Patent Application
20230340119
The content of the ASCII text file of the sequence listing named “ARTI906PCT_ST25”, which is 84 kb in size was created on and electronically submitted via EFS-Web Dec. 4, 2020, is incorporated herein by reference in its entirety.
The present disclosure generally relates to the technical field of cancer immunotherapy, and more particularly to composition of modified antibodies with multiple antigen binding specificities.
Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Despite the recent advances in drug discovery and clinical imaging, cancer remains one of the deadliest diseases in humans. Our understandings on how tumor initiates, survives under stress, colonizes/metastasizes to distant organs and sites, and becomes resistant to drugs are still limited. The American Cancer Society estimated new cases of cancer in the US in 2014 is 1.6 million, with no approved curative treatment for most of the predominant types of cancer.
Gastrointestinal (GI) cancers (colorectal, gastric, pancreatic, esophageal, bile duct and liver) are leading causes of morbidity and mortality worldwide. Colorectal carcinoma (CRC) alone represents approximately 10% of all cancer diagnosis and is the second leading cause of cancer deaths world-wide. In China, liver and stomach cancers are among the most lethal of malignancies worldwide and over half of the incidences diagnosed, causing >1.42 million deaths per year globally, which are believed attributable to the viral/bacterial endemic (Hepatitis B virus [HBV] and Helicobacter pylori infections), chemical intoxications, environmental pollutions and food contaminations. There are no effective therapies. New biomarkers and therapeutic targets are thus needed for potential drug development against these aggressive cancers. A proven molecular targeting agent that can eliminate or repress the growth of these cancers will have important clinical value and significant market impact. These tumors can be resected effectively by surgery if the diseases are diagnosed in early stages. Unfortunately, and very often, most of GI cancers are asymptomatic and detected at very advanced stages when presented in the clinic. Without effective treatment, these patients die shortly after the diagnosis or relapse after salvage therapies.
CDH17 is a prominent cancer biomarker characterized by its overexpression in both liver and stomach cancers but not normal tissues from healthy adults. Anti-CDH17 monoclonal antibody displays the growth inhibitory effect on liver and stomach tumour cells. CDH17 is highly expressed in metastatic cancers, and the blockage of CDH17 expression and functions can markedly reduce lung metastasis of hepatocellular carcinoma (HCC). These observations indicate that humanized anti-CDH17 antibody may be developed as target therapeutics for treating cancer patients with indication of CDH17 biomarker in tumour tissues and/or in serum samples. While antibody drug conjugates are promising as an antibody therapy, multi-specific antibody therapeutics take advantage of immune responses to cancer and activate T cell-mediated cytotoxicity to cancer cells.
Bispecific antibodies that target CD3 positive T cells and CD19 positive B cells are proved to be effective for treating hematologic malignancies (Labrijn 2019, Yu 2017, Suurs 2019, and Bates 2019). However, attempts for targeting solid tumours show limited success, possibly due to lack of access to solid tumor cells and suitable immunomodulation signals. There is a need for an antibody-based scaffold for efficient targeting of multiple tumor antigens and immune cell antigens or products to generate more effective immunotherapeutics that better address the complexities of a pro-tumor microenvironment and mechanisms of tumor escape.
In one embodiment, the application provides a multi-specific antibody having a N-terminus and a C-terminus, comprising a first monomer, comprising from the N-terminus to the C-terminus, a VL domain, first linker, and a first Fc domain, a second monomer, comprising from the N-terminus to the C-terminus, a VH domain, a second linker, and a second Fc domain, and at least a first binding domain linked to either the N-terminus or the C-terminus of the multi-specific antibody, wherein the first monomer and the second monomer are paired through the interaction between the VL domain and the VH domain, and wherein the multi-specific antibody is stabilized by a disulfide bond between the first linker and the second linker.
In one embodiment, the first binding domain is linked to the VH domain at the N-terminus, the VL domain at the N-terminus, the first Fc domain at the C-terminus, or the second Fc domain at the C-terminus.
In one embodiment, the multi-specific antibody further includes a second binding domain, and the antibody is tri-specific. In one embodiment, first binding domain is linked to the C-terminus of the first Fc domain and the second binding domain is linked to the C-terminus at the second Fc domain. In one embodiment, first binding domain is linked to the N-terminus at the VH domain and the second binding domain is linked to the C-terminus of the first Fc domain.
In one embodiment, the multi-specific antibody further includes a second binding domain, and the antibody is a tri-specific antibody. In one embodiment, the first binding domain and the second binding domain are linked to the opposite termini of the antibody. In one embodiment, the first binding domain and the second binding domain are linked to the same terminus of the antibody. In one embodiment, the first binding domain is linked to the N-terminus at the VH domain and the second binding domain is linked to the N-terminus at the VL domain.
In one embodiment, the multi-specific antibody further includes a third binding domain, and the antibody is a tetra-specific antibody. In one embodiment, the first binding domain is linked to the N-terminus at the VH domain, the second binding domain is linked to the N-terminus at the VL domain, and the third binding domain is linked to the C-terminus at the first Fc domain or the C-terminus at the second Fc domain.
In one embodiment, the multi-specific antibody above further includes a fourth binding domain, and the antibody is penta-specific. In one embodiment, the third binding domain is linked to the C-terminus at the first Fc domain and the fourth binding domain is linked to the C-terminus at the second Fc domain.
All the binding domains may have the binding affinity toward different antigens. Alternatively, certain binding domain may have the binding affinity toward the same antigen as another binding domain. In one embodiment, the first and the second binding are the same. In one embodiment, the first and the second binding are different. In one embodiment, the first, second and third binding domains are different from each other. In one embodiment, the first, second and third binding domains are different from each other and wherein the fourth binding domain is the same to one of the first, second and third binding domains.
Each first binding domain may be independently selected from a group consisting of a scFv domain, a ligand, a single domain nanobody, the binding region of a natural protein, a chemokine and a cytokine.
In one embodiment, the bi-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 1 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 2.
In one embodiment, the bi-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 1 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 3. In one embodiment, the bi-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 1 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 4. In one embodiment, the bi-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 5 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 6.
In one embodiment, the tri-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 7 and the second monomer c comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 8. In one embodiment, the tri-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 9 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 10. In one embodiment, the tri-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 11 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 2. In one embodiment, the tri-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 12 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 4. In one embodiment, the tri-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 12 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 2.
In one embodiment, the tetra-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 14 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 15.
In one embodiment, the penta-specific antibody may have the first monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 14 and the second monomer comprising an amino acid sequence having at least 98% of sequence identity to SEQ ID NO: 16.
In one embodiment, the binding domains may be attached to the multi-specific antibody through a linker. In one embodiment, the linker comprises a proline-rich amino acid sequence. In one embodiment, the linker may include at least 20%, 30% or 50% of proline residue. In on embodiment, the linker may include from about 2 to about 31 amino acids.
In another aspect, the application provides isolated nucleic acid sequences encoding the multi-specific antibodies as disclosed thereof.
In a further aspect, the application provides expression vectors comprising the isolated nucleic acid sequences as disclosed thereof.
In a further aspect, the application provides a host cell comprising the isolated nucleic acid sequence as disclosed thereof.
In a further aspect, the application provides methods for producing the multi-specific antibodies as disclosed thereof. In one embodiment, the method includes the steps of culturing a host cell such that the DNA sequence encoding the multi-specific antibodies is expressed, and purifying said multi-specific antibody.
In a further aspect, the application provides methods of making the multi-specific antibodies. In one embodiment, the method includes the steps of culturing a host cell under conditions wherein said multi-specific antibodies is produced and recovering said antibody.
In a further aspect, the application provides immunoconjugates. In one embodiment, the immunoconjugate comprises the multi-specific antibody and a cytotoxic agent. In one embodiment, the immunoconjugate comprises the multi-specific antibody and an imaging agent.
In a further aspect, the application provides pharmaceutical compositions. In one embodiment, the pharmaceutical composition includes the multi-specific antibody and a pharmaceutically acceptable carrier. In one embodiment, the pharmaceutical composition may further include radioisotope, radionuclide, a toxin, a therapeutic agent, a chemotherapeutic agent or a combination thereof. In one embodiment, the pharmaceutical composition may include the immunoconjugate as disclosed above and a pharmaceutically acceptable carrier.
In a further aspect, the application provides methods for treating or preventing a cancer in a subject. In one embodiment, the method includes the step of administering to the subject a pharmaceutical composition comprising a purified multi-specific antibody as disclosed herein. In one embodiment, the method of treating a subject with a cancer includes the step of administering to the subject an effective amount of the multi-specific antibody as disclosed herein. In one embodiment, the method may further include co-administering an effective amount of a therapeutic agent. In one embodiment, the therapeutic agent comprises an antibody, a chemotherapy agent, an enzyme, or a combination thereof. The subject may be a human.
In a further aspect, the application provides a solution comprising an effective concentration of the multi-specific antibody as disclosed herein, wherein the solution is blood plasma in a subject.
Embodiments according to the present disclosure may now be described with reference to the figures, in which like reference numerals denote like elements.
In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the Figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.
To enable immunotherapeutics for more effective cancer treatment, especially solid tumors, a combination therapeutic is paramount that incorporates multiple target specificities and/or mechanisms of action beyond that of typical bispecific antibodies. A therapeutic that is essentially a combination treatment such as that described here, is necessary to effectively treat cancer and to more frequently achieve a complete and durable response. Specifically, there is a need for a scaffold that possesses certain properties to create a combination therapeutic with advantageous mechanisms of action, manufacturing, pharmacokinetics, and low antigenic properties relative to approved bispecific antibodies. Many bispecific antibodies that are based on a whole antibody may have a greater mass relative to the tri-specific antibodies described here. While antibodies with a smaller mass, based on antibody fragments, may have greater tumor penetration, they generally possess relatively poor pharmacokinetic properties, such as FDA-approved bispecific antibody Blincyto that does not possess an Fc region. In addition, many bispecific antibodies are based on knob-into-hole possess mutations within the constant domains of the Ig structure, which may contribute to an anti-drug antibody (ADA) response. In this context, a group of modified antibodies described here as Tri-axial or TriAx antibodies, do not require mutations in any constant domain yet have multiple antigen binding specificities.
All formats of TriAx antibodies contain a characteristic core structure comprising a single paired VH and VL (Fv) that defines the first antigen binding specificity while also correctly driving the heterodimerization of the two Fc containing monomers. This core structure is stabilized through the formation of multiple disulphide bonds C-terminal to the Fv region. Minimally a third linker (“triaxial” core) is used to add at least one additional antigen binding region, such as an scFv. A second linker may be added for a second scFv, and so on to increase tumor cell binding specificity or regulate an immune response. These “TriAx” antibodies may be further modified with engineered proline-rich rigid peptide linkers to position binding domains for optimal ligand binding. TriAx antibodies may be composed entirely of human, humanized and low antigenic linker sequences to decrease risk of an ADA response.
TriAx antibodies are designed to bind two or more effector cell receptors to induce two or more mechanisms of anti-tumor activity, for example, T or NK mediated cytotoxicity(CD3, NKG2D), tumor cell phagocytosis (FcR, CR3, CR4, AXL, CD13, CD206) or apoptosis (DR5, i.e. death receptor 5), immune cell stimulation (CD40, OX40), immune checkpoint inhibition (PD-L1, TIGIT, PD1, CTLA4) or conversion of tumor associated macrophages (TAM) from immunosuppressive to inflammatory phenotype (CD206, TREM-2).
The TriAx platform allows for generation of TriAx-A, TriAx-C, TriAx-D, TriAx-E, TriAx-I, and TriAx-J antibodies as shown in
The terms “a”, “an” and “the” as used herein are defined to mean “one or more” and include the plural unless the context is inappropriate.
The term “antibody” is used in the broadest sense and specifically covers single monoclonal antibodies (including agonist and antagonist antibodies), antibody compositions with polyepitopic specificity, as well as antibody fragments, such as Fab, F(ab′)2, and Fv, so long as they exhibit the desired biological activity. In some embodiments, the antibody may be monoclonal, chimeric, single chain, multi-specific, multi-effective, human and humanized antibodies. Examples of active antibody fragments that bind to known antigens include Fab, F(ab′)2, scFv, and Fv fragments, as well as the products of a Fab immunoglobulin expression library and epitope-binding fragments of any of the antibodies and fragments mentioned above. In some embodiments, antibody may include immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, i.e. molecules that contain a binding site that immunospecifically bind to an antigen. The immunoglobulin can be of any type (IgG, IgM, IgD, IgE, IgA and IgY) or class (IgG1, IgG2, IgG3, IgG4, IgA1 and IgA2) or subclasses of immunoglobulin molecule. In one embodiment, the antibody may be whole antibodies and any antigen-binding fragment derived from the whole antibodies. A typical antibody refers to heterotetrameric protein comprising typically of two heavy (H) chains and two light (L) chains. Each heavy chain is comprised of a heavy chain variable domain (abbreviated as VH) and a heavy chain constant domain. Each light chain moiety is comprised of a light chain moiety variable domain (abbreviated as VL) and a light chain moiety constant domain. The VH and VL regions can be further subdivided into domains of hypervariable complementarity determining regions (CDR), and more conserved regions called framework regions (FR). Each variable domain (either VH or VL) is typically composed of three CDRs and four FRs, arranged in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4 from amino-terminus to carboxy-terminus. Within the variable regions of the heavy and light chain there are binding regions that interacts with the antigen.
The term “multi-specific” antibody as used herein denotes an antibody that has at least two binding sites each having a binding affinity to an epitope of an antigen. The term “bi-specific, tri-specific, tetra-specific, or penta-specific” antibody as used herein denotes an antibody that has two, three, four, five, or six antigen-binding sites.
The term “humanized antibody” antibody refers to a type of engineered antibody having its CDRs derived from a non-human donor immunoglobulin, the remaining immunoglobulin-derived parts of the molecule being derived from one (or more) human immunoglobulin(s). In addition, framework support residues may be altered to preserve binding affinity. Methods to obtain “humanized antibodies” are well known to those skilled in the art (see Queen et al., Proc. Natl Acad Sci USA, 1989; Hodgson et al., Bio/Technology, 1991). In one embodiment, the “humanized antibody” may be obtained by genetic engineering approach that enables production of affinity-matured humanlike polyclonal antibodies in large animals such as, for example, rabbits (see U.S. Pat. No. 7,129,084).
The term “antigen” refers to an entity or fragment thereof which can induce an immune response in an organism, particularly an animal, more particularly a mammal including a human. The term includes immunogens and regions thereof responsible for antigenicity or antigenic determinants.
The term “epitope”, also known as “antigenic determinant”, is the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells, and is the specific piece of the antigen to which an antibody binds.
The term “immunogenic” refers to substances which elicit or enhance the production of antibodies, T-cells, or other reactive immune cells directed against an immunogenic agent and contribute to an immune response in humans or animals. An immune response occurs when an individual produces sufficient antibodies, T-cells, and other reactive immune cells against administered immunogenic compositions of the present application to moderate or alleviate the disorder to be treated.
The term “tumor antigen” as used herein means an antigenic molecule produced in tumor cells. A tumor antigen may trigger an immune response in the host. In one embodiment, the tumor cells express tumor antigens, including without limitation, tumor-specific antigens (TSA), neoantigens, and tumor-associated antigens (TAA).
The term “specific binding to” or “specifically binds to” or “specific for” a particular antigen or an epitope as used herein means the binding that is measurably different from a non-specific interaction. Specific binding can be measured 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. Specific binding can be determined by competition with a control molecule that is similar to the target. Specific binding for a particular antigen or an epitope can be exhibited by an antibody having a KD for an antigen or epitope of at least about 10−4 M, at least about 10−5 M, at least about 10−6 M, at least about 10−7 M, at least about 10−8 M, at least about 10−9, alternatively at least about 10−10 M, at least about 10−11 M, at least about 10−12 M, or greater, where KD refers to a dissociation rate of a particular antibody-antigen interaction. In some embodiments, a multi-specific antibody that specifically binds to an antigen will have a KD that is 20-, 50-, 100-, 500-, 1000-, 5,000-, 10,000- or more times greater for a control molecule relative to the antigen or epitope. Also, specific binding for a particular antigen or an epitope can be exhibited by an antibody having a KA or Ka for an antigen or epitope of at least 20-, 50-, 100-, 500-, 1000-, 5,000-, 10,000- or more times greater for the epitope relative to a control, where KA or Ka refers to an association rate of a particular antibody-antigen interaction.
The present disclosure is further described with reference to the following examples. These examples are provided for purposes of illustration only and are not intended to be limiting unless otherwise specified. Those of skill in the art will readily recognize a variety of non-critical parameters that could be changed or modified to yield essentially the same or similar results.
TriAx antibodies are heterodimers that are characterized by a Fv-Fc core structure comprised, from N- to C-terminus, of a Fv region, a modified Ig hinge, and an Ig Fc region as shown in
The TriAx core components include two linkers (e.g. a glycine rich linker fused to a truncated Ig hinge) covalently linking both VH and VL chains of the Fv to the CH2-CH3 monomers. This glycine rich flexible linker to Ig hinge may facilitate efficient VH-VL pairing. The TriAx binding domains may be attached by a flexible glycine rich linker, such as PAGGGGS, or a more rigid proline-rich linker, such as PAGPPP. Linkers may typically be 4 to 7 residues in length. The TriAx Fc may be composed of an IgG1 hinge or an IgG4 hinge with a S228P substitution. The first seven N-terminal amino acids of the IgG1 hinge, EPKSCDK, may be replaced with a glycine rich linker, such as GAPGGGG or PAGGGGS. Hinge residues at position 234 and 235 (G1 numbering) may be LL, FL, or AA to regulate the degree of FcR binding (Saunders 2019). The CH2 and CH3 domains may be all IgG1 or IgG4 or a combination, such as G1 CH2 and G4 CH3. A TriAx molecule may possess a CH3 with substitutions to produce a knob-into-hole (Merchant 1998).
Built on the central TriAx Fv-Fc core structure, TriAx-A is a bivalent antibody format with a single scFv linked to either VH or VL of the Fv, such as h10Ta, h5Ta, h8Ta, and hB2Ta antibodies, whose structural features were listed in Table 1. TriAx-C is a format of trivalent antibody format with the addition of one scFv to the N-terminus of the VH or VL and a second scFv or a protein binding domain at the C-terminus of either CH2-CH3 monomer, such as hC3dh10Tc antibody whose structural features were listed in Table 1. TriAx-D is a trivalent with an scFv linked to the C-terminus of each CH3 of the Fv-Fc core, such as h8C3dTa antibody, whose structural features were listed in Table 1. TriAx-E is a trivalent antibody format with two scFv linked to the VH and VL of the Fv-Fc core, respectively. Examples of TriAx-E antibodies, such as h10Te, h8Te, and h8h10Te, were listed in Table 1 for their structural features and sequence ID. TriAx-I is a format of tetravalent antibodies with the addition of one scFv at the N-terminus of each VH and VL plus one scFv at the C-terminus of either CH2-CH3 monomer. TriAx-J is a pentavalent format with the addition of one scFv at the N-terminus of each VH and VL and at the C-terminus of each CH2-CH3 monomer.
h8Ta is a TriAx-A bi-specific antibody targeting both TROP2 and CD3 (SEQ ID NO: 1 and 4, also see Table 1). TROP2 is a transmembrane glycoprotein that is deregulated in all cancer types independent of baseline levels of TROP2 expression. TROP2 is an ideal candidate for targeted therapeutics. Several TROP2-targeted antibody therapeutics in early-phase clinical trials have demonstrated safety and clinical benefit for treating triple-negative breast cancer, platinum-resistant urothelial cancer, and small-cell lung cancer.
h8Ta was produced in HEK293 cells by PEI co-transfection of a plasmid for heavy (core Fv VH) and light (core Fv Vk) chains. At day 3 post transfection, a sample of culture media was subjected to SDS-PAGE, as shown in
Two TriAx-C antibodies were generated with their binding specificity to a phagocytic receptor CR3. h10Cd3Tc is a TriAx-C tri-specific antibody targeting CDH17, CR3, and CD3 (SEQ ID NO: 7 and 8). h8C3dTd is a TriAx-D trispecific antibody targeting TROP2, CR3 and CD3 (SEQ ID NO: 9 and 10). Both TROP2 and CDH17 are prominent cancer biomarkers characterized by their overexpression in various forms of solid tumors including stomach, colon, pancreatic, liver and liver. CDH17 is highly expressed in metastatic cancers, and the blockage of CDH17 expression and functions can markedly reduce lung metastasis of hepatocellular carcinoma (HCC). Both anti-CDH17 monoclonal antibody and anti-CDH17/CD3 bi-specific antibody display the growth inhibitory effect on liver and stomach tumor cells (see Applicant's application WO/2019/222428, incorporated herein in its entirety). CR3 or complement receptor 3 is a heterodimer of α (CD11b) and β (CD18) transmembrane glycoproteins. The I-domain containing alpha integrin combines with the beta 2 chain (ITGB2) to form a leukocyte-specific integrin referred to as macrophage receptor 1 (‘Mac-1’), or inactivated-C3b (iC3b) receptor 3. During the process of opsonization, C3d is deposited on target cell surfaces where it serves as a macrophage CR3 ligand for phagocytosis. A binding to CR3 via either its ligand, such as C3d, or an activating antibody, may direct a major phagocytic receptor to tumor cells and broadly induce tumor cell phagocytosis and pro-inflammatory macrophage polarization. In this context, the TriAx-C antibodies, such as h8C3dTd and h10C3dTc, can bind either TROP2, CDH17, or both on tumor cells, which then present C3d for macrophage CR3 dependent phagocytosis. The TriAx-C antibodies may also engage FcR, which may further activate and enhance macrophage CR3 tumor cell phagocytosis. These TriAx-C antibodies may broadly target different tumor types enabling greater efficacy and safety relative to targeting a CD47 or CD24 phagocytic checkpoint.
In addition to the anti-CD3 Fv and anti-CDH17 scFv domains, h10Cd3Tc comprises C3d as a CR3 binding domain. When expressed in HEK293 cells, the heavy (core Fv Vh) and light chains (core Fv Vk) of h10Cd3Tc were co-transfected at ratios of 1:1, 4:1, 6:1 and 12:1 (Vh:Vk). Three days post-transfection the levels of antibody expression were determined by Octet (BLI). Production levels were 104 ug/ml (1:1), 27.3 ug/ml (4:1), 22 ug/ml (6:1), 21.7 ug/ml (8:1), and 14.6 ug/ml (12:1). Production culture media samples were subjected to SDS-PAGE. As shown in
The thermal stability of TriAx antibodies was determined in a thermal shift assay using SYPRO orange (King et al. 2011). The TriAx-A antibodies, such as h8Ta (SEQ ID NO: 1 and 4), hB2Ta (SEQ ID NO: 1 and 5), and hA12Ta (SEQ ID NO: 1 and 6) (see Table 1), were analyzed. These TriAx-A antibodies in PBS were centrifuged in a microfuge for 10 minutes, and the concentration was adjusted to 5 uM. A mixture of TriAx-A (50 ul) and SYPRO orange (1 ul) (125× in PBS; 2.5× final) were transferred to an optically clear 96 well plate for assay in a qPCR instrument. The temperature was increased from 25° C. to 99° C. at the rate of 1° C. per minute with a one-minute hold for each measurement with an excitation at 470 nm and emission at 586 nm.
To evaluate the function of TriAx platform antibodies, h8Ta, a TriAx-A bi-specific antibody (see Example 2), was assessed for redirected T cell cytotoxicity. Three luciferase-expressing GI tumor cells lines, DLD1 (colorectal cancer), SW480 (colorectal cancer) and AGS (gastric cancer), were used in a 24-hour assay with an E:T ratio of 4. Following a wash to remove dead cells, viable cells were quantitated using Bio-Glo (Promega) and a multimode plate reader. As shown in
Fibroblast activation protein alpha (FAP) is a 97 kDa, type II cell surface glycoprotein belonging to the serine protease family. In the colorectal cancer (CRC) metastases, the fibroblast activation protein-alpha (FAPα) plays a critical role. It has been reported that in all CRC samples examined, FAPα was expressed in cancer-associated fibroblasts, but not in normal colon, hyperplastic polyps, or adenoma samples.
A TriAx-A bi-specific antibody, hB2Ta (SEQ ID NO: 5 and 6), was generated to target both CD3 (via Fv) and FAP (via scFv). To determine its redirected T cell cytotoxicity activity, FAP mRNA was electroporated into DLD1 cells (DLD1-FAP) that also express luciferase. The following day a microtiter plate cytotoxicity assay was initiated with and without expanded T cells (E:T of 4). After the addition of the antibody at an experimental concentration range in a mixture with either DLD1 or DLD1-FAP, the assay was incubated for 24 hours, followed by a wash, an addition of Bio-Glo substrate and a multimode plate reader that measures the luciferase activity. As shown in
To reduce the risk of off-tumor T cell signaling and the sink to T cells and lymphoid tissues, a low affinity monovalent CD3 binding region, L4 (SEQ ID NO: 13), was introduced into TriAx platform antibodies. CDRs of UCHT1 Vh and Vk (Shalaby 1992) were partially or completely replaced with human germline sequences to generate low affinity and low antigenic anti-CD3 variants. Substitution of Vk CDR1 with IGKV1-33*01 germline sequence resulted in a lower affinity mutant L4, which was incorporated into the core Fv of several TriAx antibodies. Thus, the amino acid sequence of this anti-CD3 variant comprises UCTH1CDR sequences except for CDRL1 substitutions, R24Q and R305, as indicated in
To assess their ability for T cell affinity and activation, the TriAx antibodies having either L4 or its parental Fv Vk CDR1 (“wt”) was determined by flow cytofluorimetry, namely, h10Ta-L4 (SEQ ID NO: 1 and 2) and h10Ta-wt. The antibody binding to peripheral blood T cells was determined for T cell affinity over a range of concentration as shown in
Redirected T cell cytotoxicity was determined for both h10Ta-L4 and h10Ta-wt. In addition, h10Ta-L4c, which was derived from h10Ta-L4 by harboring Vk ACys43 and Vh Q114C substitutions in order to create a stabilizing inter-domain disulfide, was included in the test. T cell killing of a luciferase expressing colon cancer cell line DLD1, and gastric cancer cell line, AGS, was determined over a range of antibody concentrations in a 24-hour assay with an E:T ratio of 4. Following a wash to remove dead cells, viable cells were quantitated using Bio-Glo (Promega) and a multimode plate reader. In the presence of T cells, the EC50 for killing DLD1 was 0.5 pM for h10Ta-wt, 0.4 pM for h10Ta-L4, and 1.2 pM for h10Ta-L4c. The EC50 for AGS killing was 1.4 pM for h10Ta-wt, 2 pM for h10Ta-L4, and 4.7 pM for h10Ta-L4c. These results presented in
h8h10Te (SEQ ID NO: 12 and 2) is a TriAx-E tri-specific antibody comprising both anti-TROP2 (h8) and CDH17 (h10) scFv binding domains at N-terminal of the anti-CD3 core Fv (Table 1). The binding of h8h10Te antibody (possessing the parental anti-CD3 Fv) to all three antigens was demonstrated by flow cytofluorimetry.
With the anti-CD3 binding domain at the Fv position of the TriAx core structure, the addition of one or more binding domains, such as scFv domains, may affect the efficacy of the antibody to bind to cellular CD3. In this regard, TriAx-A antibody, h10Ta (SEQ ID NO: 1 and 2), and a TriAx-E antibody, h10Te, possessing identical anti-CD3 Fv region (wt), were used for comparison. The activity of binding to CD3 was determined by flow cytofluorimetry using 5 ug/ml of each TriAx antibody.
Stabilized versions of TriAx-A scFv specific for TROP2 (h8v5 and h8v6) or CDH17 (h10v3) were generated by back mutating framework residues of the humanized versions h8v4 and h10v2, to enhance the Vh-Vk interface (h8v5, h8v6 and h10v3) and by substituting two residues with cysteine within the Vh domain to create a second disulfide bond (h8v6) (Ewert 2004, McConnell 2012, Weatherill 2012). As shown in
ARB202, a bispecific antibody specific for CDH17 and CD3 with an IgG-scFv format (see Applicant's application WO/2019/222428, incorporated herein in its entirety), was used to compare the stability of 3 proline rich linkers: A=PAGPPA, B=PAGPAP and C=PAGPPP. The linkers extend from the C-terminus of Fc to the N-terminus of anti-CD3 scFv domain. The bispecific antibody (1 mg/ml) was stored at 37° C. in 10mM histidine buffer, pH6.0 for 56 days. At the indicated time points a sample was analyzed for degradation by UPLC. As shown in
h8h10B2Ti (SEQ ID NO: 14 and 15) is an example of tetra-specific TriAx-I antibodies comprising binding specificities to tumor associated antigens, TROP2, CDH17, and FAP (expressed on cancer associated fibroblasts, or CAF). This TriAx-I antibody also binds to CD3 to trigger T cell directed killing of GI cancer cells expressing either TROP2, CDH17, or both, such that the possibility of tumor escape due to loss of tumor target antigen expression may be reduced. By binding to FAP this TriAx-I antibody also directs killing of tumor associated CAF. CAF can be a prominent cell type in the tumor microenvironment that supports tumor growth by promoting extracellular matrix remodeling, angiogenesis and immune suppression.
h8h10B2D5Tj (SEQ ID NO: 14 and 16) is an example of a penta-specific TriAx-J antibodies comprising binding specificities to DR5, in addition to TROP2, CDH17, FAP, DR5 and CD3 as in the TriAx-I antibody, h8h10B2Ti. DR5, also known as death receptor 5, TRAIL receptor 2, and tumor necrosis factor receptor superfamily member 10B, is a cell surface receptor of the TNF-receptor superfamily that binds TRAIL and mediates apoptosis. In this context, h8h10B2D5Tj antibody gains the functions of h8h10B2Ti and exerts an added ability to induce tumor cell apoptosis by engaging DR5 signaling of GI cancer cells.
The above specification and examples provide a complete description of the structure and use of exemplary embodiments. Although certain embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this application. For example, while the above examples may include binding domains at certain positions, they are provided by way of comparison only and not by way of limitation. As such, the illustrative embodiments of the present application are not intended to be limited to the particular embodiments disclosed. Rather, they include all modifications and alternatives falling within the scope of the disclosure. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples having comparable or different properties and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments.
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QKNYLAWYQQKPGQPPKLLVFFAATRESGVPDRFSGSGSGTDETLTISSLQAEDVAVYYCQQHY
STPWTFGGGTKLEIKPAGGGGSEVQLVESGGGLVQPGGSLRLSCAASGYSFTGYTMNWVRQAPG
YSFTDYTMNWVRQAPGQGLEWMGVINPNHGISSYAQKFQGRVTMTRDTSTSTVYMELSSLRSED
This application is a national stage application of international application number PCT/US2020/063461, filed Dec. 4, 2020, which claims the benefit of the filing date of U.S. Provisional Application Ser. No. 62/944,230 filed Dec. 5, 2019 under 35 U.S.C. 119(e), the entire disclosures of which are incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US20/63461 | 12/4/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62944230 | Dec 2019 | US |
