cells. Negative controls, anti-cyno CD79b (TAHO40) antibody (10D10) alone, HERCEPTIN® (trastuzumab) antibody conjugated with DM1 (HERCEPTIN® (trastuzumab)-SMCC-DM1) and no antibody, also did not show significant tumor cell killing in BJAB cells. As positive controls, DM-1 dimer alone, and anti-human CD79b (TAHO5) antibody (SN8) conjugated with DM1 (anti-human CD79b (SN8)-SMCC-DM1) was also compared and showed significant tumor cell killing in BJAB cells.
Anti-cyno CD79b (10D10)-SMCC-DM1 with an IC50 of 10 nM and HERCEPTIN® (trastuzumab)-SMCC-DM1 with an IC50 of 30 nM did not show significant killing in BJAB cells while anti-human CD79b (SN8)-SMCC-DM1 with an IC50 of 0.4 nM showed significant killing of BJAB cells.
(2) MMAF ADCs
(a) BJAB-cyno CD79b Cells
Anti-cyno CD79b (TAHO40) antibody (10D10) conjugated with MMAF (anti-cyno CD79b (10D10)-MC-MMAF) showed significant tumor cell killing in BJAB-cyno CD79b cells compared to negative controls, anti-cyno CD79b (TAHO40) antibody (10D10), anti-human CD79b (TAHO5) antibody (SN8), HERCEPTIN® (trastuzumab) antibody, and HERCEPTIN® (trastuzumab) conjugated with MMAF (HERCEPTIN® (trastuzumab)-MC-MMAF) which did not show significant tumor cell killing in BJAB-cyno CD79b cells. A positive control, anti-human CD79b (TAHO5) (SN8) antibody conjugated with MMAF (anti-human CD79b (SN8)-MC-MMAF) was also compared and showed significant tumor cell killing in BJAB-cyno CD79b cells.
Anti-cyno CD79b (10D10)-MC-MMAF with an IC50 of 0.07 nM showed greater killing of BJAB-cyno CD79b cells than anti-human CD79b (SN8)-MC-MMAF with an IC50 of 0.6 nM.
(b) BJAB Cells
As a control, anti-cyno CD79b (TAHO40) antibody (10D10) conjugated with MMAF (anti-cyno CD79b (10D10)-MC-MMAF) was analyzed in BJAB cells and did not show significant tumor cell killing in BJAB cells. Negative controls, anti-cyno CD79b (TAHO40) antibody (10D10), anti-human CD79b (TAHO5) antibody (SN8), HERCEPTIN® (trastuzumab) antibody, and HERCEPTIN® (trastuzumab) conjugated with MMAF (HERCEPTIN® (trastuzumab)-MC-MMAF) also did not show significant tumor cell killing in BJAB cells. A positive control, anti-human CD79b (TAHO5) (SN8) antibody conjugated with MMAF (anti-human CD79b (SN8)-MC-MMAF) was also compared and showed significant tumor cell killing in BJAB cells.
Anti-cyno CD79b (10D10)-MC-MMAF with an IC50 of 694 nM did not show significant tumor cell killing in BJAB cells while anti-human CD79b (SN8)-MC-MMAF with an IC50 of 0.2 nM showed significant tumor cell killing in BJAB cells.
In light of the ability of anti-TAHO antibodies to show significant tumor cell killing, TAHO molecules may be excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells. Anti-TAHO polypeptide monoclonal antibodies are useful for reducing in vitro tumor growth of tumors, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells. Specifically, given the similarities in epitope, affinity and in vitro efficacy of the anti-cyno CD79b (TAHO40) antibodies with the anti-human CD79b (TAHO5) antibodies, anti-cyno CD79b (TAHO40) antibodies may be excellent surrogates in toxicology studies and efficacy studies in cynomologus monkey for anti-human CD79b (TAHO5) antibody.
1. Xenografts
To test the efficacy of conjugated or unconjugated anti-TAHO polypeptide monoclonal antibodies, the effect of anti-TAHO antibody on tumors in iruce were analyzed. Specifically, the ability of the antibodies to regress tumors in multiple xenograft models, including RAJI cells, RAMOS cells, BJAB cells (Burkitt's lymphoma cell line that contain the t(2;8)(p112;q24) (IGK-MYC) translocation, a mutated p53 gene and are Epstein-Barr virus (EBV) negative) (Drexler, H.G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press; 2001)), Granta 519 cells (mantle cell lymphoma cell line that contains the t(11;14)(q13;q32) (BCL1-IGH) translocation that results in the over-expression of cyclin D1 (BCL1), contains P16INK4B and P16INK4A deletions and are EBV positive) (Drexler, H. G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press, 2001)), U698M cells (lymphoblastic lymphosarcoma B cell line; (Drexler, H. G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press, 2001) and DoHH2 cells (follicular lymphoma cell line that contains the translocation characteristic of follicular lymphoma t(14;18)(q32;q21) that results in the over-expression of Bcl-2 driven by the Ig heavy chain, contains the P16INK4A deletion, contains the t(8;14)(q24;q32) (IGH-MYC) translocation and are EBV negative) (Drexler, H. G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press, 2001)), was examined.
For analysis of efficacy of anti-human CD79a or anti-human CD79b antibodies, female CB17 ICR SCID mice (6-8 weeks of age from Charles Rivers Laboratories; Hollister, Calif.) were inoculated subcutaneously with 5×106 RAJI cells, 5×106 RAMOS cells, 2×107 BJAB-luciferase cells, 2×107 Granta 519 cells, 5×106 U698M cells, or 2×107 DoHH2 cells. The xenograft tumors were allowed to grow to an average of 200 mm2. Day 0 refers to the day the tumors were an average of 200 mm2 and when the first/or only dose of treatment was administered, unless indicated specifically below. Tumor volume was calculated based on two dimensions, measured using calipers, and was expressed in mm3 according to the formula: V=0.5a×b2, where a and b are the long and the short diameters of the tumor, respectively. Data collected from each experimental group were expressed as mean±SE. Mice were separated into groups of 8-10 mice with a mean tumor volume between 100-200 mm3, at which point intravenous (i.v.) treatment began. Dosing of antibody or ADC was a single dose of between 2-10 mg/kg of mouse corresponding to a drug concentration of between 200-500 μg/m2 or multiple doses with each dose between 3-10 mg/kg of mouse and a drug concentration of between 200-500 μg/m2 weekly for two to three weeks. The antibody was either an ADC or an unconjugated antibody as a control. Tumors were measured either once or twice a week throughout the experiment. Mice were euthanized before tumor volumes reached 3000 mm3 or when tumors showed signs of impending ulceration. All animal protocols were approved by an Institutional Animal Care and Use Committee (IACUC).
Linkers between the antibody and the toxin that were used were disulfide linker SPP or thioether crosslinker SMCC for DM1 or MC or MC-valine-citrulline(vc)-PAB or (a valine-citrulline (vc)) dipeptide linker reagent)having a maleimide component and a para-aminobenzylcarbamoyl (PAB) self-immolative component for monomethylauristatin E (MMAE) or monomethylauristan F (MMAF). Toxins used were DM1, MMAE or MMAF. TAHO antibodies for this experiment included commercially available antibodies, including commercially available antibodies, anti-human CD79a (TAHO4) (ZL7-4) and anti-human CD79b (TAHO5) (SN8), and antibodies described in Example 9, including anti-human CD79b (TAHO5) (2F2) and anti-human CD79a (TAHO4) (8H9, 5C3, 7H7, 8D11, 15E4 and 16C11) antibodies. Anti-cyno CD79b (TAHO40) (3H3, 8D3, 9H11, and 10D10) described in Example 9 may also be used.
Negative controls included but were not limited to HERCEPTIN® (trastuzumab) based conjugates (SMCC-DM1 or SPP-DM1 or MC-MMAF or MC-vc-PAB-MMAF or MC-vc-PAB-MMAE). Positive controls included but were not limited to free L-DM1 equivalent to the conjugate loading dose.
Summary
(1) Anti-human CD79a (TAHO4)
(a) Ramos Xenografts
In an 18 day time course, anti-human CD79a (TAHO4) antibody conjugated with DM1 (anti-human CD79a-SMCC-DM1) showed inhibition of tumor growth in SCID mice with RAMOS tumors compared to negative control, anti-herceptin-SMCC-DM1. ADC was administered as a single dose at day 0.
In an 18 day time course, anti-CD79a (TAHO4) antibody, including 5C3, 7H7, 8D11, 15E4 and 16C11 antibodies, conjugated with DM1 (anti-human CD79a (5C3, 7H7, 8D11, 15E4 or 16C11)-SMCC-DM1) with a single dose (as indicated in Table 8) administered at day 0 showed inhibition of tumor growth in SCID mice with BJAB-luciferase tumors compared to negative control, HERCEPTIN® (trastuzumab)-SMCC-DM1. ADCs were administered in a single dose (as indicated in Table 11) at day 0 for all ADCs and controls. Specifically, the anti-human CD79a (5C3, 7H7, 8D11, 15E4 or 16C11)-SMCC-DM1 and anti-human CD79b (2F2 or SN8)-SMCC-DM1 significantly inhibited tumor doubling (data not shown). Further, in Table 8, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(c) BJAB Xenografts
In a 14 day time course, anti-human CD79a (TAHO4) antibody, including 8H9 antibodies, and anti-human CD79b (SN8) antibody, conjugated with DM1 (anti-human CD79a (8H9)-SMCC-DM1 and anti-human CD79b (SN8)-SMCC-DM1, respectively) with a single dose (as indicated in Table 12) showed inhibition of tumor growth in SCID mice with BJAB-luciferase tumors compared to negative control, PBS, anti-glycoprotein-120 (herein referred to as “gp120”), anti-human CD79b (SN8), anti-human CD79a (8H9) and anti-gp120 conjugated with DM1 (anti-gp120-SMCC-DM1). ADCs were administered in a single dose (as indicated in Table 9) at day 0 for all ADCs and controls. Specifically, the anti-human CD79a (8H9)-SMCC-DM1 and anti-human CD79b (SN8)-SMCC-DM1 significantly inhibited tumor doubling (data not shown). Further in Table 9, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(2A) Anti-Human CD79b (TAHO5)
Anti-human CD79b (TAHOS) conjugated with DM1 (anti-human CD79b-SMCC-DM1) showed partial regression (PI) or complete remission (CR) in Ramos xenografts with a single dose of the drug conjugate. Further, anti-human CD79b (TAHO5) antibody conjugated with DM1 or MMAF (anti-human CD79b-SMCC-DMI or anti-human CD79b-MC-MMAF) showed partial regression (PI) or complete remission (CR) in BJAB, Granta519 and DoHH2 xenografts with a single dose of the drug conjugate.
(a) Ramos Xenografts
In an 18 day time course, anti-human CD79b (TAHO5) antibody conjugated with DM1 (anti-human CD79b-SMCC-DM1) showed inhibition of tumor growth in SCID mice with RAMOS tumors compared to negative control, anti-herceptin-SMCC-DM1. ADC was administered as a single dose at day 0.
(b) BJAB Xenografts
In a 14 day time course, anti-human CD79b (TAHOS) antibody conjugated with DM1 (anti-human CD79b-SMCC-DM1) showed inhibition of tumor growth in SCID mice with BJAB-luciferase tumors compared to negative control, anti-herceptin-SMCC-DM1 or anti-herceptin antibody. The level of inhibition by anti-human CD79b-SMCC-DM1 antibodies was similar to the level of inhibition by anti-CD20 antibodies. Specifically at day 15, 1 out of 10 mice treated with anti-human CD79b-SMCC-DM1 showed partial regression of tumors and 9 out of 10 mice treated with anti-human CD79b-SMCC-DM1 showed complete regression of tumors. At day 15, 10 out of 10 mice treated with anti-herceptin-SMCC-DM1, anti-herceptin antibody showed tumor incidence. At day 15, 5 out of 10 mice treated with anti-CD20 antibodies showed partial regression of tumors. ADCs were administered in multiple doses (with each dose at the concentration indicated in Table 13) at day 0 and day 5 for all ADCs and controls. An additional treatment of anti-human CD79b-SMCC-DM1 was administered at day 14. Specifically, anti-human CD79b (SN8)-SMCC-DM1 and anti-CD20 significantly inhibited tumor doubling (data not shown). Further, in Table 13, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(c) BJAB Xenografts (MMAE, MMAF, DM1)
In an 80 day time course, anti-human CD79b (TAHO5) antibody (SN8) conjugated with MMAF (anti-human CD79b (SN8)-MC-MMAF or anti-human CD79b (SN8)-MC-vc-PAB-MMAF), DM1 (anti-human CD79b (SN8)-SMCC-DM1) or with MMAE (anti-human CD79b (SN8)-MC-vc-PAB-MMAE) showed inhibition of tumor growth in SCID mice with BJAB-luciferase (Burkitt's lymphoma) tumors compared to negative control, HERCEPTIN® (trastuzumab) conjugated to MMAE or MMAF HERCEPTIN® (trastuzumab)-MC-MMAF), HERCEPTIN® (trastuzumab)-MC-vc-PAB-MMAE and HERCEPTIN® (trastuzumab)-MC-vc-PAB-MMAF). ADCs were administered in a single dose (as indicated in Table 14) at day 0 for all ADCs and controls. Specifically, anti-human CD79b (SN8)-MC-MMAF, anti-human CD79b (SN8)-SMCC-DM1 and anti-CD79b (SN8)-MC-vc-PAB-MMAF significantly inhibited tumor doubling (data not shown). The control HERCEPTIN® (trastuzumab) ADC and anti-human CD79b (SN8) ADC conjugated with MC-vc-PAB-MMAE (HERCEPTIN® (trastuzumab)-MC-vc-PAB-MMAE and anti-human CD79b (SN8)-MC-vc-PAB-MMAE) significantly inhibited tumor doubling (data not shown). Further, in Table 11, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(d) BJAB Xenografts
Even further, in a 30 day time course, anti-human CD79b (TAHO5) antibody (SN8) conjugated with MMAF (anti-human CD79b (SN8) MC-MMAF) or DM1 (anti-human CD79b (SN8)-SMCC-DM1) showed inhibition of tumor growth in SCID mice with BJAB-luciferase (Burkitt's lymphoma) tumors compared to negative control, anti-human CD79b (TAHO5) antibody (SN8), anti-gp120 alone, anti-gp120 conjugated with MMAF (anti-gp120-MC-MMAF) or anti-gp120 conjugated with DM1 (anti-gp120-SMCC-DM1). ADCs were administered in a single dose (as indicated in Table 15) at day 0 for all ADCs and controls. Specifically, anti-human CD79b (SN8)-MC-MMAF and anti-human CD79b (SN8)-SMCC-DM1 significantly inhibited tumor doubling (data not shown) at both drug concentrations 50 ug/m2 and 150 ug/m2. Further, in Table 12, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(e) BJAB Xenografts
Even further, in a 20 day time course, anti-human CD79b (TAHO5) antibody (SN8) conjugated with MMAF (SN8-MC-MMAF) showed inhibition of tumor growth in SCID mice with BJAB-luciferase (Burkitt's lymphoma) tumors compared to negative control, anti-gp120 conjugated with MMAF (anti-gp120-MC-MMAF, anti-gp120-MC-vc-PAB-MMAF) or MMAE (anti-gp120-MC-MMAE). Positive control, anti-CD22, conjugated with MMAE or MMAF was also compared. ADCs were administered in a single dose (as indicated in Table 16) at day 0 for all ADCs and controls. Specifically, anti-human CD79b (SN8)-MC-MMAF ant anti-human CD79b (SN8)-MC-vc-PAB-MMAF and positive controls described above significantly inhibited tumor doubling (data not shown). Both the control anti-gp-120-ADC and anti-human CD79b (SN8) ADC with MC-vc-PAB-MMAE (ant9-gp120-MC-vc-PAB-MMAE and anti-human CD79b (SN8)-MC-vc-PAB-MMAE) significantly inhibited tumor doubling (data not shown). Fvrther, in Table 13, the number of mice out of the total number testqd showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(f) Granta Xenografts
In a 21 day time course, anti-human CD79b (TAHO5) antibody (SN8) conjugated with MMAF (SN88-MC-MMAF) or DM-1 (SN8-SMCC-DM1) showed inhibition of tumor growth in SCID mice with Granta-519 (mantle cell lymphoma) tumors compared to negative control, anti-human CD79b (TAHO5) antibody (SN8), anti-gp120 or anti-gp1220 conjugated with MMAF or DM1 (anti-gp120-MC-MMAF or anti-gp120-SMCC-DM1). A positive control, anti-CD22 antibody (10F4v3) conjugated with MMAF (10F4v3-MC-MMAF) was also compared. ADCs were administered in a single dose (as indicated in Table 17) at day 0 for all ADCs and controls. Specifically, anti-human CD79b (SN8)-SMCC-DM1 and anti-human CD79b (SN8)-MC-MMAF and positive controls described above significantly inhibited tumor doubling at both drug concentrations 100 μg/m2 and 300 μg/m2 (data not shown). Further, in Table 14, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(g) DoHH2 Xenografts
In a 21 day time-course, anti-human CD79b (TAHO5) antibody (SN8) conjugated with MMAF or DM1 (SN8-MC-MMAF or SN8-MC-DM1), or anti-human CD79b (TAHO5) (SN8) alone showed inhibition of tumor growth in SCID mice with DoHH2 (follicular lymphoma) tumors compared to negative control, anti-gp120 or anti-gp1220 conjugated with MMAF or DM1 (anti-gp120-MC-MMAF or anti-gp120-SMCC-DM1). Positive control, anti-CD22 (10F4v3) conjugated to MMAF (anti-CD22 (10F4v3-MC-MMAF) was also compared. ADCs were administered in a single dose (as indicated in Table 18) at day 0 for all ADCs and controls. Specifically, anti-human CD79b (SN8)-SMCC-DM1, anti-human CD79b (SN8)-MC-MMAF significantly inhibited tumor doubling at both drug concentrations 100 μg/m2 and 300 g/m2 (data not shown). Further, in Table 15, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(h) U698M Xenografts
In a 21 day time-course, anti-human CD79b (TAHO5) antibody (SN8) conjugated with DM1 (anti-human CD79b (SN8)-SPP-DM1) showed inhibition of tumor growth in SCID mice with U698M (lymphoblastic lymphosarcoma B cell) tumors compared to negative control, HERCEPTIN® (trastuzumab) conjugated with DM1 (HERCEPTIN® (trastuzumab)-SPP-DM1). ADCs were administered in multiple doses (as indicated in Table 19) at day 2, day 8 and day 15 for all ADCs and controls. Specifically, anti-human CD79b (SN8)-SPP-DM1 significantly inhibited tumor doubling (data not shown). Further, in Table 16, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
(2B) Anti-cyno CD79b (TAHO40)
To test the efficacy of conjugated or unconjugated anti-cyno CD79b (TAHO40) monoclonal antibodies, the effect of anti-TAHO antibody on tumors in mice may be analyzed as described above. Specifically, the ability of the antibodies to regress tumors in multiple xenograft models, including RAJI cells, BJAB cells (Burkitt's lymphoma cell line that contain the t(2;8)(p112;q24) (IGK-MYC) translocation, a mutated p53 gene and are Epstein-Barr virus (EBV) negative) (Drexler, H.G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press, 2001)), Granta 519 cells (mantle cell lymphoma cell line that contains the t(11;14)(q13;q32) (BCL1-IGH) translocation that results in the over-expression of cyclin D1 (BCL1), contains P161NK4B and P161NK4A deletions and are EBV positive) (Drexler, H. G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press, 2001)), and DoHH2 cells (follicular lymphoma cell line that contains the translocation characteristic of follicular lymphoma t(14;18)(q32;q21) that results in the over-expression of Bcl-2 driven by the Ig heavy chain, contains the P161NK4A deletion, contains the t(8;14)(q24;q32) (IGH-MYC) translocation and are EBV negative) (Drexler, H. G., The Leukemia-Lymphoma Cell Line Facts Book, San Diego: Academic Press, 2001)), may be examined.
2. Disseminated Xenografts
To further test the efficacy of conjugated or unconjugated anti-TAHO polypeptide monoclonal antibodies, the effect of anti-TAHO antibody on disseminated tumors in mice were analyzed.
BJAB cells stably expressing luciferase were injected into the tail vein of SCID mice. Bioluminescence imaging was used to monitor tumor progression. On day 10 after cell injection, mice were grouped based on the luminescence signal and treated with ADC. Mice were treated twice (at day 7 and day 14 after injection) with either control ADC HERCEPTIN® (trastuzumab)-SMCC-DM1 (7 mice) or with anti-human CD79b (TAHO5) (SN8) conjugated to DM1 (anti-human CD79b (SN8)-SMCC-DM1) (8 mice) at an antibody dose of 5 mg/kg.
Mice in the control group were euthanized as follows: 2 out of the 7 mice on day 21 and the remaining 5 mice on day 5, because of hind leg paralysis. 1 out of the 8 mice that were treated with anti-human CD79b (SN8)-SMCC-DM1 showed signs of tumor when imaged on day 70 and was euthanized on day 81, but 7 out of the 8 mice treated with anti-human-CD79b (SN8)-SMCC-DM1 were healthy and showed no signs of tumor by day 152. Thus, two doses of anti-human CD79b (SN8)-SMCC-DM1 at an antibody dose of 5 mg/kg eliminated disseminated BJAB tumors in 87% of animals tested.
3. Internalization of B Cell Receptor
To determine the effect of treatment of tumors with ADCs, surface expression of the B cell receptor was analyzed in tumor BJAB xenografts.
For analysis of the surface expression of the B cell receptor, a 13-day time course BJAB xenograft study was initiated as described above, with the following differences. BJAB tumors were allowed to grow to 500 mm2 and at time 0, treated in a single dose (as indicated in Table 19) with anti-human CD79b (TAHO5) (SN8 or 2F2) conjugated to DM1 (anti-human CD79b-SMCC-DM1) or control antibodies, anti-human CD79b (TAHO5) alone (SN8 or 2F2) or anti-gp120 or anti-gp120 conjugated with DM1 (anti-gp120-SMCC-DM1). Two days after treatment with antibodies, two of the tumors were removed for each treatment group and the surface expression of the B cell receptor was examined by flow cytometry.
The remaining tumors not selected for flow cytometry analysis were followed for the remainder of the 13 day time-course. Anti-human CD79b (TAHO5) antibody (SN8 or 2F2) conjugated with DM1 (SN8-SCC-DM1 or 2F2-SMCC-DM1) showed inhibition of tumor growth in SCID mice with BJAB-luciferase tumors compared to negative control, anti-human CD79b (TAHO5) antibody (SN8), anti-human CD79b (TAHO5) (2F2), anti-gp120 or anti-gp1220 conjugated with DM1 (anti-gp120-SMCC-DM1). ADCs were administered in a single dose (as indicated in Table 17) at day 0 for all ADCs and controls. Specifically, anti-human CD79b (SN8 or 2F2)-SMCC-DM1 significantly inhibited tumor doubling (data not shown). Further, in Table 20, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated.
Summary for FACS Analysis
From the FACS analysis, surface expression of CD79a, CD79b and IgM was substantially lower in tumors treated with anti-human CD79b (TAHO5) antibodies (SN8 or 2F2) or anti-human CD79b (TAHO5) antibodies conjugated with DM1 (anti-human CD79b-SMCC-DM1) than in tumors treated with anti-gp120 or anti-gp120 conjugated with DM1 (anti-gp120-SMCC-DM1). Surface expression of CD22 was not affected by treatment with anti-human CD79b (TAHO5) antibodies (SN8 or 2F) or anti-human CD79b (TAHO5) antibodies conjugated with DM1 (anti-human CD79b-SMCC-DM1)
In light of the ability of anti-TAHO antibodies to significantly inhibit tumor doubling in xenografts and disseminated xenografts, TAHO molecules may be excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells. Further, anti-TAHO polypeptide monoclonal antibodies are useful for reducing in vivo tumor growth of tumors, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells.
Even further, efficacy (in xenograft studies described above) of anti-human CD79a (TAHO4) and anti-human CD79b (TAHO5) ADCs did not correlate with surface expression levels of the protein targets nor sensitivity to free drug. Accordingly, anti-TAHO polypeptide monoclonal antibodies may be useful for reducing in vivo tumor growth of tumors with low expression levels of TAHO polypeptide.
To determine tissue expression of TAHO polypeptide and to confirm the microarray results from Example 1, immunohistochemical detection of TAHO polypeptide expression may be examined in snap-frozen and formalin-fixed paraffin-embedded (FFPE) lymphoid tissues, including palatine tonsil, spleen, lymph node and Peyer's patches from the Genentech Human Tissue Bank.
Prevalence of TAHO target expression are evaluated on FFPE lymphoma tissue microarrays (Cybrdi) and a panel of 24 frozen human lymphoma specimens. Frozen tissue specimens are sectioned at 5 μm, air-dried and fixed in acetone for 5 minutes prior to immunostaining. Paraffin-embedded tissues are sectioned at 5 μm and mounted on SuperFrost Plus microscope slides (VWR).
For frozen sections, slides are placed in TBST, 1% BSA and 10% normal horse serum containing 0.05% sodium azide for 30 minutes, then incubated with Avidin/Biotin blocking kit (Vector) reagents before addition of primary antibody. Mouse monoclonal primary antibodies (commercially available) are detected with biotinylated horse anti-mouse IgG (Vector), followed by incubation in Avidin-Biotin peroxidase complex (ABC Elite, Vector) and metal-enhanced diaminobenzidine tetrahydrochloride (DAB, Pierce). Control sections are incubated with isotype-matched irrelevant mouse monoclonal antibody (Pharmingen) at equivalent concentration. Following application of the ABC-HRP reagent, sections are incubated with biotinyl-tyramide (Perkin Elmer) in amplification diluent for 5-10 minutes, washed, and again incubated with ABC-HRP reagent. Detection uses DAB as described above.
FFPE human tissue sections are dewaxed into distilled water, treated with Target Retrieval solution (Dako) in a boiling water bath for 20 minutes, followed by a 20 minute cooling period. Residual endogenous peroxidase activity is blocked using 1× Blocking Solution (KPL) for 4 minutes. Sections are incubated with Avidin/Biotin blocking reagents and Blocking Buffer containing 10% normal horse serum before addition of the monoclonal antibodies, diluted to 0.5-5.0 μg/ml in Blocking Buffer. Sections are then incubated sequentially with biotinylated anti-mouse secondary antibody, followed by ABC-HRP and chromogenic detection with DAB. Tyramide Signal Amplification, described above, is used to increase sensitivity of staining for a number of TAHO targets (CD21, CD22, HLA-DOB).
TAHO molecules may be excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells.
To determine the expression of TAHO molecules, FACS analysis was performed using a variety of cells, including normal cells and diseased cells, such as chronic lymphocytic leukemia (CLL) cells.
A. Normal Cells: TAHO4 (Human CD79a) and TAHO5 (Human CD79b)
For tonsil B cell subtypes, the fresh tonsil was minced in cold HBSS and passed through a 70 um cell strainer. Cells were washed once and counted. CD19+ B cells were enriched using the AutoMACS (Miltenyi). Briefly, tonsil cells were blocked with human IgG, incubated with anti-CD19 microbeads, and washed prior to positive selection over the AutoMACS. A fraction of CD19+ B cells were saved for flow cytometric analysis of plasma cells. Remaining CD19+ cells were stained with FITC-CD77, PE-IgD, and APC-CD38 for sorting of B-cell subpopulations. CD19+ enrichment was analyzed using PE-Cy5-CD19, and purity ranged from 94-98% CD19+. Tonsil B subpopulations were sorted on the MoFlo by Michael Hamilton at flow rate 18,000-20,000 cells/second. Follicular mantle cells were collected as the IgD+/CD38− fraction, memory B cells were IgD−/CD38−, centrocytes were IgD−/CD38+/CD77−, and centroblasts were IgD−/CD38+/CD77+. Cells were either stored in 50% serum overnight, or stained and fixed with 2% paraformaldehyde. For plasma cell analysis, total tonsil B cells were stained with CD138-PE, CD20-FITC, and biotinylated antibody to the target of interest detected with streptavidin-PE-Cy5. Tonsil B subpopulations were stained with biotinylated antibody to the target of interest, detected with streptavidin-PE-Cy5. Flow analysis was done on the BD FACSCaliber, and data was further analyzed using FlowJo software v 4.5.2 (TreeStar). Biotin-conjugated antibodies which were commercially available such as anti-human CD79a (TAHO4) (ZL7-4) and anti-human CD79b (TAHO5) (CB-3) were used in the flow cytometry.
Summary of TAHO4 (Human CD79a) and TAHO5 (Human CD79b) on Normal Cells
The expression pattern on sorted tonsil-B subtypes was performed using monoclonal antibody specific to the TAHO polypeptide of interest. TAHO4 (human CD79a) (using anti-human CD79a) and TAHO5 (human CD79b) (using anti-human CD79b) showed significant expression in memory B cells, follicular mantle cells, centroblasts and centrocytes (data not shown).
The expression pattern on tonsil plasma cells was performed using monoclonal antibody specific to the TAHO polypeptide of interest. TAHO4 (CD79a) (using anti-human CD79a (TAHO4)) and TAHO5 (CD79b) (using anti-human CD79b (TAHO5)) showed significant expression in plasma cells (data not shown).
Accordingly, in light of TAHO4 and TAHO5 expression pattern on tonsil-B subtypes as assessed by FACS, the molecules are excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells.
B. CLL Cells: TAHO4 (Human CD79a) and TAHO5 (Human CD79b)
The following purified or fluorochrome-conjugated mAbs were used for flow cytometry of CLL samples: CD5-PE, CD19-PerCP Cy5.5, CD20-FITC, CD20-APC (commercially available from BD Pharmingen). Further, commercially available biotinylated antibodies against CD22 (RFB4 from Ancell), CD23 (M-L233 from BD Pharmingen), CD79a (ZL7-4 from Serotec or Caltag), CD79b (CB-3 from BD Pharmingen), CD180 (MHR73-11 from eBioscience), CXCR5 (51505 from R&D Systems) were used for the flow cytometry. The CD5, CD19 and CD20 antibodies were used to gate on CLL cells and PI staining was performed to check the cell viability.
Cells (106 cells in 100 l volume) were first incubated with 1 g of each CD5, CD19 and CD20 antibodies and 10 g each of human and mouse gamma globulin (Jackson ImmunoResearch Laboratories, West Grove, Pa.) to block the nonspecific binding, then incubated with optimal concentrations of mAbs for 30 minutes in the dark at 4□C. When biotinylated antibodies were used, streptavidin-PE or streptavidin-APC(Jackson ImmunoResearch Laboratories) were then added according to manufacture's instructions. Flow cytometry was performed on a FACS calibur (BD Biosciences, San Jose, Calif.). Forward scatter (FSC) and side scatter (SSC) signals were recorded in linear mode, fluorescence signals in logarithmic mode. Dead cells and debris were gated out using scatter properties of the cells. Data were analyzed using CellQuest Pro software (BD Biosciences) and FlowJo (Tree Star Inc.).
Summary of TAHO4 (Human CD79a) and TAHO5 (Human CD79b) on CLL Samples
The expression pattern on CLL samples was performed using monoclonal antibody specific to the TAHO polypeptide of interest. TAHO4 (human CD79a) and TAHO5 (human CD79b) showed significant expression in CLL samples (data not shown).
Accordingly, in light of TAHO4 and TAHO5 expression pattern on chronic lymphocytic leukemia (CLL) samples as assessed by FACS, the molecules are excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lymphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells.
Internalization of the TAHO antibodies into B-cell lines was assessed in Raji, Ramos, Daudi and other B cell lines, including ARH77, SuDHL4, U698M, huB and BJAB cell lines.
One ready-to-split 15 cm dish of B-cells (˜50×106 cells) with cells for use in up to 20 reactions was used. The cells were below passage 25 (less than 8 weeks old) and growing healthily without any mycoplasma.
In a loosely-capped 15 ml Falcon tube add 1 μg/ml mouse anti-TAHO antibody to 2.5×106 cells in 2 ml normal growth medium (e.g. RPMI/10% FBS/1% glutamine) containing 1:10 FcR block (MACS kit, dialyzed to remove azide), 1% pen/strep, 5 μM pepstatin A, 10 μg/ml leupeptin (lysosomal protease inhibitors) and 25 μg/ml Alexa488-transferrin (which labeled the recycling pathway and indicated which cells were alive; alternatively Ax488 dextran fluid phase marker were used to mark all pathways) for 24 hours in a 37° C. 5% CO2 incubator. For quickly-internalizing antibodies, time-points every 5 minutes were taken. For time-points taken less than 1 hour, 1 ml complete carbonate-free medium (Gibco 18045-088+10% FBS, 1% glutamine, 1% pen/strep, 10 mM Hepes pH 7.4) was used and the reactions were performed in a 37° C. water bath instead of the CO2 incubator.
After completion of the time course, the cells were collected by centrifugation (1500 rpm 4° C. for 5 minutes in G6-SR or 2500 rpm 3 minutes in 4° C. bench top eppendorf centrifuge), washed once in 1.5 ml carbonate free medium (in Eppendorfs) or 10 ml medium for 15 ml Falcon tubes. The cells were subjected to a second centrifugation and resuspended in 0.5 ml 3% paraformaldehyde (EMS) in PBS for 20 minutes at room temp to allow fixation of the cells.
All following steps are followed by a collection of the cells via centrifugation. Cells were washed in PBS and then quenched for 10 minutes in 0.5 ml 50 mM NH4Cl (Sigma) in PBS and permeablized with 0.5 ml 0.1% Triton-X-100 in PBS for 4 minutes during a 4 minute centrifugation spin. Cells were washed in PBS and subjected to centrifugation. 1 μg/ml Cy3-anti mouse (or anti-species 1° antibody was) was added to detect uptake of the antibody in 200 μl complete carbonate free medium for 20 minutes at room temperature. Cells were washed twice in carbonate free medium and resuspended in 25 μl carbonate free medium and the cells were allowed to settle as a drop onto one well of a polylysine-coated 8-well LabtekII slide for at least one hour (or overnight in fridge). Any non-bound cells were aspirated and the slides were mounted with one drop per well of DAPI-containing Vectashield under a 50×24 mm coverslip. The cells were examined under 100× objective for internalization of the antibodies.
Summary
(1) TAHO4/CD79a (as detected using anti-human CD79a (TAHO4) antibody Serotec ZL7-4 or Caltag ZL7-4) was internalized in 1 hour in Ramos cells, in 1 hour in Daudi cells and in 1 hour in SuDHL4 cells, and was delivered to lysosomes in 3 hours.
(2) TAHO5/CD79b (as detected using anti-human CD79b (TAHO5) antibody Ancell SN8) internalizes in 20 minutes in Ramos, Daudi and Su-DHL4 cells and is delivered to the lysosomes in 1 hour.
Accordingly, in light of TAHO4 and TAHO5 internalization on B-cell lines as assessed by immunofluorescence using respective anti-TAHO antibodies, the molecules are excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells.
To determine where anti-TAHO antibodies are delivered upon internalization into the cell, colocalization studies of the TAHO antibodies internalized into B-cell lines was assessed in Ramos cell lines. LAMP-1 is a marker for late endosomes and lysosomes (Kleijmeer et al., Journal of Cell Biology, 139(3): 639-649 (1997); Hunziker et al., Bioessays, 18:379-389 (1996); Mellman et al., Annu. Rev. Dev. Biology, 12:575-625 (1996)), including MHC class II compartments (MIICs), which is a late endosome/lysome-like compartment. HLA-DM is a marker for MIICs.
Ramos cells were incubated for 3 hours at 37° C. with 1 μg/ml anti-human CD79b (SN8) antibody, FcR block (Miltenyi) and 25 μg/ml Alexa647-Transferrin (Molecular Probes) in complete carbonate-free medium (Gibco) with the presence of 10 μg/ml leupeptin (Roche) and 5 μM pepstatin (Roche) to inhibit lysosmal degradation. Cells were then washed twice, fixed with 3% paraformaldehyde (Electron Microscopy Sciences) for 20 minutes at room temperature, quenched with 50 mM NH4Cl (Sigma), permeabilized with 0.4% Saponin/2% FBS/1% BSA for 20 minutes and then incubated with 1 μg/ml Cy3 anti-mouse (Jackson Immunoresearch) for 20 minutes. The reaction was then blocked for 20 minutes with mouse IgG (Molecular Probes), followed by a 30 minute incubation with Image-iT FX Signal Enhancer (Molecular Probes). Cells were finally incubated with Zenon Alexa488-labeled mouse anti-LAMP1 (BD Pharmingen), a marker for both lysosomes and MIIC (a lysosome-like compartment that is part of the MHC class II pathway), for 20 minutes, and post-fixed with 3% PFA. Cells were resuspended in 20 μl saponin buffer and allowed to adhere to poly-lysine (Sigma) coated slides prior to mounting a coverglass with DAPI-containing VectaShield (Vector Laboratories). For immunofluorescence of the MIIC or lysosomes, cells were fixed, permeabilized and enhanced as above, then co-stained with Zenon labeled Alexa555-HLA-DM (BD Pharmingen) and Alexa488-Lamp1 in the presence of excess mouse IgG as per the manufacturer's instructions (Molecular Probes).
Summary
Anti-human CD79b (TAHO5) (SN8) antibodies colocalized with LAMP1 between 1 and 3 hours of uptake and showed significantly less colocalization with the recycling marker transferrin.
Accordingly, in light of anti-human CD79b (TAHO5) internalization into MIIC or lysosomes of B-cell lines as assessed by immunofluorescence using respective anti-TAHO antibodies, the molecules are excellent targets for therapy of tumors in mammals, including B-cell associated cancers, such as lymphomas (i.e. Non-Hodgkin's Lyphoma), leukemias (i.e. chronic lymphocytic leukemia), myelomas (i.e. multiple myeloma) and other cancers of hematopoietic cells.
Preparation of cysteine engineered anti-TAHO antibodies, such as anti-human CD79b (TAHO5) and anti-cyno CD79b (TAHO40), was performed as disclosed herein.
DNA encoding the chSN8 antibody (light chain, SEQ ID NO: 10,
DNA encoding the anti-cyno CD79b (TAHO40) antibody (ch10D10) (light chain, SEQ ID NO: 41,
In the preparation of the cysteine engineered anti-CD79b antibodies, DNA encoding the light chain was mutagenized to substitute cysteine for valine at Kabat position 205 in the light chain (sequential position 208) as shown in
A. Preparation of Cysteine Engineered Anti-TAHO Antibodies for Conjugation by Reduction and Reoxidation
Full length, cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), monoclonal antibodies (ThioMabs) expressed in CHO cells and purified on a protein A affinity chromatography followed by a size exclusion chromatography. The purified antibodies are reconstituted in 500mM sodium borate and 500 mM sodium chloride at about pH 8.0 and reduced with about a 50-100 fold molar excess of 1 mM TCEP (tris(2-carboxyethyl)phosphine hydrochloride; Getz et al (1999) Anal. Biochem. Vol 273:73-80; Soltec Ventures, Beverly, Mass.) for about 1-2 hrs at 37° C. The reduced ThioMab is diluted and loaded onto a HiTrap S column in 10 mM sodium acetate, pH 5, and eluted with PBS containing 0.3M sodium chloride. The eluted reduced ThioMab is treated with 2 mM dehydroascorbic acid (dhAA) at pH 7 for 3 hours, or 2 mM aqueous copper sulfate (CuSO4) at room temperature overnight. Ambient air oxidation may also be effective. The buffer is exchanged by elution over Sephadex G25 resin and eluted with PBS with 1 mM DTPA. The thiol/Ab value is estimated by determining the reduced antibody concentration from the absorbance at 280 nm of the solution and the thiol concentration by reaction with DTNB (Aldrich, Milwaukee, Wis.) and determination of the absorbance at 412 nm.
After the reduction and reoxidation procedures of Example 17, the cysteine engineered anti-TAHO antibody, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), is reconstituted in PBS (phosphate buffered saline) buffer and chilled on ice. About 1.5 molar equivalents relative to engineered cysteines per antibody of an auristatin drug linker intermediate, such as MC-MMAE (maleimidocaproyl-monomethyl auristatin E), MC-MMAF, MC-val-cit-PAB-MMAE, or MC-val-cit-PAB-MMAF, with a thiol-reactive functional group such as maleimido, is dissolved in DMSO, diluted in acetonitrile and water, and added to the chilled reduced, reoxidized antibody in PBS. After about one hour, an excess of maleimide is added to quench the reaction and cap any unreacted antibody thiol groups. The reaction mixture is concentrated by centrifugal ultrafiltration and the cysteine engineered anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), antibody drug conjugate is purified and desalted by elution through G25 resin in PBS, filtered through 0.2 μm filters under sterile conditions, and frozen for storage.
Preparation of anti-chSN8-HC(A118C) thioMAb-BMPEO-DM1 was performed as follows. The free cysteine on anti-chSN8-HC(A118C) thioMAb was modified by the bis-maleimido reagent BM(PEO)3 (Pierce Chemical), leaving an unreacted maleimido group on the surface of the antibody. This was accomplished by dissolving BM(PEO)3 in a 50% ethanol/water mixture to a concentration of 10 mM and adding a tenfold molar excess of BM(PEO)3 to a solution containing anti-chSN8-HC(A118C) thioMAb in phosphate buffered saline at a concentration of approximately 1.6 mg/ml (10 micromolar) and allowing it to react for 1 hour. Excess BM(PEO)3 was removed by gel filtration (HiTrap column, Pharmacia) in 30 mM citrate, pH 6 with 150 mM NaCl buffer. An approximate 10 fold molar excess DM1 dissolved in dimethyl acetamide (DMA) was added to the anti-chSN8-HC(A118C) thioMAb-BMPEO intermediate. Dimethylformamide (DMF) may also be employed to dissolve the drug moiety reagent. The reaction mixture was allowed to react overnight before gel filtration or dialysis into PBS to remove unreacted drug. Gel filtration on S200 columns in PBS was used to remove high molecular weight aggregates and furnish purified anti-chSN8-HC(A118C) thioMAb-BMPEO-DM1.
By the same protocols, thio control hu-anti-HER2-HC(A118C)-BMPEO-DM1, thio control hu-anti-HER2-HC(A118C)-MC-MMAF and thio control hu-anti-HER2-HC(A118C)-MCvcPAB-MMAE were generated.
By the procedures above, the following cysteine engineered anti-TAHO antibody drug conjugates (TDCs) were prepared and tested:
1. thio anti-cynoCD79b (TAHO40) (ch10D10)-HC(A118C)-MC-MMAF by conjugation of A118C thio anti-cynoCD79b (TAHO40) (ch10D10)-HC(A 118C) and MC-MMAF;
2. thio anti-cynoCD79b (TAHO40) (ch10D10)-HC(A118C)-BMPEO-DM1by conjugation of A118C thio anti-cynoCD79b (TAHO40) (ch10D10)-HC(A118C) and BMPEO-DM1;
3. thio anti-cynoCD79b (TAHO40) (ch10D10)-HC(A118C)-MCvcPAB-MMAE by conjugation of A118C thio anti-cynoCD79b (TAHO40) (ch10D10)-HC(A118C) and MC-val-cit-PAB-MMAE;
4. thio chSN8-HC(A118C)-MC-MMAF by conjugation of thio chSN8-HC(A118C) and MC-MMAF; and
5. thio chSN8-LC(V205C)-MC-MMAF by conjugation of thio chSN8-LC(V205C) and MC-MMAF.
The binding affinity of anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), drug conjugates to a TAHO polypeptide, such as human CD79b (TAHO5) or cynoCD79b (TAHO40), expressed on BJAB-luciferase cells was determined by FACS analysis. Further, the binding affinity of thio anti-cynoCD79b (TAHO40) (ch10D10) drug conjugates to CD79b expressed on BJAB cells expressing cynoCD79b (TAHO40) was determined by FACS analysis.
Briefly, approximately 1×106 cells in 100 μl were contacted with varying amounts (1.0 ug, 01. μg or 0.01 μg of Ab per million cells of BJAB-luciferase cells or BJAB cells expressing cynoCD79b (for anti-cynoCD79b thioMAbs)) of one of the following anti-CD79b thioMAb drug conjugates or naked (unconjugated Ab as a control): (1) thio chSN8-LC(V205C)-MC-MMAF or (2) thio chSN8-HC(A118C)-MC-MMAF (
Anti-CD79b antibody bound to the cell surface was detected using PE conjugated mouse anti-human Ig. The plots of
The in vitro potency of anti-TAHO, such as anti-human CD79b (TAHO5) or anti-cyno CD79b (TAHO40), ThioMAb-drug conjugates, may be measured by a cell proliferation assay. The CellTiter-Glo® Luminescent Cell Viability Assay is a commercially available (Promega Corp., Madison, Wis.), homogeneous assay method based on the recombinant expression of Coleoptera luciferase (U.S. Pat. No. 5,583,024; U.S. Pat. No. 5,674,713; U.S. Pat. No. 5,700,670). This cell proliferation assay determines the number of viable cells in culture based on quantitation of the ATP present, an indicator of metabolically active cells (Crouch et al., J. Immunol. Metho., 160: 81-88 (1993); U.S. Pat. No. 6,602,677). The CellTiter-Glo® Assay is conducted in 96 well format, making it amenable to automated high-throughput screening (HTS) (Cree et al., AntiCancer Drugs, 6:398-404 (1995)). The homogeneous assay procedure involves adding the single reagent (The CellTiter-Glo® Reagent) directly to cells cultured in serum-supplemented medium.
The homogeneous “add-mix-measure” format results in cell lysis and generation of a luminescent signal proportional to the amount of ATP present. The substrate, Beetle Luciferin, is oxidatively decarboxylated by recombinant firefly luciferase with concimatant conversion of ATP to AMP and generation of photons. Viable cells are reflected in relative luminescence units (RLU). Data can be recorded by luminometer or CCD camera imaging device. The luminescence output is presented as RLU, measured over time. % RLU is normalized RLU percentage compared to a “non-drug-conjugate” control. Alternatively, photons from luminescence can be counted in a scintillation counter in the presence of a scintillant. The light units can be represented then as CPS (counts per second).
Efficacy of thioMAb-drug conjugates is measured by a cell proliferation assay employing the following protocol, adapted from CellTiter Glo Luminescent Cell Viability Assay, Promega Corp. Technical bulletin TB288; Mendoza et al., Cancer Res., 62: 5485-5488 (2002)):
1. An aliquot of 40 μl of cell culture containing about 3000 BJAB, Granta-519 or WSU-DLCL2 cells in medium is deposited in each well of a 384-well, opaque-walled plate.
2. TDC (ThioMab Drug Conjugate) (10 μl) is added to quadruplicate experimental wells to final concentration of 10000, 3333, 1111, 370, 123, 41, 13.7, 4.6 or 1.5 ng/mL, with “non-drug conjugate” control wells receiving medium alone, and incubated for 3 days.
3. The plates are equilibrated to room temperature for approximately 30 minutes.
4. CellTiter-Glo Reagent (50 μl) is added.
5. The contents are mixed for 2 minutes on an orbital shaker to induce cell lysis.
6. The plate is incubated at room temperature for 10 minutes to stabilize the luminescence signal.
7. Luminescence is recorded and reported in graphs as % RLU (relative luminescence units). Data from cells incubated with drug-conjugate-free medium are plotted at 0.51 ng/ml.
Media: BJAB, Granta-519 and WSU-DLCL2 cells grow in RPMI1640/10% FBS/2 mM glutamine.
A. Granta-519 (Human Mantle Cell Lymphoma)
In a similar study, using the same xenograft study protocol as disclosed in the Example 12 (see above), varying the drug conjugates and doses administered, the efficacy of thioMAb drug conjugates in Granta-519 xenografts (Human Mantle Cell Lymphoma) in CB17 SCID mice was studied. The drug conjugates and doses (administered at day 0 for all ADCs and controls) are shown in Table 21, below.
The control Ab was hu-anti-HER2-MC-MMAF or chSN8-MC-MMAF. The control HC(A118C) thioMAb was thio hu-anti-HER2-HC(A118C)-MMAF thioMAb. The results are shown in Table 21 and
Further, in the same study, the percent body weight change in the first 14 days was determined in each dosage group. The results (
Even further, in Table 21, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated and NA=not applicable. (DAR=Drug to Antibody Ratio)
B. BJAB-cynoCD79b (TAHO40) Xenografts
In a similar study, using the same xeongraft study protocol as disclosed in Example 12 (see above), varying the drug conjugates and doses administered, the efficacy of thioMAb drug conjugates in BJAB (Burkitt's Lymphoma) cells expressing cynoCD79b (TAHO40) (BJAB-cynoCD79b) xenografts in CB17 SCID was studied. The drug conjugates and doses (administered at day 0 for all ADCs and controls) are shown in Table 22, below.
The control Ab was vehicle (buffer alone). The control thio MAbs were thio-hu-anti-HER2-HC(A118C)-BMPEO-DM1, thio-hu-anti-HER2-HC(A118C)-MC-MMAF and thio-hu-anti-HER2-HC(A118C)-MCvcPAB-MMAE antibody thioMAbs. The results are shown in Table 22 and
Even further, in Table 22, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated and NA=not applicable. (DAR=Drug to Antibody Ratio)
C. BJAB-cynoCD79b (TAHO40) Xenografts
In a similar study, using the same xenograft study protocol as disclosed in Example 12 (see above), varying the drug conjugates and doses administered, the efficacy of thioMAb drug conjugates in BJAB (Burkitt's Lymphoma) expressing cynoCD79b (TAHO40) (BJAB cynoCD79b) xenograft in CB17 SCID mice was studied. The drug conjugates and doses (administered at day 0 for all ADCs and controls) are shown in Table 23, below.
The control thio MAbs was thio-hu-anti-HER2-HC(A118C)-BMPEO-DM1and thio-anti-cynoCD79b (TAHO40) (ch10D10)-HC(A118C) antibody thioMAbs. The results are shown in Table 23 and
The results are shown in Table 23, below. In Table 23, the number of mice out of the total number tested showing PR=Partial Regression (where the tumor volume at any time after administration dropped below 50% of the tumor volume measured at day 0) or CR=Complete Remission (where the tumor volume at any time after administration dropped to 0 mm3) are indicated and NA=not applicable. (DAR=Drug to Antibody Ratio)
Deposit of Material
The following materials have been deposited with the American Type Culture Collection, 10801 University Blvd., Manassas, Va. 20110-2209, USA (ATCC):
These deposits were made under the provisions of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purpose of Patent Procedure and the Regulations there under (Budapest Treaty). This assures maintenance of a viable culture of the deposit for 30 years from the date of deposit. The deposits will be made available by ATCC under the terms of the Budapest Treaty, and subject to an agreement between Genentech, Inc. and ATCC, which assures permanent and unrestricted availability of the progeny of the culture of the deposit to the public upon issuance of the pertinent U.S. patent or upon laying open to the public of any U.S. or foreign patent application, whichever comes first, and assures availability of the progeny to one determined by the U.S. Commissioner of Patents and Trademarks to be entitled thereto according to 35 USC §122 and the Commissioner's rules pursuant thereto (including 37 CFR §1.14 with particular reference to 886 OG 638).
The assignee of the present application has agreed that if a culture of the materials on deposit should die or be lost or destroyed when cultivated under suitable conditions, the materials will be promptly replaced on notification with another of the same. Availability of the deposited material is not to be construed as a license to practice the invention in contravention of the rights granted under the authority of any government in accordance with its patent laws.
The foregoing written specification is considered to be sufficient to enable one skilled in the art to practice the invention. The present invention is not to be limited in scope by the construct deposited, since the deposited embodiment is intended as a single illustration of certain aspects of the invention and any constructs that are functionally equivalent are within the scope of this invention. The deposit of material herein does not constitute an admission that the written description herein contained is inadequate to enable the practice of any aspect of the invention, including the best mode thereof, nor is it to be construed as limiting the scope of the claims to the specific illustrations that it represents. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and fall within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/US2005/018829 | May 2005 | US | national |
This application is a continuation of, and claims priority under 35 USC §120 to U.S. application Ser. No. 12/023,811 filed Jan. 31, 2008, which is a continuation-in-part of, and claims priority under 35 USC §120 to U.S. application Ser. No. 11/462,336, filed Aug. 3, 2006, and wherein U.S. application Ser. No. 11/462,336, filed Aug. 3, 2006 is also a continuation-in-part of, and claims priority under 35 USC §120 to both, PCT Application No. PCT/US2004/038262, filed Nov. 16, 2004, and also to U.S. application Ser. No. 10/989,826, filed Nov. 16, 2004, both of which claim priority under USC §119 to U.S. Provisional Applications, 60/520,842, filed Nov. 17, 2003, and also to 60/532,426, filed Dec. 24, 2003, and wherein PCT Application PCT/US2004/038262, filed Nov. 16, 2004 and U.S. application Ser. No. 10/989,826, filed Nov. 16, 2005, are also both continuations-in-part of and claim priority under USC §120 to both, PCT Application PCT/US03/25892, filed Aug. 19, 2003 and also to U.S. application Ser. No. 10/643,795, filed Aug. 19, 2003, both of which claim priority under USC §119 to U.S. Provisional Application, 60/405,645, filed Aug. 21, 2002, and wherein PCT Application PCT/US03/25892, filed Aug. 19, 2003 and U.S. application Ser. No. 10/643,795, filed Aug. 19, 2003, are also both continuations-in-part of and claim priority under USC §120 to both, PCT Application PCT/US03/11148, filed Apr. 10, 2003 and also to U.S. application Ser. No. 10/411,010, filed Apr. 10, 2003, both of which claim priority under USC §119 to U.S. Provisional Application, 60/378,885, filed May 8, 2002, and wherein the present application also claims priority under 35 USC §120 to both PCT/US2005/018,829, filed May 31, 2005, and also to U.S. application Ser. No. 11/141,344, filed May 31, 2005, both of which claim priority under USC §119 to U.S. Provisional Applications, 60/576,517, filed Jun. 1, 2004, and 60/616,098, filed Oct. 5, 2004, the entire disclosures of which are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60520842 | Nov 2003 | US | |
| 60520842 | Nov 2003 | US | |
| 60532426 | Dec 2003 | US | |
| 60532426 | Dec 2003 | US | |
| 60405645 | Aug 2002 | US | |
| 60405645 | Aug 2002 | US | |
| 60378885 | May 2002 | US | |
| 60378885 | May 2002 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12023811 | Jan 2008 | US |
| Child | 12902434 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11462336 | Aug 2006 | US |
| Child | 12023811 | US | |
| Parent | PCT/US04/38262 | Nov 2004 | US |
| Child | 11462336 | US | |
| Parent | 10989826 | Nov 2004 | US |
| Child | PCT/US04/38262 | US | |
| Parent | PCT/US03/25892 | Aug 2003 | US |
| Child | PCT/US04/38262 | US | |
| Parent | PCT/US03/25892 | Aug 2003 | US |
| Child | 10989826 | US | |
| Parent | 10643795 | Aug 2003 | US |
| Child | PCT/US04/38262 | US | |
| Parent | 10643795 | Aug 2003 | US |
| Child | 10989826 | US | |
| Parent | PCT/US03/11148 | Apr 2003 | US |
| Child | PCT/US03/25892 | US | |
| Parent | PCT/US03/11148 | Apr 2003 | US |
| Child | 10643795 | US | |
| Parent | 10411010 | Apr 2003 | US |
| Child | PCT/US03/25892 | US | |
| Parent | 10411010 | Apr 2003 | US |
| Child | 10643795 | US |
