Patent Grant
9328154
The contents of the text file submitted electronically herewith are incorporated herein by reference in their entirety: A computer readable format copy of the Sequence Listing (filename: PHAS_021_04US_SeqList_ST25.txt, date recorded: Apr. 14, 2014, file size 50 kb).
Therapeutic proteins or peptides in their native state or when recombinantly produced can be labile molecules exhibiting, inter alia, short periods of serum stability, serum half-life (i.e., circulatory half-life), or limited persistence in the body. Such molecules can also be extremely labile when formulated, such as when formulated in aqueous solutions.
In some instances, polyethylene glycol (PEG) conjugated to a proteinaceous molecule results in a longer-acting, sustained activity of the molecule. PEG attachment, however, can often substantially reduce or even destroy the protein's therapeutic activity. Therapeutic proteins and/or peptides have also been stabilized by fusion to certain proteins that are capable of extending serum half-life. For example, in some instances, therapeutic proteins fused to albumin, transferrin, and antibody fragments exhibit extended serum half-life when compared to the therapeutic protein in the unfused state. See U.S. Pat. No. 7,238,667 (particularly with respect to albumin conjugates), U.S. Pat. No. 7,176,278 (particularly with respect to transferrin conjugates), and U.S. Pat. No. 5,766,883, which are each hereby incorporated by reference in their entireties.
There remains a need in the art for more stable, longer acting, and/or effective proteinaceous molecules.
The present invention provides therapeutic agents comprising an elastic peptide component and a therapeutic proteinacious component. The elastic peptide component may form a spiral conformation, and/or may have an extended structure relative to an alpha helix. The elastic peptide component may be structurally related to, or derived from, sequences of the elastin protein (elastin-like-peptide or ELP). Such elastic peptide components provide certain therapeutic advantages to the therapeutic agent, such as comparatively better stability, solubility, bioavailability, half-life, persistence, and/or biological action of the therapeutic proteinaceous component. Such properties may be determined, for example, with respect to the therapeutic component's unfused or unconjugated counterpart. In some embodiments, the elastic peptide is an ELP that undergoes a reversible inverse phase transition, which may impart additional practical and/or therapeutic advantages. The invention further provides polynucleotides encoding the therapeutic agents of the invention, as well as methods of treatment or prophylaxis for certain biological conditions.
In a first aspect, the invention provides a therapeutic agent comprising an elastic peptide component and a therapeutic proteinacious component, as well as pharmaceutical compositions containing the same for delivery to a subject or patient in need. The therapeutic component may be selected from active portions of the therapeutic proteins described herein, including those listed in Table 1, or functional analogs thereof. In certain embodiments, the therapeutic component is a GLP-1 receptor agonist, such as GLP-1, exendin-4, or a functional analog thereof. Such therapeutic components are generally effective for, among other things, increasing insulin secretion from the pancreas in a glucose-dependent manner. In other embodiments, the therapeutic component is an insulin or functional analog thereof, which is generally effective for promoting glucose uptake from the blood and storage within cells. In still other embodiments, the therapeutic component is a Factor VII/VIIa or functional analog thereof, which is generally effective for promoting coagulation by activation of Factor X or Factor IX.
The elastic peptide and therapeutic components may be covalently coupled by various means, including chemical coupling (e.g., conjugation) and recombinant fusion technology. In addition, the number of elastic peptide or therapeutic components per molecule, and their respective positions within the molecule, may vary as needed. The therapeutic agent may further include one or more spacer or linker moieties, which in addition to providing the desired functional independence of the elastic peptide and therapeutic components, may optionally provide for additional functionalities, such as a protease-sensitive feature to allow for proteolytic release or activation of the therapeutic component. The therapeutic agent may further include one or more targeting components such as, for example, a peptide or protein to target the therapeutic agent to a particular cell type, e.g., a cancer cell, or to a particular organ.
In a second aspect, the invention provides polynucleotides, such polynucleotides comprising a nucleotide sequence encoding a therapeutic agent of the invention. For example, the nucleotide sequence encodes an elastic peptide fusion with a functional portion of at least one therapeutic protein described herein, including those listed in Table 1 (or functional analog thereof). In certain embodiments, the therapeutic component is a GLP-1 receptor agonist (including GLP-1 and exendin-4), insulin, Factor VII/VIIa, or functional analog thereof. Such polynucleotides may further comprise additional control element(s) operably linked to the nucleotide sequence, such as promoter elements and/or other transcription or expression-related signals. The polynucleotide may be inserted into various vectors, which may be useful for production of the therapeutic agent in host cells, including, for example, bacterial and eukaryotic host cells.
In a third aspect, the invention provides a method for treating or preventing a disease, disorder, or condition in a subject, such as in a mammalian patient, including a human patient. The method comprises administering an effective amount of the therapeutic agent of the invention (or pharmaceutical composition containing the same) to a subject or patient in need thereof. For example, the patient may be in need of an agent having a biological activity or preferred indication listed herein (e.g., in Table 1). In certain embodiments employing a GLP-1 receptor agonist/elastic peptide compound or employing an insulin/elastic peptide compound, the invention provides a method for treating one or more disorders including type 1 or type 2 diabetes, hyperglycemia, and impaired glucose tolerance. In certain other embodiments employing Factor VII/VIIa/elastic peptide compound, the invention provides a method for treating one or more disorders including hemophilia, post-surgical bleeding, anticoagulation-induced bleeding, thrombocytopenia, factor VII deficiency, factor XI deficiency, and intracranial hemorrhage.
Various other aspects, features and embodiments of the invention will be more fully apparent from the following disclosure and appended claims.
The present invention provides therapeutic agents comprising an elastic peptide component and a therapeutic component. The therapeutic component may be selected from Table 1 (e.g., selected from a Therapeutic Protein, or functional portion or functional analog thereof, listed in Table 1), or described herein. In certain embodiments, the therapeutic component is a GLP-1 receptor agonist, such as GLP-1 or exendin-4, or may be insulin, Factor VII/VIIa, or functional analog thereof. The elastic peptide component exhibits a flexibility and freedom of movement that results from its secondary structure characteristics, and overall or substantial lack of a rigid tertiary structure. The elastic peptide components may contain structural units related to, or derived from, sequences of the elastin protein. The elastic peptide provides certain therapeutic advantages, such as comparatively better persistence, stability, solubility, bioavailability, half-life, and/or biological action of the therapeutic component. Such properties may be determined with respect to, for example, an unfused or unconjugated counterpart of the therapeutic component. The invention further provides polynucleotides encoding the therapeutic agents of the invention, as well as methods of treatment or prophylaxis for certain biological conditions, including the preferred indications listed in Table 1, and including diabetes (e.g., Type I and Type II), hyperglycemia, bleeding, hemophilia, and hemorrhage, among others.
For ease of reference in the ensuing discussion, set out below are definitions of some terms appearing in the discussion.
As used herein, the term “therapeutic agent” or “therapeutic component” refers to an agent or component capable of inducing a biological effect in vivo and/or in vitro. The biological effect may be useful for treating and/or preventing a condition, disorder, or disease in a subject or patient.
As used herein, the term “coupled” means that the specified components are either directly covalently bonded to one another (e.g., via chemical conjugation or recombinant fusion technology), or indirectly covalently joined to one another (e.g., via chemical conjugation or recombinant fusion technology) through an intervening moiety or moieties, such as a bridge, spacer, or linker.
As used herein, “half-life” (which generally refers to in vivo half-life or circulatory half-life) is the period of time that is required for a 50% diminution of bioactivity of the active agent to occur. Such term is to be contrasted with “persistence,” which is the overall temporal duration of the active agent in the body, and “rate of clearance” as being a dynamically changing variable that may or may not be correlative with the numerical values of half-life and persistence.
The term “functional analog” refers to a protein that is an active analog (e.g., either chemical or protein analog), derivative, fragment, truncation isoform or the like of a native protein. For example, the functional analog may be a functional analog of a therapeutic protein listed in Table 1, or may be a functional analog of a GLP-1 receptor agonist (e.g., GLP-1, exendin), insulin, or Factor VII/VIIa. A polypeptide is active when it retains some or all of the biological activity of the corresponding native polypeptide, as determined in vivo or in one or more indicative in vitro assays. Exemplary activity assays for certain therapeutic proteins, which are determinative of activity, are listed Table 1. Further, such biological activities and assays for GLP-1 receptor agonists, insulin, and Factor VII/VIIa, which are determinative of whether a given molecule is a “functional analog,” are described in detail elsewhere herein.
As used herein, the term “native,” as used in reference to an amino acid sequence, indicates that the amino acid sequence is found in a naturally-occurring protein.
As used herein, the term “spacer” refers to any moiety, peptide or other chemical entity, that may be interposed between the elastic peptide component and the therapeutic component. For example, the spacer may be a divalent group that is covalently bonded at one terminus to the elastic peptide component, and covalently bonded at the other terminus to the therapeutic component. The therapeutic agents may therefore be open to the inclusion of additional chemical structure that does not preclude the efficacy of the agent for its intended purpose. The spacer may, for example, be a protease-sensitive spacer moiety that is provided to control the pharmacokinetics of the agent, or the spacer may be a protease-resistant moiety.
The therapeutic component and the elastic peptide component may be coupled with one another in any suitable covalent manner, including chemical coupling and recombinant technology, such that the therapeutic agent is efficacious for its intended purpose, and such that the presence of the elastic peptide component enhances the therapeutic component in some functional, therapeutic or physiological aspect. For example, the elastic peptide-coupled therapeutic component may be enhanced in, e.g., its bioavailability, bio-unavailability, therapeutically effective dose, biological action, formulation compatibility, resistance to proteolysis or other degradative modality, solubility, half-life or other measure of persistence in the body subsequent to administration, rate of clearance from the body subsequent to administration, etc. Such enhancement may be determined, for example, in relation to a corresponding unconjugated or unfused counterpart therapeutic (e.g., determined relative to native GLP-1, exendin, insulin, or Factor VII/VIIa, or a therapeutic protein described herein).
In some embodiments, the therapeutic agent of the invention circulates or exists in the body in a soluble form, and escapes filtration by the kidney thereby persisting in the body in an active form. In some embodiments, the therapeutic agents of the invention have a molecular weight of less than the generally recognized cut-off for filtration through the kidney, such as less than about 60 kD, or in some embodiments less than about 55, 50, 45, 40, 30, or 20 kDa, and persist in the body by at least 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 20-fold, or 100-fold or longer than an uncoupled (e.g., unfused or unconjugated) therapeutic counterpart.
The number of elastic peptide and/or therapeutic components per molecule, and their respective positions within the molecule, may vary among embodiments of the invention. For example, in embodiments where the agent is a recombinant fusion, at least one elastic peptide component may be placed at one or both of the N-terminus and the C-terminus. Where the elastic peptide component is at both the N-terminus and C-terminus of the fusion, the elastic peptide components will flank the therapeutic component. Alternatively, the therapeutic component may be positioned at either or both of the N-terminus and C-terminus. Where the therapeutic component is at both the N-terminus and C-terminus, the therapeutic component will flank the elastic peptide component. In a further embodiment, different therapeutic components are positioned at the N-terminus and C-terminus of the molecule. As discussed in detail herein, in certain embodiments, such therapeutic component(s) may be released by proteolysis of a spacer moiety separating the elastic peptide and therapeutic components. In certain embodiments, the therapeutic component may be inactive in the fused state, and becoming active upon proteolytic release from the elastic peptide component(s). Alternatively, the therapeutic component remains active in the fused state, making proteolytic processing of the therapeutic agent unnecessary for biological activity.
When prepared as recombinant fusions, the therapeutic agent can be prepared by known recombinant expression techniques. For example, to recombinantly produce the therapeutic agent, a nucleic acid sequence encoding the chimeric gene is operatively linked to a suitable promoter sequence such that the nucleic acid sequence encoding such fusion protein will be transcribed and/or translated into the desired fusion protein in the host cells. Preferred promoters are those useful for expression in E. coli, such as the T7 promoter. Any commonly used expression system may be used, including eukaryotic or prokaryotic systems. Specific examples include yeast (e.g., Saccharomyces spp., Pichia spp.), baculovirus, mammalian, and bacterial systems, such as E. coli, and Caulobacter.
The various aspects and embodiments of the invention are described in greater detail in the following sections.
Elastic Peptide Component
The therapeutic agent of the invention may comprise one or more elastic peptide components. The elastic peptide components may comprise or consist of structural peptide units or sequences that are related to, or derived from, the elastin protein (e.g., elastin-like-peptides, or ELPs). Elastic peptides are useful for improving the properties of therapeutic proteins, such as those described herein (e.g., listed in Table 1), including GLP-1 receptor agonists (e.g., GLP-1 or exendin-4), insulin, and Factor VII/VIIa in one or more of bioavailability, therapeutically effective dose, biological action, formulation compatibility, resistance to proteolysis, solubility, half-life or other measure of persistence in the body subsequent to administration, and/or rate of clearance from the body.
The elastic peptide component may be constructed from structural units of from three to about twenty amino acids, or in some embodiments, from four to ten amino acids, such as five or six amino acids. The length of the individual structural units, may vary or may be uniform. In certain embodiments, the elastic peptide component is constructed of a polytetra-, polypenta-, polyhexa-, polyhepta-, polyocta, and polynonapeptide motif of repeating structural units. Exemplary structural units include units defined by SEQ ID NOS: 1-12 (below), which may be employed as repeating structural units, including tandem-repeating units, or may be employed in some combination, to create a peptide component effective for improving the properties of the therapeutic component. Thus, the elastic peptide component may comprise or consist essentially of structural unit(s) selected from SEQ ID NOS: 1-12, as defined below.
The elastic peptide component, comprising such structural units, may be of varying sizes. For example, the elastic peptide component may comprise or consist essentially of from about 10 to about 500 structural units, or in certain embodiments about 15 to about 150 structural units, or in certain embodiments from about 20 to about 100 structural units, or from about 50 to about 90 structural units, including one or a combination of units defined by SEQ ID NOS: 1-12. Thus, the elastic peptide component may have a length of from about 50 to about 2000 amino acid residues, or from about 100 to about 600 amino acid residues, or from about 200 to about 500 amino acid residues, or from about 200 to about 400 amino acid residues.
Elastic polymers (e.g., bioelastic polymers) are known and described in, for example, U.S. Pat. No. 5,520,672 to Urry et al. In general, elastic peptides comprise elastomeric units of bioelastic pentapeptides, tetrapeptides, and/or nonapeptides (e.g., elastin-like peptides). Thus, in some embodiments the elastomeric unit is a pentapeptide, in other embodiments the elastomeric unit is a tetrapeptide, and in still other embodiments the elastomeric unit is a nonapeptide. Bioelastic polymers that may be used to carry out the present invention are set forth in U.S. Pat. No. 4,474,851, which is hereby incorporated by reference in its entirety.
As disclosed in U.S. Pat. No. 4,474,851, elastomeric peptides may have a sequence of regularly appearing β-turns, forming an overall spiral conformation (e.g., a β-spiral, which is a series of regularly repeating β-turns). The spiral structures are more open than the more common α-helix. As a result, the atoms in the peptide backbone have a high freedom of movement (e.g., as compared to the freedom of movement for an α-helix). This is particularly true of librational motions involving peptide moieties. A libration is a torsional oscillation involving simultaneous rotational motions of the two single bonds on each side of a librating moiety. The moiety involved in a libration may be a single peptide bond or several peptide residues. For adequate freedom of motion to exist, it is important, however, that the carbonyl oxygen and the amino hydrogen of the peptide bond not be involved in hydrogen bonding to other parts of the molecule or to other molecules. Otherwise a greater energy barrier to the libration exists and motion will be restricted. Since non-hydrogen-bonded segments having freedom of motion exist in the β-spiral between the points of hydrogen bonding for the β-turns, these segments may be said to be librationally suspended. Librationally suspended segments therefore are a structural feature that exists in certain elastic peptides because of the repeating β-turns with relative infrequent hydrogen bonding. Librationally suspended segments resulting from the β-spiral structure are thought to give rise to elasticity, as will be further discussed.
Another factor leading to the high librational freedom of such molecules is the absence of significant polar interactions between the amino acid residues, either intrachain or interchain, other than a hydrogen bond within the β-turn. The amino acid residues present are mostly hydrophobic or glycine and accordingly do not exert significant forces on one another through space. If a significant number of charged or polar groups were present, electrostatic interactions might limit librational freedom and restrict the number of available states in the relaxed (non-extended) form of the molecules. Polar and charged amino acid residues are not strictly prohibited, however, if their presence does not destroy the elasticity of the eslatic peptide component as a whole. For example, an occasional serine residue is present in naturally occurring tropoelastin without destroying elasticity. Accordingly, hydrophobic amino acid residues and glycines are preferred in forming elastomeric polypeptides of the present type although other amino acids may be present to a some extent.
Although not intending to be bound by theory, the elasticity of polypeptides of the β-turn structure may be caused by thermodynamic drive toward greater entropy. The relaxed state of the β-spiral has a large degree of librational freedom and thus the atoms of the peptide chain can exist in a large number of positions. When the molecules are stretched, the degree of freedom is reduced, particularly for librational motions, and when the tension is released, a thermodynamic driving force toward higher entropy results in reformation of the contracted β-spiral.
Other specific bioelastic polymers that can be used to carry out the present invention are described in U.S. Pat. Nos. 4,132,746, 4,187,852, 4,500,700, 4,589,882, and 4,870,055, each of which are hereby incorporated by reference. Still other examples of bioelastic polymers are set forth in U.S. Pat. No. 6,699,294, U.S. Pat. No. 6,753,311, and U.S. Pat. No. 6,063,061, which are also incorporated by reference in their entirety.
In some embodiments, the β-turn may have the following structure, in the formation of a β-spiral:
wherein R1-R5 represent side chains of amino acid residues 1-5, and m is 0 when the repeating unit is a tetrapeptide or 1 when the repeating unit is a pentapeptide. Nonapeptide repeating units generally consist of sequential tetra- and pentapeptides. The amino acid residues may be hydrophobic amino acid residues, such as those independently selected from alanine, valine, leucine, isoleucine, proline, phenylalanine, tryptophan, and methionine. In many cases, the first amino acid residue of the repeating unit is a residue of valine, leucine, isoleucine or phenylalanine; the second amino acid residue is a residue of proline; the third amino acid residue is a residue of glycine; and the fourth amino acid residue is glycine or a hydrophobic residue such as tryptophan, phenylalanine or tyrosine.
In some embodiments, the elastic peptide component, or in some cases the therapeutic agent, has a size of less than about 65 kDa, or less than about 60 kDa, or less than about 55 kDa, or less than about 50 kDa, or less than about 40 kDa, or less than about 30 or 25 kDa. Three major blood proteins, Human Serum Albumin (HSA), Transferrin (Tf) and IgG, or the Fc portion of IgGs in their glycosylated form, have been exploited to extend the half-lives of proteins and peptides for improved therapeutic use. These molecules are 585, 679 and 480 amino acids in length giving molecular weights of about 66, 77, and ˜75 kDa (including glycosylations), respectively. They are each globular and relatively compact. The half life of these molecules is determined by a number of factors, including charge distribution, rescue of molecules by the neonatal Fc receptor (FcRn) (HSA and Fc) or cycling of Tf through the Tf receptor (TfR), and their size which prevents filtering through the kidney glomerulus. HSA is slightly below the generally regarded cut-off for filtration through the kidney (˜70 kDa) but its charge distribution helps prevent this. It would be anticipated that, in order to achieve half-life extension of the same order as that achieved with HSA, Tf and Fc, a protein of at least this molecular weight range would be required or desirable, i.e. having over 550 amino acids and being over 65 kDa. However, an elastic peptide with a small number of amino acids relative to HSA, Tf and Fc (e.g., in the range of about 300 to 400) and around 30 to 40 kDa may have a half life that matches and/or exceeds that of HSA, Tf, and Fc.
Thus, in some embodiments, the elastic peptide component may have an extended, relatively unstructured (e.g., no definitive tertiary structure due to rotational and/or librational freedom of the peptide backbone) and non-globular form, and thus such molecules may have a large expanded structure in comparison to HSA, Tf and Fc, so as to escape kidney filtration. In such embodiments, the therapeutic agents of the invention have a molecular weight of less than the generally recognized cut-off for filtration through the kidney, such as less than about 60 kD, or in some embodiments less than about 55, 50, 45, 40, 30, or 25 kDa, and persist in the body by at least 2-fold, 3-fold, 4-fold, 5-fold, 10-fold, 20-fold, or 100-fold longer than an uncoupled (e.g., unfused or unconjugated) therapeutic counterpart.
In certain embodiments, the elastic peptide component is an ELP that undergoes a reversible inverse phase transition. ELP components are structurally disordered and highly soluble in water below a transition temperature (Tt), but exhibit a sharp (2-3° C. range) disorder-to-order phase transition when the temperature is raised above the Tt, leading to desolvation and aggregation of the ELP components. For example, the ELP forms insoluble polymers, when reaching sufficient size, which can be readily removed and isolated from solution by centrifugation. Such phase transition is reversible, and isolated insoluble ELPs can be completely resolubilized in buffer solution when the temperature is returned below the Tt of the ELPs. Thus, the therapeutic agents of the invention can, in some embodiments, be separated from other contaminating proteins to high purity using inverse transition cycling procedures, e.g., utilizing the temperature-dependent solubility of the therapeutic agent, or salt addition to the medium. Successive inverse phase transition cycles can be used to obtain a high degree of purity. In addition to temperature and ionic strength, other environmental variables useful for modulating the inverse transition of the therapeutic agents include pH, the addition of inorganic and organic solutes and solvents, side-chain ionization or chemical modification, and pressure.
In certain embodiments, the ELP component does not undergo a reversible inverse phase transition, or does not undergo such a transition at a biologically relevant Tt, and thus the improvements in the biological and/or physiological properties of the molecule (as described elsewhere herein), may be entirely or substantially independent of any phase transition properties. Nevertheless, such phase transition properties may impart additional practical advantages, for example, in relation to the recovery and purification of such molecules.
In certain embodiments, the ELP component(s) may be formed of structural units, including but not limited to:
In certain embodiments, the ELP component(s) contain repeat units, including tandem repeating units, of the pentapeptide Val-Pro-Gly-X-Gly (SEQ ID NO:3), where X is as defined above, and where the percentage of Val-Pro-Gly-X-Gly (SEQ ID NO:3) pentapeptide units taken with respect to the entire ELP component (which may comprise structural units other than VPGXG (SEQ ID NO:3)) is greater than about 75%, or greater than about 85%, or greater than about 95% of the ELP component. The ELP component may contain motifs having a 5 to 15-unit repeat (e.g. about 10-unit repeat) of the pentapeptide of SEQ ID NO: 3, with the guest residue X varying among at least 2 or at least 3 of the units. The guest residues may be independently selected, such as from the amino acids V, I, L, A, G, and W (and may be selected so as to retain a desired inverse phase transition property). The repeat motif itself may be repeated, for example, from about 5 to about 12 times, such as about 8 to 10 times, to create an exemplary ELP component. The ELP component as described in this paragraph may of course be constructed from any one of the structural units defined by SEQ ID NOS: 1-12, or a combination thereof.
In some embodiments, the ELP component may include a β-turn structure. Exemplary peptide sequences suitable for creating a β-turn structure are described in International Patent Application PCT/US96/05186, which is hereby incorporated by reference in its entirety. For example, the fourth residue (X) in the elastin pentapeptide sequence, VPGXG (SEQ ID NO:3), can be altered without eliminating the formation of a β-turn. Alternatively, the ELP component may lack a β-turn, or otherwise have a different conformation and/or folding character.
In certain embodiments, the ELP components include polymeric or oligomeric repeats of the pentapeptide VPGXG (SEQ ID NO: 3), where the guest residue X is any amino acid. X may be a naturally occurring or non-naturally occurring amino acid. In some embodiments, X is selected from alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tryptophan, tyrosine and valine. In some embodiments, X is a natural amino acid other than proline or cysteine.
The guest residue X (e.g., with respect to SEQ ID NO: 3, or other ELP structural unit) may be a non-classical (non-genetically encoded) amino acid. Examples of non-classical amino acids include: D-isomers of the common amino acids, 2,4-diaminobutyric acid, α-amino isobutyric acid, A-aminobutyric acid, Abu, 2-amino butyric acid, γ-Abu, ε-Ahx, 6-amino hexanoic acid, Aib, 2-amino isobutyric acid, 3-amino propionic acid, ornithine, norleucine, norvaline, hydroxyproline, sarcosine, citrulline, homocitrulline, cysteic acid, t-butylglycine, t-butylalanine, phenylglycine, cyclohexylalanine, β-alanine, fluoro-amino acids, designer amino acids such as β-methyl amino acids, Ca-methyl amino acids, Nα-methyl amino acids, and amino acid analogs in general.
Selection of X is independent in each ELP structural unit (e.g., for each structural unit defined herein having a guest residue X). For example, X may be independently selected for each structural unit as an amino acid having a positively charged side chain, an amino acid having a negatively charged side chain, or an amino acid having a neutral side chain, including in some embodiments, a hydrophobic side chain.
In still other embodiments, the ELP component(s) may include polymeric or oligomeric repeats of the pentapeptides VPGXG (SEQ ID NO:3), IPGXG (SEQ ID NO:5) or LPGXG (SEQ ID NO:7), or a combination thereof, where X is as defined above.
In each embodiment, the structural units, or in some cases polymeric or oligomeric repeats, of the elastic peptide sequences may be separated by one or more amino acid residues that do not eliminate the overall effect of the molecule, that is, in imparting certain improvements to the therapeutic component as described. In certain embodiments, such one or more amino acids also do not eliminate or substantially affect the phase transition properties where ELP components are employed (relative to the deletion of such one or more amino acids).
For ELP sequences, in each repeat, X is independently selected. The structure of the resulting ELP components may be described using the notation ELPk [XiYj n], where k designates a particular ELP repeat unit, the bracketed capital letters are single letter amino acid codes and their corresponding subscripts designate the relative ratio of each guest residue X in the structural units (where applicable), and n describes the total length of the ELP in number of the structural repeats. For example, ELP1 [V5A2G3-10] designates an ELP component containing 10 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is valine, alanine, and glycine at a relative ratio of 5:2:3; ELP1 [K1V2F1-4] designates an ELP component containing 4 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is lysine, valine, and phenylalanine at a relative ratio of 1:2:1; ELP1 [K1V7F1-9] designates a polypeptide containing 9 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is lysine, valine, and phenylalanine at a relative ratio of 1:7:1; ELP1 [V-5] designates a polypeptide containing 5 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is exclusively valine; ELP1 [V-20] designates a polypeptide containing 20 repeating units of the pentapeptide VPGXG (SEQ ID NO:3), where X is exclusively valine; ELP2 [5] designates a polypeptide containing 5 repeating units of the pentapeptide AVGVP (SEQ ID NO:4); ELP3 [V-5] designates a polypeptide containing 5 repeating units of the pentapeptide IPGXG (SEQ ID NO:5), where X is exclusively valine; ELP4 [V-5] designates a polypeptide containing 5 repeating units of the pentapeptide LPGXG (SEQ ID NO:7), where X is exclusively valine. Such ELP components as described in this paragraph may be used in connection with the present invention to increase the therapeutic properties of the therapeutic component.
Further, the Tt is a function of the hydrophobicity of the guest residue. Thus, by varying the identity of the guest residue(s) and their mole fraction(s), ELPs can be synthesized that exhibit an inverse transition over a 0-100° C. range. Thus, the Tt at a given ELP length may be decreased by incorporating a larger fraction of hydrophobic guest residues in the ELP sequence. Examples of suitable hydrophobic guest residues include valine, leucine, isoleucine, phenyalanine, tryptophan and methionine. Tyrosine, which is moderately hydrophobic, may also be used. Conversely, the Tt may be increased by incorporating residues, such as those selected from the group consisting of: glutamic acid, cysteine, lysine, aspartate, alanine, asparagine, serine, threonine, glycine, arginine, and glutamine; preferably selected from alanine, serine, threonine and glutamic acid.
The ELP component in some embodiments is selected or designed to provide a Tt ranging from about 10 to about 80° C., such as from about 35 to about 60° C., or from about 38 to about 45° C. In some embodiments, the Tt is greater than about 40° C. or greater than about 42° C., or greater than about 45° C., or greater than about 50° C. The transition temperature, in some embodiments, is above the body temperature of the subject or patient (e.g., >37° C.) thereby remaining soluble in vivo, or in other embodiments, the Tt is below the body temperature (e.g., <37° C.) to provide alternative advantages, such as in vivo formation of a drug depot for sustained release of the therapeutic agent.
The Tt of the ELP component can be modified by varying ELP chain length, as the Tt generally increases with decreasing MW. For polypeptides having a molecular weight>100,000, the hydrophobicity scale developed by Urry et al. (PCT/US96/05186, which is hereby incorporated by reference in its entirety) is preferred for predicting the approximate Tt of a specific ELP sequence. However, in some embodiments, ELP component length can be kept relatively small, while maintaining a target Tt, by incorporating a larger fraction of hydrophobic guest residues (e.g., amino acid residues having hydrophobic side chains) in the ELP sequence. For polypeptides having a molecular weight<100,000, the Tt may be predicted or determined by the following quadratic function: Tt=M0+M1X+M2X2 where X is the MW of the fusion protein, and M0=116.21; M1=−1.7499; M2=0.010349.
While the Tt of the ELP component, and therefore of the ELP component coupled to a therapeutic component, is affected by the identity and hydrophobicity of the guest residue, X, additional properties of the molecule may also be affected. Such properties include, but are not limited to solubility, bioavailability, persistence, and half-life of the molecule.
As described in PCT/US2007/077767 (published as WO 2008/030968), which is hereby incorporated by reference in its entirety, the ELP-coupled therapeutic component can retain the therapeutic component's biological activity. Additionally, ELPs themselves can exhibit long half-lives. Therefore, ELP components in accordance with the present invention substantially increase (e.g. by greater than 10%, 20%, 30%, 50%, 100%, 200%, 500% or more, in specific embodiments) the half-life of the therapeutic component when conjugated thereto. Such half-life (or in some embodiments persistance or rate of clearance) is determined in comparison to the half-life of the free (unconjugated or unfused) form of the therapeutic component. Furthermore, ELPs may target high blood content organs, when administered in vivo, and thus, can partition in the body, to provide a predetermined desired corporeal distribution among various organs or regions of the body, or a desired selectivity or targeting of a therapeutic agent. In sum, the therapeutic agents contemplated by the invention are administered or generated in vivo as active compositions having extended half-lives (e.g., circulatory half-life), among other potential benefits described herein.
The invention thus provides various agents for therapeutic (in vivo) application, where the therapeutic component is biologically active. Such therapeutic components include, without limitation, growth hormone (GH) particularly human and bovine growth hormone, growth hormone-releasing hormones; interferon including α-. β-, or γ-interferons, etc, interleukin-I; interleukin-II; erythropoietin including α- and β-erythropoietin (EPO), granulocyte colony stimulating factor (GCSF), granulocyte macrophage colony stimulating factor (GM-CSF), anti-agiogenic proteins (e.g., angiostatin, endostatin) PACAP polypeptide (pituitary adenylate cyclase activating polypeptide), vasoactive intestinal peptide (VIP), thyrotrophin releasing hormone (TRH), corticotropin releasing hormone (CRH), vasopressin, arginine vasopressin (AVP), angiotensin, calcitonin, atrial naturetic factor, somatostatin, adrenocorticotropin, gonadotropin releasing hormone, oxytocin, insulin, somatotropin, plasminogen tissue activator, coagulation factors including coagulation factors VIII and IX, glucosylceramidase, sargramostim, lenograstin, filgrastin, dornase-α, molgramostim, PEG-L-asparaginase, PEG-adenosine deaminase, hirudin, eptacog-α (human blood coagulation factor VIIa) nerve growth factors, transforming growth factor, epidermal growth factor, basic fibroblast growth factor, VEGF; heparin including low molecular weight heparin, calcitonin; antigens; monoclonal antibodies; vancomycin; desferrioxamine (DFO); parathyroid hormone, an immunogen or antigen, an antibody such as a monoclonal antibody.
Where the therapeutic component is an antibody or antibody sequence, the antibody may be of any isotype, including IgG, IgM, IgA, IgD, and IgE. Where the antibody is IgG, the subtype may be IgGi, IgG2, IgG3, or IgG4. The antibody sequence may be humanized or chimeric. The term “antibody” as used herein includes antibody fragments or segments that retain the capability of binding to a target antigen, for example, Fab, F(ab′)2, and Fv fragments, and the corresponding fragments obtained from antibodies other than IgG. Examples of therapeutic antibodies include but are not limited to herceptin, rituxan, campath, gemtuzumab, herceptin, panorex, rituximab, bexxar, edrecolomab, alemtuzumab, mylotrag, IMC-C225, smartin 195, and mitomomab.
The therapeutic component may also be a therapeutic component listed in Table 1 (e.g., full length or functional portions or functional analogs thereof), as well as GLP-1 receptor agonists such as GLP-1 or exendin-4, insulin, or Factor VII/VIIa, and functional analogs thereof. The structure and activity of such therapeutic components are described in detail below. In some forms of the therapeutic agent, the coupling of the therapeutic component to the elastic peptide is effected by direct covalent bonding or indirect (through appropriate spacer groups) bonding (as described elsewhere herein). Further, the therapeutic component(s) and the elastic peptide component(s) can be structurally arranged in any suitable manner involving such direct or indirect covalent bonding, relative to one another.
Glucagon-Like Peptide (GLP)-1 Receptor Agonists
In certain embodiments of the invention, the therapeutic agent comprises an ELP component fused or conjugated to a GLP-1 receptor agonist, such as GLP-1, exendin-4, or functional analogs thereof.
Human GLP-1 is a 37 amino acid residue peptide originating from preproglucagon which is synthesized in the L-cells in the distal ileum, in the pancreas, and in the brain. Processing of preproglucagon to give GLP-1(7-36)amide, GLP-1(7-37) and GLP-2 occurs mainly in the L-cells. A simple system is used to describe fragments and analogs of this peptide. For example, Gly8-GLP-1(7-37) designates a fragment of GLP-1 formally derived from GLP-1 by deleting the amino acid residues Nos. 1 to 6 and substituting the naturally occurring amino acid residue in position 8 (Ala) by Gly. Similarly, Lys34 (Nε-tetradecanoyl)-GLP-1(7-37) designates GLP-1(7-37) wherein the ε-amino group of the Lys residue in position 34 has been tetradecanoylated. Where reference in this text is made to C-terminally extended GLP-1 analogues, the amino acid residue in position 38 is Arg unless otherwise indicated, the optional amino acid residue in position 39 is also Arg unless otherwise indicated and the optional amino acid residue in position 40 is Asp unless otherwise indicated. Also, if a C-terminally extended analogue extends to position 41, 42, 43, 44 or 45, the amino acid sequence of this extension is as in the corresponding sequence in human preproglucagon unless otherwise indicated.
The parent peptide of GLP-1, proglucagon (PG), has several cleavage sites that produce various peptide products dependent on the tissue of origin including glucagon (PG[32-62]) and GLP-1[7-36]NH2 (PG[72-107]) in the pancreas, and GLP-1[7-37] (PG[78-108]) and GLP-1[7-36]NH2 (PG [78-107]) in the L cells of the intestine where GLP-1[7-36]NH2(78-107 PG) is the major product. The GLP-1 component in accordance with the invention may be any biologically active product or derivative of proglocagon, or functional analog thereof, including: GLP-1(1-35), GLP-1(1-36), GLP-1(1-36)amide, GLP-1(1-37), GLP-1(1-38), GLP-1(1-39), GLP-1(1-40), GLP-1(1-41), GLP-1(7-35), GLP-1(7-36), GLP-1(7-36)amide, GLP-1(7-37), GLP-1(7-38), GLP-1(7-39), GLP-1(7-40) and GLP-1(7-41), or a analog of the foregoing. Generally, the GLP-1 component in some embodiments may be expressed as GLP-1 (A-B), where A is an integer from 1 to 7 and B is an integer from 38 to 45, optionally with one or more amino acid substitutions as defined below.
As an overview, after processing in the intestinal L-cells, GLP-1 is released into the circulation, most notably in response to a meal. The plasma concentration of GLP-1 rises from a fasting level of approximately 15 pmol/L to a peak postprandial level of 40 pmol/L. For a given rise in plasma glucose concentration, the increase in plasma insulin is approximately threefold greater when glucose is administered orally compared with intravenously (Kreymann et al., 1987, Lancet 2(8571): 1300-4). This alimentary enhancement of insulin release, known as the incretin effect, is primarily humoral and GLP-1 is now thought to be the most potent physiological incretin in humans. GLP-1 mediates insulin production via binding to the GLP-1 receptor, known to be expressed in pancreatic β cells. In addition to the insulinotropic effect, GLP-1 suppresses glucagon secretion, delays gastric emptying (Wettergen et al., 1993, Dig Dis Sci 38: 665-73) and may enhance peripheral glucose disposal (D'Alessio et al., 1994, J. Clin Invest 93: 2293-6).
A combination of actions gives GLP-1 unique therapeutic advantages over other agents currently used to treat non-insulin-dependent diabetes mellitus (NIDDM). First, a single subcutaneous dose of GLP-1 can completely normalize post prandial glucose levels in patients with NIDDM (Gutniak et al., 1994, Diabetes Care 17: 1039-44). This effect may be mediated both by increased insulin release and by a reduction in glucagon secretion. Second, intravenous infusion of GLP-1 can delay postprandial gastric emptying in patients with NIDDM (Williams et al., 1996, J. Clin Endo Metab 81: 327-32). Third, unlike sulphonylureas, the insulinotropic action of GLP-1 is dependent on plasma glucose concentration (Holz et al., 1993, Nature 361:362-5). Thus, the loss of GLP-1-mediated insulin release at low plasma glucose concentration protects against severe hypoglycemia.
When given to healthy subjects, GLP-1 potently influences glycemic levels as well as insulin and glucagon concentrations (Orskov, 1992, Diabetologia 35:701-11), effects which are glucose dependent (Weir et al., 1989, Diabetes 38: 338-342). Moreover, it is also effective in patients with diabetes (Gutniak, M., 1992, N. Engl J Med 226: 1316-22), normalizing blood glucose levels in type 2 diabetic subjects and improving glycemic control in type 1 patients (Nauck et al., 1993, Diabetologia 36: 741-4, Creutzfeldt et al., 1996, Diabetes Care 19:580-6).
GLP-1 is, however, metabolically unstable, having a plasma half-life (t1/2) of only 1-2 minutes in vivo. Moreover, exogenously administered GLP-1 is also rapidly degraded (Deacon et al., 1995, Diabetes 44: 1126-31). This metabolic instability has limited the therapeutic potential of native GLP-1.
GLP-1[7-36]NH2 has the following amino acid sequence: HAEGTFTSDVSSYLEGQAAKEFIAWLVKGR (SEQ ID NO: 13), which may be employed as the GLP-1 component in accordance with the invention. Alternatively, the GLP-1 component may contain glycine (G) at the second position, giving, for example, the sequence HGEGTFTSDVSSYLEGQAAKEFIAWLVKGR (SEQ ID NO: 17). The GLP-1 component may be a biologically active fragment of GLP-1, for example, as disclosed in US 2007/0041951, which is hereby incorporated by reference in its entirety. Other fragments and modified sequences of GLP-1 are known in the art (U.S. Pat. No. 5,614,492; U.S. Pat. No. 5,545,618; European Patent Application, Publication No. EP 0658568 A1; WO 93/25579, which are hereby incorporated by reference in their entireties). Such fragments and modified sequences may be used in connection with the present invention, as well as those described below.
Certain structural and functional analogs of GLP-1 have been isolated from the venom of the Gila monster lizards (Heloderma suspectum and Heloderma horridum) and have shown clinical utility. Such molecules find use in accordance with the present invention. In particular, exendin-4 is a 39 amino acid residue peptide isolated from the venom of Heloderma suspectum and shares approximately 52% homology with human GLP-1. Exendin-4 is a potent GLP-1 receptor agonist that stimulates insulin release, thereby lowering blood glucose levels. Exendin-4 has the following amino acid sequence: HGEGTFTSDLSKQMEEEAVRLFEWLKNGGPSSGAPPPS (SEQ ID NO: 14). A synthetic version of exendin-4 known as exenatide (marketed as Byetta®) has been approved for the treatment of Type-2 Diabetes. Although exenatide is structurally analogous to native GLP-1, it has a longer half-life after injection.
While exenatide has the ability to lower blood glucose levels on its own, it can also be combined with other medications such as metformin, a thiozolidinedione, a sulfonylureas, and/or insulin to improve glucose control. Exenatide is administered by injection subcutaneously twice per day using a pre-filled pen device. Typical human responses to exenatide include improvements in the initial rapid release of endogenous insulin, an increase in β-cell growth and replication, suppression of pancreatic glucagon release, delayed gastric emptying, and reduced appetite—all of which function to lower blood glucose. Unlike sulfonylureas and meglitinides, exenatide increases insulin synthesis and secretion in the presence of glucose only, thus lessening the risk of hypoglycemia. Despite the therapeutic utility of exenatide, it has certain undesirable traits, including the requirement of twice daily injections, gastrointestional side effects, and similar to native GLP-1, a relatively short half-life (i.e. approximately 2 hr).
Various functional analogs of GLP-1 and exendin-4 are known, and which find use in accordance with the invention. These include liraglutide (Novo Nordisk, WO98/008871), R1583/taspoglutide (Roche, WO00/034331), CJC-1131 (ConjuChem, WO00/069911), ZP-10/AVE0010 (Zealand Pharma, Sanofi-Aventis, WO01/004156), and LY548806 (Eli Lilly, WO03/018516).
Liraglutide, also known as NN2211, is a GLP-1 receptor agonist analog that has been designed for once-daily injection (Harder et al., 2004, Diabetes Care 27: 1915-21). Liraglutide has been tested in patients with type-2 diabetes in a number of studies and has been shown to be effective over a variety of durations. In one study, treatment with liraglutide improved glycemic control, improved β-cell function, and reduced endogenous glucose release in patients with type-2 diabetes after one week of treatment (Degn et al., 2004, Diabetes 53: 1187-94). In a similar study, eight weeks of 0.6-mg liraglutide therapy significantly improved glycemic control without increasing weight in subjects with type 2 diabetes compared with those on placebo (Harder et al., 2004, Diabetes Care 27: 1915-21).
Thus, in certain embodiments, the GLP-1 receptor agonist in accordance with the invention is as described in WO98/008871, which is hereby incorporated by reference in its entirety. The GLP-1 receptor agonist may have at least one lipophilic substituent, in addition to one, two, or more amino acid substitutions with respect to native GLP-1. For example, the lipophilic substituent may be an acyl group selected from CH3(CH2)nCO—, wherein n is an integer from 4 to 38, such as an integer from 4 to 24. The lipophilic substituent may be an acyl group of a straight-chain or branched alkyl or fatty acid (for example, as described in WO98/008871, which description is hereby incorporated by reference).
In certain embodiments, the GLP-1 component is Arg26-GLP-1(7-37), Arg34-GLP-1(7-37), Lys36-GLP-1(7-37), Arg26,34Lys36-GLP-I (7-37), Arg26,34Lys38-GLP-I (7-38), Arg28,34 Lys39-GLP-1(7-39), Arg26,34Lys40-GLP-1(7-40), Arg26Lys36-GLP-1(7-37), Arg34Lys36-GLP-1(7-37), Arg26Lys39-GLP-1(7-39), Arg34Lys40-GLP-1(7-40), Arg26,34Lys36,39-GLP-I (7-39), Arg26,34Lys36,40-GLP-1(7-40), Gly8Arg26-GLP-1(7-37); Gly8Arg34-GLP-1(7-37); Gly8Lys38-GLP-1(7-37); Gly8Arg26,34Lys36-GLP-1(7-37), Gly8Arg26,34Lys39-GLP-1(7-39), Gly8Arg26,34Lys40-GLP-1(7-40), Gly8Arg26Lys36-GLP-1(7-37), Gly8Arg34Lys36-GLP-1(7-37), Gly8Arg26Lys39- GLP-1(7-39); Gly8Arg34Lys40-GLP-1(7-40), Gly8Arg28,34Lys36,39-GLP-1(7-39) and Gly8Arg26,34Lys35,40-GLP-1(7-40), each optionally having a lipophilic substituent. For example, the GLP-1 receptor agonist may have the sequence/structure Arg34Lys26-(N-ε-(γ-Glu(N-α-hexadecanoyl)))-GLP-I(7-37).
Taspoglutide, also known as R1583 or BIM 51077, is a GLP-1 receptor agonist that has been shown to improve glycemic control and lower body weight in subjects with type 2 diabetes mellitus treated with metformin (Abstract No. A-1604, Jun. 7, 2008, 68th American Diabetes Association Meeting, San Francisco, Calif.).
Thus, in certain embodiments, the GLP-1 receptor agonist is as described in WO00/034331, which is hereby incorporated by reference in its entirety. In certain exemplary embodiments, the GLP-1 receptor agonist has the sequence [Aib8,35]hGLP-1(7-36)NH2 (e.g. taspoglutide), wherein Aib is alpha-aminoisobutyric acid.
CJC-1131 is a GLP-1 analog that consists of a DPP-IV-resistant form of GLP-1 joined to a reactive chemical linker group that allows GLP-1 to form a covalent and irreversible bond with serum albumin following subcutaneous injection (Kim et al., 2003, Diabetes 52: 751-9). In a 12-week, randomized, double-blind, placebo-controlled multicenter study, CJC-1131 and metformin treatment was effective in reducing fasting blood glucose levels in type 2 diabetes patients (Ratner et al., Abstract No. 10-OR, Jun. 10-14, 2005, 65th American Diabetes Association Meeting, San Francisco, Calif.).
Thus, in certain embodiments, the GLP-1 receptor agonist is as described in WO00/069911, which is hereby incorporated by reference in its entirety. In some embodiments, the GLP-1 receptor agonist is modified with a reactive group which reacts with amino groups, hydroxyl groups or thiol groups on blood components to form a stable covalent bond. In certain embodiments, the GLP-1 receptor agonist is modified with a reactive group selected from the group consisting of succinimidyl and maleimido groups. In certain exemplary embodiments, the GLP-1 receptor agonist has the sequence/structure: D-Ala8Lys37-(2-(2-(2-maleimidopropionamido(ethoxy)ethoxy)acetamide))-GLP-1(7-37) (e.g. CJC-1131).
AVE0010, also known as ZP-10, is a GLP-1 receptor agonist that may be employed in connection with the invention. In a recent double-blind study, patients treated with once daily dosing of AVE0010 demonstrated significant reductions in HbA1c levels (Ratner et al., Abstract No. 433-P, 68th American Diabetes Association Meeting, San Francisco, Calif.). At the conclusion of the study, the percentages of patients with HbA1c <7% ranged from 47-69% for once daily dosing compared to 32% for placebo. In addition, AVE0010 treated patients showed dose-dependent reductions in weight and post-prandial plasma glucose.
Thus, in certain embodiments, the GLP-1 receptor agonist is as described in WO01/004156, which is hereby incorporated by reference in its entirety. For example, the GLP-1 receptor agonist may have the sequence: HGEGTFTSDLSKQMEEEAVRLFIEWLKNGGPSSGAPPSKKKKKK-NH2 (SEQ ID NO: 18) (e.g. AVE0010).
LY548806 is a GLP-1 derivative designed to be resistant to proteolysis by dipeptidase-peptidyl IV (DPP-IV) (Jackson et al., Abstract No. 562, Jun. 10-14, 2005, 65th American Diabetes Association Meeting, San Francisco, Calif.). In an animal model of hyperglycemia, LY548806 has been shown to produce a significant lowering of blood glucose levels during the hyperglycemic phase (Saha et al., 2006, J. Pharm. Exp. Ther. 316: 1159-64). Moreover, LY548806 was shown to produce a significant increase in insulin levels consistent with its known mechanism of action, namely stimulation of insulin release in the presence of hyperglycemia.
Thus, in certain embodiments, the GLP-1 receptor agonist is as described in WO03/018516, which is hereby incorporated by reference in its entirety. In some embodiments, the therapeutic agents of the present invention comprise GLP-1 analogs wherein the backbone for such analogs or fragments contains an amino acid other than alanine at position 8 (position 8 analogs). The backbone may also include L-histidine, D-histidine, or modified forms of histidine such as desamino-histidine, 2-amino-histidine, β-hydroxy-histidine, homohistidine, α-fluoromethyl-histidine, or α-methyl-histidine at position 7. In some embodiments, these position 8 analogs may contain one or more additional changes at positions 12, 16, 18, 19, 20, 22, 25, 27, 30, 33, and 37 compared to the corresponding amino acid of native GLP-1. In other embodiments, these position 8 analogs may contain one or more additional changes at positions 16, 18, 22, 25 and 33 compared to the corresponding amino acid of native GLP-1. In certain exemplary embodiments, the GLP-1 receptor agonist has the sequence: HVEGTFTSDVSSYLEEQAAKEFIAWLIKGRG-OH (SEQ ID NO: 19) (e.g. LY548806).
Thus, the present invention provides therapeutic agents comprising an elastic peptide (e.g., an ELP) and a GLP-1 receptor agonist. For example, in certain embodiments, the GLP-1 receptor agonist is GLP-1 (SEQ ID NO:13, 17, or 59) or a functional analog thereof. In other embodiments, the GLP-1 receptor agonist is exendin-4 (SEQ ID NO:14) or a functional analog thereof. Such functional analogs of GLP-1 or exendin-4 include functional fragments truncated at the C-terminus by from 1 to 10 amino acids, including by 1, 2, 3, or up to about 5 amino acids (with respect to SEQ ID NOS: 13, 14, 17, or 59). Such functional analogs may contain from 1 to 10 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the native sequence (e.g., SEQ ID NOS 13, 14, and 59), and in each case retaining the activity of the peptide. For example, the functional analog of GLP-1 or exendin-4 may have from 1 to about 3, 4, or 5 insertions, deletions and/or substitutions (collectively) with respect to SEQ ID NOS: 13, 59 and 14, and in each case retaining the activity of the peptide. Such activity may be confirmed or assayed using any available assay, including those described herein. In these or other embodiments, the GLP-1 receptor agonist component has at least about 50%, 75%, 80%, 85%, 90%, or 95% identity with the native sequence (SEQ ID NOS: 13, 59, and 14). The determination of sequence identity between two sequences (e.g., between a native sequence and a functional analog) can be accomplished using any alignment tool, including Tatusova et al., Blast 2 sequences—a new tool for comparing protein and nucleotide sequences, FEMS Microbiol Lett. 174:247-250(1999). Such functional analogs may further comprise additional chemical modifications, such as those described in this section and/or others known in the art.
In certain embodiments, the GLP1-ELP fusion has a sequence exemplified herein as SEQ ID NOS: 54 and 56. When processed, the mature form of such fusion protein will begin with the His7 of GLP.
In another aspect, the present invention provides methods for the treatment or prevention of type 2 diabetes, impaired glucose tolerance, type 1 diabetes, hyperglycemia, obesity, binge eating, bulimia, hypertension, syndrome X, dyslipidemia, cognitive disorders, atheroschlerosis, non-fatty liver disease, myocardial infarction, coronary heart disease and other cardiovascular disorders. The method comprises administering the therapeutic agent comprising the elastin-like peptide (ELP) and the GLP-1 receptor agonist (as described above) to a patient in need of such treatment. In these or other embodiments, the present invention provides methods for decreasing food intake, decreasing β-cell apoptosis, increasing β-cell function and β-cell mass, and/or for restoring glucose sensitivity to β-cells. Generally, the patient may be a human or non-human animal patient (e.g., dog, cat, cow, or horse). Preferably, the patient is human.
The treatment with a ELP/GLP-1 receptor agonist compound according to the present invention may also be combined with one or more pharmacologically active substances, e.g. selected from antidiabetic agents, antiobesity agents, appetite regulating agents, antihypertensive agents, agents for the treatment and/or prevention of complications resulting from or associated with diabetes and agents for the treatment and/or prevention of complications and disorders resulting from or associated with obesity. In the present context, the expression “antidiabetic agent” includes compounds for the treatment and/or prophylaxis of insulin resistance and diseases wherein insulin resistance is the pathophysiological mechanism.
The ability of a GLP-1 or exendin-4 analog, or an GLP-1 receptor agonist/elastic peptide compound, to bind the GLP-1 receptor may be determined by standard methods, for example, by receptor-binding activity screening procedures which involve providing appropriate cells that express the GLP-1 receptor on their surface, for example, insulinoma cell lines such as RINmSF cells or INS-1 cells. In addition to measuring specific binding of tracer to membrane using radioimmunoassay methods, cAMP activity or glucose dependent insulin production can also be measured. In one method, a polynucleotide encoding the GLP-1 receptor is employed to transfect cells to thereby express the GLP-1 receptor protein. Thus, these methods may be employed for testing or confirming whether a suspected GLP-1 receptor agonist is active. An exemplary assay is described in greater detail herein.
In addition, known methods can be used to measure or predict the level of biologically activity of a GLP-1 receptor agonist or GLP-1 receptor agonist/elastic peptide in vivo (See e.g. Siegel, et al., 1999, Regul Pept 79(2-3): 93-102). In particular, GLP-1 receptor agonists or GLP-1 receptor agonist/elastic peptide compounds can be assessed for their ability to induce the production of insulin in vivo using a variety of known assays for measuring GLP-1 activity. For example, a GLP-1 receptor agonist/elastic peptide compound can be introduced into a cell, such as an immortalized β-cell, and the resulting cell can be contacted with glucose. If the cell produces insulin in response to the glucose, then the modified GLP-1 is generally considered biologically active in vivo (Fehmann et al., 1992, Endocrinology 130: 159-166). An exemplary assay is described in greater detail herein.
The ability of an GLP-1 receptor agonist/elastic peptide compound to enhance β-cell proliferation, inhibit β-cell apoptosis, and regulate islet growth may also be measured using known assays. Pancreatic β-cell proliferation may be assessed by 3H-tymidine or BrdU incorporation assays (See e.g. Buteau et al., 2003, Diabetes 52: 124-32), wherein pancreatic β-cells such as INS(832/13) cells are contacted with a GLP-1 receptor agonist/elastic peptide compound and analyzed for increases in 3H-thymidine or BrdU incorporation. The antiapoptotic activity of a GLP-1 receptor agonist/elastic peptide compound can be measured in cultured insulin-secreting cells and/or in animal models where diabetes occurs as a consequence of an excessive rate of beta-cell apoptosis (See e.g. Bulotta et al., 2004, Cell Biochem Biophys 40(3 suppl): 65-78).
In addition to GLP-1, other peptides of this family, such as those derived from processing of the pro-glucagon gene, such as GLP-2, GIP, and oxyntomodulin, could be conjugated or fused to the elastic peptide component (as described herein) to enhance the therapeutic potential.
Insulin
In other embodiments, the present invention provides a therapeutic agent comprising an elastin peptide component coupled to insulin (e.g., via fusion or conjugation). Insulin injections, e.g. of human insulin, can be used to treat diabetes. The insulin-making cells of the body are called β-cells, and they are found in the pancreas gland. These cells clump together to form the “islets of Langerhans”, named for the German medical student who described them.
The synthesis of insulin begins at the translation of the insulin gene, which resides on chromosome 11. During translation, two introns are spliced out of the mRNA product, which encodes a protein of 110 amino acids in length. This primary translation product is called preproinsulin and is inactive. It contains a signal peptide of 24 amino acids in length, which is required for the protein to cross the cell membrane.
Once the preproinsulin reaches the endoplasmic reticulum, a protease cleaves off the signal peptide to create proinsulin. Proinsulin consists of three domains: an amino-terminal B chain, a carboxyl-terminal A chain, and a connecting peptide in the middle known as the C-peptide. Insulin is composed of two chains of amino acids named chain A (21 amino acids—GIVEQCCASVCSLYQLENYCN) (SEQ ID NO: 15) and chain B (30 amino acids FVNQHLCGSHLVEALYLVCGERGFFYTPKA) (SEQ ID NO: 16) that are linked together by two disulfide bridges. There is a 3rd disulfide bridge within the A chain that links the 6th and 11th residues of the A chain together. In most species, the length and amino acid compositions of chains A and B are similar, and the positions of the three disulfide bonds are highly conserved. For this reason, pig insulin can replace deficient human insulin levels in diabetes patients. Today, porcine insulin has largely been replaced by the mass production of human proinsulin by bacteria (recombinant insulin).
Insulin molecules have a tendency to form dimers in solution, and in the presence of zinc ions, insulin dimers associate into hexamers. Whereas monomers of insulin readily diffuse through the blood and have a rapid effect, hexamers diffuse slowly and have a delayed onset of action. In the design of recombinant insulin, the structure of insulin can be modified in a way that reduces the tendency of the insulin molecule to form dimers and hexamers but that does not interrupt binding to the insulin receptor. In this way, a range of preparations are made, varying from short acting to long acting.
Within the endoplasmic reticulum, proinsulin is exposed to several specific peptidases that remove the C-peptide and generate the mature and active form of insulin. In the Golgi apparatus, insulin and free C-peptide are packaged into secretory granules, which accumulate in the cytoplasm of the β-cells. Exocytosis of the granules is triggered by the entry of glucose into the beta cells. The secretion of insulin has a broad impact on metabolism.
There are two phases of insulin release in response to a rise in glucose. The first is an immediate release of insulin. This is attributable to the release of preformed insulin, which is stored in secretory granules. After a short delay, there is a second, more prolonged release of newly synthesized insulin.
Once released, insulin is active for a only a brief time before it is degraded by enzymes. Insulinase found in the liver and kidneys breaks down insulin circulating in the plasma, and as a result, insulin has a half-life of only about 6 minutes. This short duration of action results in rapid changes in the circulating levels of insulin.
Insulin analogs have been developed with improved therapeutic properties (Owens et al., 2001, Lancet 358: 739-46; Vajo et al., 2001, Endocr Rev 22: 706-17), and such analogs may be employed in connection with the present invention. Various strategies, including elongation of the COOH-terminal end of the insulin B-chain and engineering of fatty acid-acylated insulins with substantial affinity for albumin are used to generate longer-acting insulin analogs. However, in vivo treatments with available longer-acting insulin compounds still result in a high frequency of hypo- and hyperglycemic excursions and modest reduction in HbA1c. Accordingly, development of a truly long-acting and stable human insulin analog still remains an important task.
Functional analogs of insulin that may be employed in accordance with the invention include rapid acting analogs such as lispro, aspart and glulisine, which are absorbed rapidly (<30 minutes) after subcutaneous injection, peak at one hour, and have a relatively short duration of action (3 to 4 hours). In addition, two long acting insulin analogs have been developed: glargine and detemir, and which may be employed in connection with the invention. The long acting insulin analogs have an onset of action of approximately two hours and reach a plateau of biological action at 4 to 6 hours, and may last up to 24 hours.
Thus, in one embodiment, the insulin component may contain the A and/or B chain of lispro (also known as Humalog, Eli Lilly). Insulin lispro differs from human insulin by the substitution of proline with lysine at position 28 and the substitution of lysine with proline at position 29 of the insulin B chain. Although these modifications do not alter receptor binding, they help to block the formation of insulin dimers and hexamers, allowing for larger amounts of active monomeric insulin to be available for postprandial injections.
In another embodiment, the insulin may contain an A and/or B chain of aspart (also known as Novolog, Novo Nordisk). Insulin aspart is designed with the single replacement of the amino acid proline by aspartic acid at position 28 of the human insulin B chain. This modification helps block the formation for insulin hexamers, creating a faster acting insulin.
In yet another embodiment, the insulin may contain an A and/or B chain of glulisine (also known as Apidra, Sanofi-Aventis). Insulin glulisine is a short acting analog created by substitution of asparagine at position 3 by lysine and lysine at position 29 by glutamine of human insulin B chain. Insulin glulisine has more rapid onset of action and shorter duration of action compared to regular human insulin.
In another embodiment, the insulin may contain an A and/or B chain of glargine (also known as Lantus, Sanofi-Aventis). Insulin glargine differs from human insulin in that the amino acid asparagine at position 21 of the A chain is replaced by glycine and two arginines are added to the C-terminus of the B-chain. Compared with bedtime neutral protamine Hagedorn (NPH) insulin (an intermediate acting insulin), insulin glargine is associated with less nocturnal hypoglycemia in patients with type 2 diabetes.
In yet another embodiment, the insulin may contain an A and/or B chain from detemir (also known as Levemir, Novo Nordisk). Insulin detemir is a soluble (at neutral pH) long-acting insulin analog, in which the amino acid threonine at B30 is removed and a 14-carbon, myristoyl fatty acid is acetylated to the epsilon-amino group of LysB29. After subcutaneous injection, detemir dissociates, thereby exposing the free fatty acid which enables reversible binding to albumin molecules. So at steady state, the concentration of free unbound insulin is greatly reduced resulting in stable plasma glucose levels.
In some embodiments, the insulin may be a single-chain insulin analog (SIA) (e.g. as described in U.S. Pat. No. 6,630,438 and WO08/019368, which are hereby incorporated by reference in their entirety). Single-chain insulin analogs encompass a group of structurally-related proteins wherein the A and B chains are covalently linked by a polypeptide linker. The polypeptide linker connects the C-terminus of the B chain to the N-terminus of the A chain. The linker may be of any length so long as the linker provides the structural conformation necessary for the SIA to have a glucose uptake and insulin receptor binding effect. In some embodiments, the linker is about 5-18 amino acids in length. In other embodiments, the linker is about 9-15 amino acids in length. In certain embodiments, the linker is about 12 amino acids long. In certain exemplary embodiments, the linker has the sequence KDDNPNLPRLVR (SEQ ID NO.: 20) or GAGSSSRRAPQT (SEQ ID NO.: 21). However, it should be understood that many variations of this sequence are possible such as in the length (both addition and deletion) and substitutions of amino acids without substantially compromising the effectiveness of the produced SIA in glucose uptake and insulin receptor binding activities. For example, several different amino acid residues may be added or removed from either end without substantially decreasing the activity of the produced SIA.
An exemplary single-chain insulin analog currently in clinical development is albulin (Duttaroy et al., 2005, Diabetes 54: 251-8). Albulin can be produced in yeast or in mammalian cells. It consists of the B and A chain of human insulin (100% identity to native human insulin) linked together by a dodecapeptide linker and fused to the NH2 terminals of the native human serum albumin. For expression and purification of albulin, Duttaroy et al. constructed a synthetic gene construct encoding a single-chain insulin containing the B- and A-chain of mature human insulin linked together by a dodecapeptide linker using four overlapping primers and PCR amplification. The resulting PCR product was ligated in-frame between the signal peptide of human serum albumin (HSA) and the NH2 terminus of mature HSA, contained within a pSAC35 vector for expression in yeast. In accordance with the present invention, the HSA component of abulin may be replaced with an ELP component as described herein.
Thus, in one aspect, the present invention provides therapeutic agents comprising an elastic peptide and an insulin or functional analog thereof. For example, in certain embodiments, the insulin is a mammalian insulin, such as human insulin or porcine insulin. In accordance with the invention, the elastic peptide component may be coupled (e.g., via recombinant fusion or chemical conjugation) to the insulin A chain, or B chain, or both. The insulin may comprise each of chains A, B, and C (SEQ ID NOS: 51 and 52), or may contain a processed form, containing only chains A and B. In some embodiments, chains A and B are connected by a short linking peptide, to create a single chain insulin. The insulin may be a functional analog of human insulin, including functional fragments truncated at the N-terminus and/or C-terminus (of either or both of chains A and B) by from 1 to 10 amino acids, including by 1, 2, 3, or about 5 amino acids. Functional analogs may contain from 1 to 10 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the native sequence (e.g., SEQ ID NOS 15 and 16), and in each case retaining the activity of the peptide. For example, functional analogs may have 1, 2, 3, 4, or 5 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the native sequence (which may contain chains A and B, or chains A, B, and C). Such activity may be confirmed or assayed using any available assay, including those described herein. In these or other embodiments, the insulin component has at least about 75%, 80%, 85%, 90%, 95%, or 98% identity with each of the native sequences for chains A and B (SEQ ID NOS:15 and 16). The determination of sequence identity between two sequences (e.g., between a native sequence and a functional analog) can be accomplished using any alignment tool, including Tatusova et al., Blast 2 sequences—a new tool for comparing protein and nucleotide sequences FEMS Microbiol Lett. 174:247-250(1999). The insulin component may contain additional chemical modifications known in the art.
In another aspect, the present invention provides methods for the treatment or prevention of diabetes, including type I and II diabetes. The method comprises administering an effective amount of the therapeutic agent comprising an elastic peptide (e.g., ELP) component and an insulin (or functional analog thereof) component to a patient in need thereof. Generally, the patient may be a human or non-human animal (e.g., dog, cat, cow, or horse) patient. Preferably, the patient is human.
To characterize the in vitro binding properties of an insulin analog or an elastic peptide-containing insulin analog, competition binding assays may be performed in various cell lines that express the insulin receptor (Jehle et al., 1996, Diabetologia 39: 421-432). For example, competition binding assays using CHO cells overexpressing the human insulin receptor may be employed. Insulin can also bind to the IGF-1 receptor with a lower affinity than the insulin receptor. To determine the binding affinity of an ELP-containing insulin analog, a competition binding assay can be performed using 125I-labeled IGF-1 in L6 cells.
The activities of insulin include stimulation of peripheral glucose disposal and inhibition of hepatic glucose production. The ability of an elastic peptide-containing insulin analog to mediate these biological activities can be assayed in vitro using known methodologies. For example, the effect of an elastic peptide-containing analog on glucose uptake in 3T3-L1 adipocytes can be measured and compared with that of insulin. Pretreatment of the cells with a biologically active analog will generally produce a dose-dependent increase in 2-deoxyglucose uptake. The ability of an elastic peptide-containing insulin analog to regulate glucose production may be measured in any number of cells types, for example, H4Ile hepatoma cells. In this assay, pretreatment with a biologically active analog will generally result in a dose-dependent inhibition of the amount of glucose released.
Factor VII (VIIa)
In certain embodiments, the invention provides therapeutic agents comprising an elastic peptide component coupled (e.g., via fusion or conjugation) to a Factor VII/VIIa. Coagulation is the biological process of blood clot formation involving many different serine proteases as well as their essential cofactors and inhibitors. It is initiated by exposure of Factor VII (FVII) and Factor VIIa (FVIIa) to its membrane bound cofactor, tissue factor (TF), resulting in production of Factor Xa (FXa) and more FVIIa. The process is propagated upon production of Factor IXa (FIXa) and additional FXa that, upon binding with their respective cofactors FVIIIa and FVa, form platelet bound complexes, ultimately resulting in the formation of thrombin and a fibrin clot. Thrombin also serves to further amplify coagulation by activation of cofactors such as FV and FVII and zymogens such as Factor XI. Moreover, thrombin activates platelets leading to platelet aggregation, which is necessary for the formation of a hemostatic plug.
Factor VII circulates in the blood in a zymogen form, and is converted to its active form, Factor VIIa, by either factor IXa, factor Xa, factor XIIa, or thrombin by minor proteolysis. Factor VIIa is a two-chain, 50 kilodalton (kDa) plasma serine protease. The active form of the enzyme comprises a heavy chain (254 amino acid residues) containing a catalytic domain and a light chain (152 residues) containing 2 epidermal growth factor (EGF)-like domains. The mature factor VII/VIIa that circulates in plasma is composed of 406 amino acid residues (SEQ ID NO: 33). The light and heavy chains are held together by a disulfide bond.
As noted above, Factor VIIa is generated by proteolysis of a single peptide bond from its single chain zymogen, Factor VII, which is present at approximately 0.5 μg/ml in plasma. The conversion of zymogen Factor VII into the activated two-chain molecule occurs by cleavage of an internal peptide bond. In human Factor VII, the cleavage site is at Arg152-Ile153 (Hagen et al., 1986, PNAS USA 83: 2412-6).
“Factor VII/VIIa” as used in this application means a product consisting of either the unactivated form (factor VII) or the activated form (factor VIIa) or mixtures thereof. “Factor VII/VIIa” within the above definition includes proteins that have an amino acid sequence of native human factor VII/VIIa. It also includes proteins with a slightly modified amino acid sequence, for instance, a modified N-terminal end including N-terminal amino acid deletions or additions so long as those proteins substantially retain the activity of factor VIIa. “Factor VII” within the above definition also includes natural allelic variations that may exist and occur from one individual to another. Also, degree and location of glycosylation or other post-translation modifications may vary depending on the chosen host cells and the nature of the host cellular environment.
In the presence of calcium ions, Factor VIIa binds with high affinity to TF. TF is a 263 amino acid residue glycoprotein composed of a 219 residue extracellular domain, a single transmembrane domain, and a short cytoplasmic domain (Morrissey et al., 1987, Cell 50: 129-35). The TF extracellular domain is composed of two fibronectin type III domains of about 105 amino acids each. The binding of FVIIa is mediated entirely by the TF extracellular domain (Muller et al., 1994, Biochem. 33:10864-70). Residues in the area of amino acids 16-26 and 129-147 contribute to the binding of FVIIa as well as the coagulant function of the molecule. Residues Lys20, Trp45, Asp58, Tyr94, and Phe140 make a large contribution (1 kcal/mol) to the free energy (ΔG) of binding to FVIIa.
TF is expressed constitutively on cells separated from plasma by the vascular endothelium. Its expression on endothelial cells and monocytes is induced by exposure to inflammatory cytokines or bacterial lipopolysaccharides (Drake et al., 1989, J. Cell Biol. 109: 389). Upon tissue injury, the exposed extracellular domain of TF forms a high affinity, calcium dependent complex with FVII. Once bound to TF, FVII can be activated by peptide bond cleavage to yield serine protease FVIIa. The enzyme that catalyzes this step in vivo has not been elucidated, but in vitro FXa, thrombin, TF:FVIIa and FIXa can catalyze this cleavage. FVIIa has only weak activity upon its physiological substrates FX and FIX whereas the TF:FVIIa complex rapidly activates FX and FIX.
The TF:FVIIa complex constitutes the primary initiator of the extrinsic pathway of blood coagulation. The complex initiates the extrinsic pathway by activation of FX to Factor Xa (FXa), FIX to Factor IXa (FIXa), and additional FVII to FVIIa. The action of TF:FVIIa leads ultimately to the conversion of prothrombin to thrombin, which carries out many biological functions. Among the most important activities of thrombin is the conversion of fibrinogen to fibrin, which polymerizes to form a clot. The TF:FVIIa complex also participates as a secondary factor in extending the physiological effects of the contact activation system.
The initiation and subsequent regulation of coagulation is complex, since maintenance of hemostasis is crucial for survival. There is an exquisite balance between hemostasis (normal clot formation and dissolution) and thrombosis (pathogenic clot formation). Serious clinical conditions involving aberrations in coagulation include deep vein thrombosis, myocardial infarction, pulmonary embolism, stroke and disseminated intravascular coagulation (in sepsis). There are also many bleeding coagulopathies where there is insufficient clot formation. These include hemophilia A (FVIII deficiency) or hemophilia B (FIX deficiency), where procoagulant therapy is required. The challenge in this therapeutic area is to operate in the narrow window between too much and too little coagulation.
The use of exogenous FVIIa as a therapeutic agent has been shown to induce hemostasis in patients with hemophilia A and B (Hedner, 2001, Seminars Hematol. 38 (suppl. 12): 43-7; Hedner, 2004, Seminars Hematol. 41 (suppl. 1): 35-9). It also has been used to treat bleeding in patients with liver disease, anticoagulation-induced bleeding, surgery, thrombocytopenia, thrombasthenia, Bemard-Soulier syndrome, von Willebrand disease, and other bleeding disorders (See e.g. Roberts et al., 2004, Blood 104: 3858-64).
Commercial preparations of human recombinant FVIIa are sold as NovoSeven.™ NovoSeven™ is indicated for the treatment of bleeding episodes in hemophilia A or B patients and is the only recombinant FVIIa effective for bleeding episodes currently available. A circulating recombinant FVIIa half-life of 2.3 hours was reported in “Summary Basis for Approval for NovoSeven™” FDA reference number 96-0597. Moreover, the half-life of recombinant FVIIa is shorter in pediatric patients (˜1.3 hours), suggesting that higher doses of recombinaint FVIIa may be required in this population (Roberts et al., 2004, Blood 104: 3858-64). Accordingly, relatively high doses and frequent administration are necessary to reach and sustain the desired therapeutic or prophylactic effect. As a consequence, adequate dose regulation is difficult to obtain and the need of frequent intravenous administrations imposes restrictions on the patient's way of living.
A molecule with a longer circulation half-life would decrease the number of necessary administrations. Given the frequent injections associated with currently available FVIIa therapy and the potential for obtaining more optimal therapeutic FVIIa levels with concomitant enhanced therapeutic effect, there is a clear need for improved FVII or FVIIa-like molecules with a longer half-life in vivo.
Recombinant human coagulation factor VIIa (rFVIIa, NovoSeven; Novo Nordisk A/S, Copenhagen, Denmark) has proven to be efficacious for the treatment of bleeding episodes in hemophilia patients with inhibitors. A small fraction of patients may be refractory to rFVIIa treatment and could potentially benefit from genetically modified FVIIa molecules with increased potencies. To this end, FVIIa analogs with increased intrinsic activity have been investigated that exhibit superior hemostatic profiles in vitro (see e.g. WO02/077218 or WO05/074975, which are hereby incorporated by reference in their entirety, and Tranholm et al., 2003, Blood 102(10): 3615-20, which is also incorporated by reference). These analogs may also be used as more efficacious hemostatic agents in other indications where efficacy of rFVIIa has been observed, including in thrombocytopenia and trauma.
Thus, in some embodiments, the Factor VIIa analog that may be used in accordance with the invention is as described in WO02/077218 or WO05/074975. For example, the FVIIa analog may have a glutamine substituted for methionine at position 298 (i.e. M298Q-FVIIa). In certain exemplary embodiments, the FVIIa analog contains two additional mutations, valine at position 158 replaced by aspartic acid and glutamic acid at position 296 replaced by valine (i.e. V158D/E296V/M298Q-FVIIa). Additionally or alternatively, the Factor VIIa analog may have an alanine residue substitution for lysine at position 337 (i.e. V158D/E296V/M298Q/K337A-FVIIa). In still other embodiments, the Factor VIIa analog has a substitution or insertion selected from Q250C; P406C; and 407C, wherein a cysteine has also been introduced in the C-terminal sequence (see, e.g. U.S. Pat. No. 7,235,638, which is hereby incorporated by reference in its entirety). The Factor VIIa analog may further comprise a substitution or insertion at one or more of positions 247, 260, 393, 396, and/or 405.
In these or other embodiments, the Factor VIIa analog comprises a substitution relative to the sequence of native Factor VIIa selected from: (a) a substitution of Lys157 with an amino acid selected from the group consisting of Gly, Val, Ser, Thr, Asp, and Glu; (b) a substitution of Lys337 with ah amino acid selected from the group consisting of Ala, Gly, Val, Ser, Thr, Gin, Asp, and Glu; (c) a substitution of Asp334 with any amino acid other than Ala or Asn; and (d) a substitution of Ser336 with any amino acid other than Ala or Cys (see e.g. U.S. Pat. No. 7,176,288, which is hereby incorporated by reference in its entirety). Additionally or alternatively, the Factor VIIa analog comprises a substitution of the Leu at position 305 of Factor VII with an amino acid residue selected from the group consisting of Val, Ile, Met, Phe, Trp, Pro, Gly, Ser, Thr, Cys, Tyr, Asn, Glu, Lys, Arg, His, Asp and Gln (see e.g. U.S. Pat. No. 6,905,683, which is hereby incorporated by reference in its entirety).
Thus, in one aspect, the present invention provides therapeutic agents comprising an elastic peptide, e.g., an elastin-like peptide (ELP) and a Factor VII/VIIa, or functional analog thereof. For example, in certain embodiments, the Factor VII/VIIa is human Factor VII/VIIa (e.g., SEQ ID NO: 33). The Factor VII/VIIa may be a functional analog of human Factor VII/VIIa, including functional fragments truncated at the N-terminus and/or C-terminus by from 1 to 10 amino acids, including by 1, 2, 3, or about 5 amino acids. Functional analogs may contain from 1 to 10 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the native sequence (e.g., SEQ ID NO: 33), and in each case retaining the activity of the peptide. For example, such analogs may have from 1 to about 5 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the native full length sequence, or with respect to one or both of the heavy and light chains. Such activity may be confirmed or assayed using any available assay, including those described herein. In these or other embodiments, the Factor VII/VIIa component has at least about 75%, 80%, 85%, 90%, 95%, or 98% identity with the native sequence (SEQ ID NO:33). The determination of sequence identity between two sequences (e.g., between a native sequence and a functional analog) can be accomplished using any alignment tool, including Tatusova et al., Blast 2 sequences—a new tool for comparing protein and nucleotide sequences, FEMS Microbiol Lett. 174:247-250(1999).
In exemplary embodiments, the FactorVII-ELP fusion has the amino acid sequence of SEQ ID NO:58. SEQ ID NO:58 further comprises a TEV protease cleavage site between the FactorVII and ELP sequences, which may be beneficial for removing the ELP sequence post expression where desired. However, in accordance with the invention, the tev sequence may be entirely removed, or replaced with another linking sequence as disclosed herein.
In another aspect, the present invention provides methods for the treatment or prevention of bleeding-related disorders. The method comprises administering an effective amount of the therapeutic agent comprising an elastic peptide and a Factor VII/VIIa or functional analog thereof to a patient in need. In certain embodiments, the bleeding-related disorder is one or more of hemophilia (A or B), post-surgical bleeding, anticoagulation-induced bleeding, thrombocytopenia, Factor VII deficiency, Factor XI deficiency, bleeding in patients with liver disease, thrombasthenia, Bemard-Soulier syndrome, von Willebrand disease, and intracranial hemorrhage. Generally, the patient is a human or non-human animal (e.g., dog, cat, cow, or horse) patient. Preferably, the patient is human.
To characterize the in vitro binding properties of a suspected Factor VII/VIIa analog, or an elastic peptide-containing Factor VIIa analog, TF binding assays can be performed as described previously (See, e.g., Chaing et al., 1994, Blood 83(12): 3524-35). Briefly, recombinant human TF can be coated onto Immulon II plates in carbonate antigen buffer overnight at 4° C. BSA is also coated onto the plates for use as a control. Elastic peptide-containing Factor VIIa analogs may be added at various concentrations in TBS-T buffer. After several washes, monospecific polyclonal rabbit anti-human FVIIa sera is added and incubated for approximately an hour at room temperature. Next, goat anti-rabbit IgG conjugated to alkaline phosphatase is added, followed by the alkaline phosphatase substrate PNPP, which is used for detection. After subtraction of background, the absorbance at ˜405 nm is taken to be directly proportional to the degree of Factor VIIa binding to the immobilized TF. These values can then be compared to control plasma containing Factor VIIa.
The clotting ability of a Factor VII/VIIa analog or an elastic peptide-containing Factor VIIa analog can be measured in human FVII deficient plasma. In this assay, the elastic peptide-containing Factor VIIa analog diluted to varying concentrations directly into FVII deficient plasma. In a coagulometer, one part plasma±a FVIIa analog can be mixed with 2 parts Innovin™ (Dade, Miami, Fla.) prothrombin time reagent (recombinant human tissue factor with phospholipids and CaCl2). Clot formation is detected optically and time to clotting measured. Clotting time (seconds) is compared to the mean clotting time of FVII-deficient plasma alone and plotted as the fractional clotting time versus FVIIa analog concentration.
Therapeutic Proteins
The present invention further provides therapeutic agents comprising an elastic peptide component and at least one therapeutic protein selected from Table 1. The elastic peptide (e.g., ELP) component and therapeutic protein may be coupled by recombinant fusion or chemical conjugation as described herein. Such therapeutic proteins are listed in Table 1 by protein name and GeneSeq Accession No. The amino acid sequence of each Therapeutic Protein, which is known in the art, is hereby incorporated by reference for each Therapeutic Protein listed in Table 1. Such therapeutic proteins are further described in US patent or PCT publications that are also listed in Table 1, and such US patent and PCT publications are hereby incorporated by reference, especially with respect to the structure of such therapeutic proteins and described functional analogs.
Table 1 further describes the biological activity of each listed Therapeutic Protein, as well as an exemplary assay for determining the activity of functional analogs or agents of the invention (e.g., fusion with an elastic peptide component). Generally, functional analogs of therapeutic proteins listed in Table 1 may include functional fragments truncated at the N-terminus and/or C-terminus by from 1 to 10 amino acids, including by 1, 2, 3, 4 or about 5 amino acids. Functional analogs may contain from 1 to 10 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the base sequence (e.g., as listed in Table 1), and in each case retaining the full or partial biological activity (as listed in Table 1) of the therapeutic protein. For example, functional analogs may have 1, 2, 3, 4, or 5 amino acid insertions, deletions, and/or substitutions (collectively) with respect to the base sequence. Such activity may be confirmed or assayed using any available assay, including those described in the Table. In these or other embodiments, the therapeutic protein has at least about 75%, 80%, 85%, 90%, 95%, or 98% identity with the corresponding base sequence. The molecules may further comprise additional chemical modifications known for each in the art.
In some embodiments, the therapeutic protein (e.g., as selected from Table 1) has a size of less than about 25 kDa, or less than about 10 kDa, or less than about 5 kDa, and the corresponding therapeutic agent of the invention (e.g., comprising the ELP component) has a molecular weight of less than about 60 kDa, 55 kDa, 50 kDa, or 40 kDa.
Table 1 further lists preferred indications for each therapeutic protein, for which the corresponding therapeutic agent finds use, such as in a method for treatment or prevention related to such indication.
Conjugation and Coupling
The present invention provides therapeutic agents comprising an elastic peptide component and a therapeutic component, such as therapeutic proteins listed in herein, including Table 1, as well as a GLP-1 receptor agonists, insulin, Factor VII/VIIa, and functional analogs as described. Such agents may be prepared by recombinant technology and/or chemical coupling (e.g., conjugation).
A recombinantly-produced elastic peptide fusion protein, in accordance with certain embodiments of the invention, includes the elastic peptide component and the therapeutic component associated with one another by genetic fusion. For example, the fusion protein may be generated by translation of a polynucleotide encoding the therapeutic component cloned in-frame with the elastic peptide component (or vice versa). Such an elastic peptide fusion protein may contain one or more copies of the therapeutic component attached to the N-terminus and/or the C-terminus of the elastic peptide component. In some embodiments, the therapeutic proteinacious component is attached to both the N- and C-terminus of the elastic peptide component and the fusion protein may contain one or more equivalents of the therapeutic component on either or both ends of the elastic peptide component.
In certain embodiments, the elastic peptide component and the therapeutic components can be fused using a linker peptide of various lengths to provide greater physical separation and allow more spatial mobility between the fused portions, and thus maximize the accessibility of the therapeutic component, for instance, for binding to its cognate receptor. The linker peptide may consist of amino acids that are flexible or more rigid. For example, a flexible linker may include amino acids having relatively small side chains, and which may be hydrophilic. Without limitation, the flexible linker may contain a stretch of glycine and/or serine residues. More rigid linkers may contain, for example, more sterically hindering amino acid side chains, such as (without limitation) tyrosine or histidine. The linker may be less than about 50, 40, 30, 20, 10, or 5 amino acid residues. The linker can be covalently linked to and between an elastic peptide component and a therapeutic component, for example, via recombinant fusion.
The linker or peptide spacer may be protease-cleavable or non-cleavable. By way of example, cleavable peptide spacers include, without limitation, a peptide sequence recognized by proteases (in vitro or in vivo) of varying type, such as Tev, thrombin, factor Xa, plasmin (blood proteases), metalloproteases, cathepsins (e.g., GFLG, etc.), and proteases found in other corporeal compartments. In some embodiments employing cleavable linkers, the fusion protein (“the therapeutic agent”) may be inactive, less active, or less potent as a fusion, which is then activated upon cleavage of the spacer in vivo. Alternatively, where the therapeutic agent is sufficiently active as a fusion, a non-cleavable spacer may be employed. The non-cleavable spacer may be of any suitable type, including, for example, non-cleavable spacer moieties having the formula [(Gly)n-Ser]m (SEQ ID NO.: 22) where n is from 1 to 4, inclusive, and m is from 1 to 4, inclusive. Alternatively, a short elastic peptide sequence different than the backbone elastic peptide could be employed instead of a linker or spacer, while accomplishing the necessary effect.
In still other embodiments, the therapeutic agent is a recombinant fusion having a therapeutic component flanked on each terminus by an elastic peptide component. At least one of said elastic peptide components may be attached via a cleavable spacer, such that the therapeutic component is inactive, but activated in vivo by proteolytic removal of a single elastic peptide component. The resulting single elastic peptide fusion being active, and having an enhanced half-life (or other property described herein) in vivo.
In other embodiments, the present invention provides chemical conjugates of the elastic peptide component and the therapeutic component. The conjugates can be made by chemically coupling an elastic peptide component to a therapeutic component by any number of methods well known in the art (See e.g. Nilsson et al., 2005, Ann Rev Biophys Bio Structure 34: 91-118). In some embodiments, the chemical conjugate can be formed by covalently linking the therapeutic component to the elastic peptide component, directly or through a short or long linker moiety, through one or more functional groups on the therapeutic proteinacious component, e. g., amine, carboxyl, phenyl, thiol or hydroxyl groups, to form a covalent conjugate. Various conventional linkers can be used, e. g., diisocyanates, diisothiocyanates, carbodiimides, bis (hydroxysuccinimide) esters, maleimide-hydroxysuccinimide esters, glutaraldehyde and the like.
Non-peptide chemical spacers can additionally be of any suitable type, including for example, by functional linkers described in Bioconjugate Techniques, Greg T. Hermanson, published by Academic Press, Inc., 1995, and those specified in the Cross-Linking Reagents Technical Handbook, available from Pierce Biotechnology, Inc. (Rockford, Ill.), the disclosures of which are hereby incorporated by reference, in their respective entireties. Illustrative chemical spacers include homobifunctional linkers that can attach to amine groups of Lys, as well as heterobifunctional linkers that can attach to Cys at one terminus, and to Lys at the other terminus.
In certain embodiments, relatively small ELP components (e.g., ELP components of less than about 30 kDa, 25 kDa, 20 kDa, 15 kDa, or 10 kDa), that do not transition at room temperature (or human body temperature, e.g., Tt>37° C.), are chemically coupled or crosslinked. For example, two relatively small ELP components, having the same or different properties, may be chemically coupled. Such coupling, in some embodiments, may take place in vivo, by the addition of a single cysteine residue at or around the C-terminus of the ELP. Such ELP components may each be fused to one or more therapeutic components, so as to increase activity or avidity at the target.
Polynucleotides, Vectors, and Host Cells
In another aspect, the invention provides polynucleotides comprising a nucleotide sequence encoding the therapeutic agent of the invention. Such polynucleotides further comprise, in addition to sequences encoding the elastic peptide and therapeutic components, one or more expression control elements. For example, the polynucleotide, may comprise one or more promoters or transcriptional enhancers, ribosomal binding sites, transcription termination signals, and polyadenylation signals, as expression control elements. The polynucleotide may be inserted within any suitable vector, which may be contained within any suitable host cell for expression.
A vector comprising the polynucleotide can be introduced into a cell for expression of the therapeutic agent. The vector can remain episomal or become chromosomally integrated, as long as the insert encoding the therapeutic agent can be transcribed. Vectors can be constructed by standard recombinant DNA technology. Vectors can be plasmids, phages, cosmids, phagemids, viruses, or any other types known in the art, which are used for replication and expression in prokaryotic or eukaryotic cells. It will be appreciated by one of skill in the art that a wide variety of components known in the art (such as expression control elements) may be included in such vectors, including a wide variety of transcription signals, such as promoters and other sequences that regulate the binding of RNA polymerase onto the promoter. Any promoter known to be effective in the cells in which the vector will be expressed can be used to initiate expression of the therapeutic agent. Suitable promoters may be inducible or constitutive. Examples of suitable promoters include the SV40 early promoter region, the promoter contained in the 3′ long terminal repeat of Rous sarcoma virus, the HSV-1 (herpes simplex virus-1) thymidine kinase promoter, the regulatory sequences of the metallothionein gene, etc., as well as the following animal transcriptional control regions, which exhibit tissue specificity and have been utilized in transgenic animals: elastase I gene control region which is active in pancreatic acinar cells; insulin gene control region which is active in pancreatic beta cells, immunoglobulin gene control region which is active in lymphoid cells, mouse mammary tumor virus control region which is active in testicular, breast, lymphoid and mast cells, albumin gene control region which is active in liver, alpha-fetoprotein gene control region which is active in liver, alpha 1-antitrypsin gene control region which is active in the liver, beta-globin gene control region which is active in erythroid cells, myelin basic protein gene control region which is active in oligodendrocyte cells in the brain, myosin light chain-2 gene control region which is active in skeletal muscle, and gonadotropin releasing hormone gene control region which is active in the hypothalamus.
Pharmaceutical Compositions
The present invention further provides pharmaceutical compositions comprising the therapeutic agents of the invention (as described above) together with a pharmaceutically acceptable carrier or excipient. Such pharmaceutical compositions may be employed in the methods of treatment as described above, for each of the therapeutic proteins, e.g., the therapeutic proteins listed in Table 1, GLP-1 receptor agonists, insulin, and Factor VII/VIIa embodiments.
The therapeutic agents of the invention may overcome certain deficiencies of peptide agents when administered (e.g., parenterally), including in some embodiments, the limitation that such peptides may be easily metabolized by plasma proteases or cleared from circulation by kidney filtration. Traditionally, the oral route of administration of peptide agents may also be problematic, because in addition to proteolysis in the stomach, the high acidity of the stomach destroys such peptide agents before they reach their intended target tissue. Peptides and peptide fragments produced by the action of gastric and pancreatic enzymes are cleaved by exo and endopeptidases in the intestinal brush border membrane to yield di- and tripeptides, and even if proteolysis by pancreatic enzymes is avoided, polypeptides are subject to degradation by brush border peptidases. Any of the peptide agents that survive passage through the stomach are further subjected to metabolism in the intestinal mucosa where a penetration barrier prevents entry into the cells. In certain embodiments, the therapeutic agents of the invention may overcome such deficiencies, and provide compositional forms having enhanced efficacy, bioavailability, therapeutic half-life, persistence, degradation assistance, etc. The therapeutic agents of the invention thus include oral and parenteral dose forms, as well as various other dose forms, by which peptide agents can be utilized in a highly effective manner. For example, in some embodiments, such agents may achieve high mucosal absorption, and the concomitant ability to use lower doses to elicit an optimum therapeutic effect.
The therapeutic agents of the present invention may be administered in smaller doses and/or less frequently than unfused or unconjugated counterparts. While one of skill in the art can determine the desirable dose in each case, a suitable dose of the therapeutic agent for achievement of therapeutic benefit, may, for example, be in a range of about 1 microgram (μg) to about 100 milligrams (mg) per kilogram body weight of the recipient per day, preferably in a range of about 10 μg to about 50 mg per kilogram body weight per day and most preferably in a range of about 10 μg to about 50 mg per kilogram body weight per day. The desired dose may be presented as one dose or two or more sub-doses administered at appropriate intervals throughout the day. These sub-doses can be administered in unit dosage forms, for example, containing from about 10 μg to about 1000 mg, preferably from about 50 μg to about 500 mg, and most preferably from about 50 μg to about 250 mg of active ingredient per unit dosage form. Alternatively, if the condition of the recipient so requires, the doses may be administered as a continuous infusion.
The mode of administration and dosage forms will of course affect the therapeutic amount of the peptide active therapeutic agent that is desirable and efficacious for a given treatment application. For example, orally administered dosages can be at least twice, e.g., 2-10 times, the dosage levels used in parenteral administration methods.
The therapeutic agents of the invention may be administered per se as well as in various forms including pharmaceutically acceptable esters, salts, and other physiologically functional derivatives thereof. The present invention also contemplates pharmaceutical formulations, both for veterinary and for human medical use, which include therapeutic agents of the invention. In such pharmaceutical and medicament formulations, the therapeutic agents can be used together with one or more pharmaceutically acceptable carrier(s) therefore and optionally any other therapeutic ingredients. The carrier(s) must be pharmaceutically acceptable in the sense of being compatible with the other ingredients of the formulation and not unduly deleterious to the recipient thereof. The therapeutic agents are provided in an amount effective to achieve the desired pharmacological effect, as described above, and in a quantity appropriate to achieve the desired daily dose.
The formulations of the therapeutic agent include those suitable for parenteral as well as non-parenteral administration, and specific administration modalities include oral, rectal, buccal, topical, nasal, ophthalmic, subcutaneous, intramuscular, intravenous, transdermal, intrathecal, intra-articular, intra-arterial, sub-arachnoid, bronchial, lymphatic, vaginal, and intra-uterine administration. Formulations suitable for oral and parenteral administration are preferred.
When the therapeutic agent is used in a formulation including a liquid solution, the formulation advantageously can be administered orally or parenterally. When the therapeutic agent is employed in a liquid suspension formulation or as a powder in a biocompatible carrier formulation, the formulation may be advantageously administered orally, rectally, or bronchially.
When the therapeutic agent is used directly in the form of a powdered solid, the active agent can be advantageously administered orally. Alternatively, it may be administered bronchially, via nebulization of the powder in a carrier gas, to form a gaseous dispersion of the powder which is inspired by the patient from a breathing circuit comprising a suitable nebulizer device.
The formulations comprising the therapeutic agent of the present invention may conveniently be presented in unit dosage forms and may be prepared by any of the methods well known in the art of pharmacy. Such methods generally include the step of bringing the therapeutic agents into association with a carrier which constitutes one or more accessory ingredients. Typically, the formulations are prepared by uniformly and intimately bringing the therapeutic agent into association with a liquid carrier, a finely divided solid carrier, or both, and then, if necessary, shaping the product into dosage forms of the desired formulation.
Formulations suitable for oral administration may be presented as discrete units such as capsules, cachets, tablets, or lozenges, each containing a predetermined amount of the active ingredient as a powder or granules; or a suspension in an aqueous liquor or a non-aqueous liquid, such as a syrup, an elixir, an emulsion, or a draught.
A tablet may be made by compression or molding, optionally with one or more accessory ingredients. Compressed tablets may be prepared by compressing in a suitable machine, with the therapeutic agent being in a free-flowing form such as a powder or granules which optionally is mixed with a binder, disintegrant, lubricant, inert diluent, surface active agent, or discharging agent. Molded tablets comprised of a mixture of the powdered peptide active therapeutic agent-elastic peptide construct(s) with a suitable carrier may be made by molding in a suitable machine.
A syrup may be made by adding the peptide active therapeutic agent-ELP construct(s) to a concentrated aqueous solution of a sugar, for example sucrose, to which may also be added any accessory ingredient(s). Such accessory ingredient(s) may include flavorings, suitable preservative, agents to retard crystallization of the sugar, and agents to increase the solubility of any other ingredient, such as a polyhydroxy alcohol, for example glycerol or sorbitol.
Formulations suitable for parenteral administration conveniently comprise a sterile aqueous preparation of the therapeutic agent, which preferably is isotonic with the blood of the recipient (e.g., physiological saline solution). Such formulations may include suspending agents and thickening agents or other microparticulate systems which are designed to target the peptide active therapeutic agent to blood components or one or more organs. The formulations may be presented in unit-dose or multi-dose form.
Nasal spray formulations comprise purified aqueous solutions of the therapeutic agent with preservative agents and isotonic agents. Such formulations are preferably adjusted to a pH and isotonic state compatible with the nasal mucus membranes.
Formulations for rectal administration may be presented as a suppository with a suitable carrier such as cocoa butter, hydrogenated fats, or hydrogenated fatty carboxylic acid.
Topical formulations comprise the therapeutic agent dissolved or suspended in one or more media, such as mineral oil, petroleum, polyhydroxy alcohols, or other bases used for topical pharmaceutical formulations.
In addition to the aforementioned ingredients, the formulations of this invention may further include one or more accessory ingredient(s) selected from diluents, buffers, flavoring agents, disintegrants, surface active agents, thickeners, lubricants, preservatives (including antioxidants), and the like.
The features and advantages of the present invention are more fully shown with respect to the following non-limiting examples.
Cloning steps were conducted in Escherichia coli strain XL1-Blue (rec A1, endA1, gyrA96, thi-1, hsdR17 (rk−, mk+), supE44, relA1, lac[F′, proAB, /αclqZΔM15, Tn10 (Tetr)] (Stratagene La Jolla, Calif.). pUC19 (NEB, Beverly, Mass.) was used as the cloning vector for the ELP construction (Meyer and Chilkoti, Nat. Biotechnol., 17(11):1112-5, 1999). Modified forms of pET15b and pET24d vectors (Novagen) were used to express ELP and ELP-fusion proteins in BL21 Star (DE3) strain (F−, ompT, hsdSB (rB−mB−), gal, dcm, rne131, (DE3)) (Invitrogen Carlsbad, Calif.) or BLR(DE3) (F−, ompT, hsdSB (rB−mB−), gal, dcm, Δ(srl-recA) 306::Tn10(TcR)(DE3)) (Novagen Madison, Wis.). Synthetic DNA oligos were purchased from Integrated DNA Technologies, Coralville, Iowa. All vector constructs were made using standard molecular biology protocols (e.g., Current Protocols in Molecular Biology, ed. Ausubel, et al., 1995).
Construction of ELP1 [V5A2G3] Gene Series
The ELP1 [V5A2G3] series designate polypeptides containing multiple repeating units of the pentapeptide VPGXG (SEQ ID NO: 3), where X is valine, alanine, and glycine at a relative ratio of 5:2:3.
The ELP1 [V5A2G3] series monomer, ELP1 [V5A2G3-10], was created by annealing four 5′ phosphorylated, PAGE purified synthetic oligos to form double stranded DNA with EcoRI and HindIII compatible ends (Meyer and Chilkoti, Nat. Biotechnol., 17(11):1112-5, 1999). The oligos were annealed in a 1 μM mixture of the four oligos in 50 μl IX ligase buffer (Invitrogen) to 95° C. in a heating block than the block was allowed to cool slowly to room temperature. The ELP1 [V5A2G3-10]/EcoRI-HindIII DNA segment was ligated into a pUC19 vector digested with EcoRI and HindIII and CIAP dephosphorylated (Invitrogen) to form pUC19-ELP1 [V5A2G3-10]. Building of the ELP1 [V5A2G3] series library began by inserting ELP1 [V5A2G3-10] PflMI/BgII fragment from pUC19-ELP1 [V5A2G3-10] into pUC19-ELP1 [V5A2G3-10] linearized with PflMI and dephosphorylated with CIAP to create pUC19-ELP1 [V5A2G3-20]. pUC19-ELP1 [V5A2G3-20] was then built up to pUC19-ELP1 [V5A2G3-30] and pUC19-ELP1 [V5A2G3-40] by ligating ELP1 [V5A2G3-10] or ELP1 [V5A2G3-20] PflMI/BgII fragments respectively into PflMI digested pUC 19-ELP1 [V5A2G3-20]. This procedure was used to expand the ELP1 [V5A2G3] series to create pUC19-ELP1 [V5A2G3-60], pUC19-ELP1 [V5A2G3-90] and pUC19-ELP1 [V5A2G3-180] genes.
Construction of ELP1 [K1V2F1] Gene Series
The ELP1 [K1V2F1] series designate polypeptides containing multiple repeating units of the pentapeptide VPGXG (SEQ ID NO: 3), where X is lysine, valine, and phenylalanine at a relative ratio of 1:2:1.
The ELP1 [K1V2F1] series monomer, ELP1 [K1V2F1-4], was created by annealing two 5′ phosphorylated, PAGE purified synthetic oligos to form double stranded DNA with EcoRI and HindIII compatible ends (Meyer and Chilkoti, 1999). The oligos were annealed in a 1 μM mixture of the four oligos in 50 μl 1× ligase buffer (Invitrogen) to 95° C. in a heating block then the block was allowed to cool slowly to room temperature. The ELP1 [K1V2F1-4]/EcoRI-HindIII DNA segment was ligated into a pUC19 vector digested with EcoRI and HindIII and CIAP dephosphorylated (Invitrogen) to form pUC19-ELP1 [K1V2F1-4]. Building of the ELP1 [K1V2F1] series library began by inserting ELP1 [K1V2F1-4] PflM1/Bgl1 fragment from pUC19-ELP1 [K1V2F1-4] into pUC19-ELP1 [K1V2F1-4] linearized with PflM1 and dephosphorylated with CIAP to create pUC19-ELP1 [K1V2F1-8]. Using the same procedure the ELP1 [K1V2F1] series was doubled at each ligation to form pUC19-ELP1 [K1V2F1-I6], pUC19-ELP1 [K1V2F1-32], pUC19-ELP1 [K1V2F1-64] and pUC19-ELP1 [K1V2F1-128].
Construction of ELP1 [K1V7F1] Gene Series
The ELP1 [K1V7F1] series designate polypeptides containing multiple repeating units of the pentapeptide VPGXG (SEQ ID NO: 3), where X is lysine, valine, and phenylalanine at a relative ratio of 1:7:1.
The ELP1 [K1V7F1] series monomer, ELP1 [K1V7F1-9], was created by annealing four 5′ phosphorylated, PAGE purified synthetic oligos to form double stranded DNA with PflMI and HindIII compatible ends. The ELP1 [K1V7F1-9] DNA segment was than ligated into PflM1/HindIII dephosphorylated PUC19-ELP1 [V5A2G3-180] vector thereby substituting ELP1 [V5A2G3-180] for ELP1 [K1V7F1-9] to create the pUC19-ELP1 [K1V7F1-9] monomer. The ELP1 [K1V7F1] series was expanded in the same manner as the ELP1 [K1V2F1] series to create pUC19-ELP1 [K1V7F1-18], PUC19-ELP1 [K1V7F1-36], pUC19-ELP1 [K1V7F1-72] and pUC19-ELP1 [K1V7F1-144].
Construction of ELP1 [V] Gene Series
The ELP1 [V] series designate polypeptides containing multiple repeating units of the pentapeptide VPGXG (SEQ ID NO: 3), where X is exclusively valine.
The ELP1 [V] series monomer, ELP1 [V-5], was created by annealing two 5′ phosphorylated, PAGE purified synthetic oligos to form double stranded DNA with EcoRI and HindIII compatible ends. The ELP1 [V-5] DNA segment was than ligated into EcoRI/HindIII dephosphorylated pUC19 vector to create the pUC19-ELP1 [V-5] monomer. The ELP1 [V] series was created in the same manner as the ELP1 [V5A2G3] series, ultimately expanding pUC19-ELP1 [V-5] to pUC19-ELP1 [V-60] and pUC19-ELP1 [V-120].
Construction of ELP2 Gene Series
The ELP2 series designate polypeptides containing multiple repeating units of the pentapeptide AVGVP.
The ELP2 series monomer, ELP2 [5], was created by annealing two 5′ phosphorylated, PAGE purified synthetic oligos to form double stranded DNA with EcoRI and HindIII compatible ends. The ELP2 [5] DNA segment was than ligated into EcoRI/HindIII dephosphorylated pUC19 vector to create the pUC19-ELP2[5] monomer. The ELP2 series was expanded in the same manner as the ELP1 [K1V2F1] series to create pUC19-ELP2[10], pUC19-ELP2 [30], pUC 19-ELP2 [60] and pUC 19-ELP2 [120].
Construction of ELP3 [V] Gene Series
The ELP3 [V] series designate polypeptides containing multiple repeating units of the pentapeptide IPGXG (SEQ ID NO: 5), where X is exclusively valine.
The ELP3 [V] series monomer, ELP3 [V-5], was created by annealing two 5′ phosphorylated, PAGE purified synthetic oligos to form double stranded DNA with PfLM1 amino terminal and GGC carboxyl terminal compatible ends due to the lack of a convenient carboxyl terminal restriction site but still enable seamless addition of the monomer. The ELP3 [V-5] DNA segment was then ligated into PflM1/BgII dephosphorylated pUC19-ELP4[V-5], thereby substituting ELP4 [V-5] for ELP3 [V-5] to create the pUC19-ELP3 [V-5] monomer. The ELP3 [V] series was expanded by ligating the annealed ELP3 oligos into pUC19-ELP3[V-5] digested with PflMI. Each ligation expands the ELP3 [V] series by 5 to create ELP3 [V-10], ELP3 [V-15], etc.
Construction of the ELP4 [V] Gene Series
The ELP4 [V] series designate polypeptides containing multiple repeating units of the pentapeptide LPGXG (SEQ ID NO: 7), where X is exclusively valine.
The ELP4 [V] series monomer, ELP4 [V-5], was created by annealing two 5′ phosphorylated, PAGE purified synthetic oligos to form double stranded DNA with EcoRI and HindIII compatible ends. The ELP4 [V-5] DNA segment was than ligated into EcoRI/HindIII dephosphorylated pUC19 vector to create the pUC19-ELP4[V-5] monomer. The ELP4 [V] series was expanded in the same manner as the ELP1 [K1V2F1] series to create pUC19-ELP4[V-10], pUC19-ELP4[V-30], pUC19-ELP4[V-60] and pUC19-ELP4[V-120].
The ELP genes were also inserted into other vectors such as pET15b-SD0, pET15b-SD3, pET15b-SD5, pET15b-SD6, and pET24d-SD21. The pET vector series are available from Novagen, San Diego, Calif.
The pET15b-SD0 vector was formed by modifying the pET15b vector using SD0 double-stranded DNA segment containing the multicloning restriction site (SacI-NdeI-NcoI-XhoI-SnaBI-BamHI). The SD0 double-stranded DNA segment had XbaI and BamHI compatible ends and was ligated into XbaI/BamHI linearized and 5′-dephosphorylated pET15b to form the pet15b-SD0 vector.
The pET15b-SD3 vector was formed by modifying the pET15b-SD0 vector using SD3 double-stranded DNA segment containing a SfiI restriction site upstream of a hinge region-thrombin cleavage site followed by the multicloning site (NdeI-NcoI-XhoI-SnaBI-BamHI). The SD3 double-stranded DNA segment had SacI and NdeI compatible ends and was ligated into SacI/NdeI linearized and 5′-dephosphorylated pET15b-SD0 to form the pET15b-SD3 vector.
The pET15b-SD5 vector was formed by modifying the pET15b-SD3 vector using the SD5 double-stranded DNA segment containing a SM restriction site upstream of a thrombin cleavage site followed by a hinge and the multicloning site (NdeI-NcoI-XhoI-SnaBI-BamHI). The SD5 double-stranded DNA segment had SfiI and NdeI compatible ends and was ligated into SfiI/NdeI linearized and 5′-dephosphorylated pET15b-SD3 to form the pET15b-SD5 vector.
The pET15b-SD6 vector was formed by modifying the pET15b-SD3 vector using the SD6 double-stranded DNA segment containing a SfiI restriction site upstream of a linker region-TEV cleavage site followed by the multicloning site (NdeI-NcoI-XhoI-SnaBI-BamHI). The SD6 double-stranded DNA segment had SfiI and NheI compatible ends and was ligated into SfiI/NdeI linearized and 5′-dephosphorylated pET15b-SD3 to form the pET15b-SD6 vector.
The pET24d-SD21 vector was formed by modifying the pET24d vector using the SD21 double-stranded DNA segment with NcoI and NheI compatible ends. The SD21 double-stranded DNA segment was ligated into NcoI/NheI linearized and 5′ dephosphorylated pET24d to create the pET24d-SD21 vector, which contained a new multicloning site NcoI-SfiI-NheI-BamHI-EcoRI-SacI-SalI-HindIII-NotI-XhoI with two stop codons directly after the SfiI site for insertion and expression of ELP with the minimum number of extra amino acids.
The pUC19-ELP1 [V5A2G3-60], pUC19-ELP1 [V5A2G3-90], and pUC19-ELP1 [V5A2G3-180] plasmids produced in XL1-Blue were digested with PflMI and BgII, and the ELP-containing fragments were ligated into the SfiI site of the pET15b-SD3 expression vector as described hereinabove to create pET15b-SD3-ELP1 [V5A2G3-60], pET15b-SD5-ELP1 [V5A2G3-90] and pET15b-SD5-ELP1 [V5A2G3-180], respectively.
The pUC19-ELP1 [V5A2G3-90], pUC19-ELP1 [V5A2G3-180], pUC19-ELP1 [V-60] and pUC19-ELP1 [V-120] plasmids produced in XL1-Blue were digested with PflMI and BgII, and the ELP-containing fragments were ligated into the SfiI site of the pET15b-SD5 expression vector as described hereinabove to create pET15b-SD5-ELP1 [V5A2G3-90], pET15b-SD5-ELP1 [V5A2G3-180], pET15b-SD5-ELP1 [V-60] and pET15b-SD5-ELP1 [V-120], respectively.
The pUC19-ELP1 [V5A2G3-90] plasmid produced in XL1-Blue was digested with PflMI and BgII, and the ELP-containing fragment was ligated into the SfiI site of the pET15b-SD6 expression vector as described hereinabove to create pET15b-SD6-ELP1 [V5A2G3-90].
The pUC19-ELP1 [K1V2F1-64], and pUC19-ELP1 [K1V2F1-128] plasmids produced in XL1-Blue were digested with PflMI and BgII, and the ELP-containing fragments were ligated into the SfiI site of the pET24d-SD21 expression vector as described hereinabove to create pET24d-SD21-ELP1 [K1V2F1-64] and pET24d-SD21-ELP1 [K1V2F1-128], respectively.
The pUC19-ELP1 [K1V7F1-72] and pUC19-ELP1 [K1V7F1-144] plasmids produced in XL1-Blue were digested with PflMI and BgII, and the ELP-containing fragments were ligated into the SfiI site of the pET24d-SD21 expression vector as described hereinabove to create pET24d-SD21-ELP1 [K1V7F1-72], pET24d-SD21-ELP1 [K1V7F1-144], respectively.
The pUC19-ELP2[60] and pUC19-ELP2[120] plasmids produced in XL1-Blue were digested with NcoI and HindIII, and the ELP-containing fragments were ligated into the NcoI and HindIII sites of the pET24d-SD21 expression vector as described hereinabove to create pET24d-SD21-ELP2[60], pET24d-SD21-ELP2[120], respectively.
The pUC19-ELP4[V-60] and pUC19-ELP4[V-120] plasmids produced in XL1-Blue were digested with NcoI and HindIII, and the ELP-containing fragments were ligated into the NcoI and HindIII sites of the pET24d-SD21 expression vector as described hereinabove to create pET24d-SD21-ELP4[V-60], pET24d-SD21-ELP4[V-120], respectively.
ELP-InsA fusion proteins included the following:
Insulin A peptide and ELP1 [V-60] polypeptide with an enterokinase protease cleavage site therebetween.
Insulin A peptide and ELP1 [V5A2G3-90] polypeptide with an enterokinase protease cleavage site therebetween.
Insulin A peptide and ELP1 [V-120] polypeptide with an enterokinase protease cleavage site therebetween.
Insulin A peptide and ELP1 [V5A2G3-180] polypeptide with an enterokinase protease cleavage site therebetween.
A single colony of E. coli strain BLR (DE3) (Novagen) containing the respective ELP-InsA fusion protein was inoculated into 5 ml CircleGrow (Q-BIOgene, San Diego, Calif.) supplemented with 100 μg/ml ampicillin (Sigma) and grown at 37° C. with shaking at 250 rpm for 5 hours. The 5 ml culture was then inoculated into a 500 ml culture and allowed to grow at 25° C. for 16 hours before inducing with 1 mM IPTG for 4 hours at 25° C. The culture was harvested and suspended in 40 ml 20 mM Tris-HCl pH 7.4, 50 mM NaCl, 1 mM DTT and 1 Complete EDTA free Protease inhibitor pellet (Roche, Indianapolis, Ind.). Cells were lysed by ultrasonic disruption on ice for 3 minutes, which consisted of 10 seconds bursts at 35% power separated by 30 second cooling down intervals. Cell debris was removed by centrifugation at 20,000 g, 4° C. for 30 minutes.
Inverse phase transition was induced by adding NaCl to the cell lysate at room temperature to achieve a final concentration of 1.0 M therein, followed by centrifugation at 20,000 g for 15 minutes at room temperature. The resulting pellet contained the respective ELP-InsA fusion protein and non-specifically NaCl precipitated proteins.
The pellet was re-suspended in 40 ml ice-cold ml 20 mM Tris-HCl pH 7.4, 50 mM NaCl, 1 mM DTT and re-centrifuged at 20,000 g, 4° C. for 15 minutes to remove the non-specifically NaCl precipitated proteins. The inverse transition cycle was repeated two additional times to increase the purity of the respective ELP-InsA fusion protein and reduce the final volume to 0.5 ml.
The pharmacokinetics of ELP1 were determined by intravenously administering [14C]ELP1 to nude mice (Balb/c nu/nu) bearing a leg/flank FaDu xenograft and collecting blood samples at various time intervals after administration. The blood pharmacokinetics exhibited a characteristic distribution and elimination response for large macromolecules, which was well described by a bi-exponential process.
The plasma concentration time-course curve was fit to the analytical solution of a two-compartment model to approximate both an elimination and distribution response. Certain pharmakinetic parameters are shown in Table 1 below. The distribution volume of the ELP (1.338 μl) was nearly identical to the hypothetical plasma volume of 1.363 μl (Barbee, R. W., et al., Am. J. Physio. 263(3) (1992) R728-R733), indicating that the ELP did not rapidly distribute or bind to specific organs and tissues directly after administration. The AUC is a measure of the cumulative exposure to ELP in the central compartment or the blood plasma. The body clearance is defined as the rate of ELP elimination in the body relative to its plasma concentration and is the summation of clearance through all organs including the kidney, liver and others.
The mass transfer rate constants are from a standard two-compartment model (k1; from central to peripheral compartment; k2, from peripheral to central compartment; and ke, elimination from central compartment). The distribution volume (Vd), central compartment concentration time-course area under the curve (AUC) and body clearance (ClB) are displayed. Data are shown as the mean values (n=5, except Vd and initial plasma concentration (CO) was calculated from a similar cohort with n=3).
14C Labeled ELP1-150 and/or 14C Labeled ELP2-160
14C labeled ELP1-150 and/or 14C labeled ELP2-160 were administered to nude mice with a FaDu tumor (mean+/−SD, n=6). The tumor was heated post administration of the ELP in a water bath at 41.5° C. The distribution was highest to the organs with the highest blood content: liver, kidneys, spleen, and lungs.
14C Labeled ELP2-[V1A8G7-160]
14C labeled ELP2-[V1ABG7-160] (Tt>60° C.) was administered to nude mice for a plasma concentration of 15 μM. ELP concentrations were determined following 1 hour of heating (41° C.) of an implanted FaDu tumor, located in the right hind leg of the nude mouse. Data are shown as the mean, plus the 95% confidence interval. N=6.
ELP concentration was measured 1.5 hours following systemic administration of 14C labeled ELP2-[V1A8G7-160]. The highest distribution is seen in organs with the highest blood content: liver, kidneys, spleen, and lungs.
The DNA sequence for Exendin-4 (Ex-4) (SEQ ID NO: 14) was reverse translated from the amino acid sequence using codons optimized for E. coli expression. The DNA sequence encoding Exendin-4 was constructed by annealing together synthetic oligonucleotides with overhanging 5′ and 3′ ends compatible with the restriction sites NdeI and XhoI in the plasmid pET24d-ELP1-90 (
pET24d-Ex-4 ELP1-90 was used to transform the E. coli strain BRL (Invitrogen) and selected transformants were grown in media 3(1.2% Tryptone Peptone, 2.4% yeast extract, 5 g/L casamino acids, 2% glycerol, 2.313 g Potassium phosphate dibasic/L, 12.541 g Potassium phosphate monobasic/L) in shake flasks. Production proceeded by autoinduction by inoculating 1 OD cells into 1 L of media 3 and allowing growth to proceed for 17 hr at 37° C. without addition of inducer. The product was recovered by collection of the cell pellet, sonicated to disrupt the cells and recovered by thermal and/or salt induced transition modulated by the ELP moiety (Improved Non-chromatographic Purification of a Recombinant Protein by Cationic Elastin-like Polypeptides, Dong Woo Lim, Kimberly Trabbic-Carlson, J. Andrew MacKay, and Ashutosh Chilkoti. Biomacromolecules 2007, 8, 1417-1424).
This example is with the ELP designated 1-90. This is based on the VPGXG (SEQ ID NO: 3) motif where X is a V, G or A in the ratio 5:3:2 in a 10 unit repeat, repeated 8× with a final (C-terminal) 10-unit repeat where X is a V, G, A and W in the ratio 4:3:2:1.
[(VPGXG)10]9 where the X residue in the ten sequential iterations of the repeat unit (numerical subscript) can be described as [(V1, 4, 5, 6, 10G2, 7, 9A3, 8)8 (V1, 4, 5, 6G2, 7, 9A3, 8 W10)].
The ELP may be any combination of VPGXG (SEQ ID NO: 3) units where X is any of the 20 natural amino, acids, except proline, in any combination of repeat units of any length. In addition, the amino acid may be an unnatural amino acid for which the host strain has been engineered to accept an engineered tRNA for incorporation at specific codon (Wang L, Brock A, Herberich B, Schultz P G. Expanding the genetic code of Escherichia coli. [2001] Science 292, 498-500).
This construct was produced in the cytosol with an N-terminal methionine, which is normally removed by methionine aminopeptidase. Complete and accurate processing of the methionine, however, cannot be assumed; this enzyme may also remove the N-terminal histidine of the Exendin-4 moiety. This could result in a mixture of, unprocessed, processed and incorrectly processed products. Consequently, further constructs were developed to generate products with correctly processed N-termini.
Primers were designed to add a Tev protease (Tobacco Etch Virus cysteine protease) cleavage site between the N-terminal methionine and the histidine at the N-terminus of Exendin-4. This allows for removal of the methionine and the Tev recognition sequence to give the mature N-terminus of Exendin-4 (histidine). This can be done post-production or the Tev protease can be co-expressed to cleave the recognition sequence during production, for instance, as an intein (Ge, X., Yang, D. S. C., Trabbic-Carlson, K., Kim, B., Chilkoti, A. and Filipe, C. D. M. Self-Cleavable Stimulus Responsive Tags for Protein Purification without Chromatography. J. Am. Chem. Soc. 127, 11228-11229, 2005). The Tev Exendin-4 sequence is shown in
An alternative route to obtaining a correctly processed N-terminus for Ex-4 is to use a leader or signal sequence that directs the product to the periplasm and which is cleaved by a signal peptidase in the process. In this instance, a signal sequence, DsbA, that directs the transcript to the signal recognition particle for direct secretion of the polypeptide into the periplasm is given. (See
While this example illustrates the preparation of therapeutic agents with Exendin-4 sequences, such sequences can be replaced with GLP-1, insulin, Factor VII/VIIa, or other therapeutic protein listed in Table 1, generated in exactly or a similar manner as detailed for Exendin-4.
The ELP plasmid constructs were used to prepare two GLP1-ELP fusion proteins, GLP1(A8G,7-37)ELP1-90 and GLP1(A8G,7-37)ELP1-120. The plasmid constructs, fusion-encoding nucleotide sequence, as well as the amino acid sequence of the resulting fusion proteins are shown in
Both constructs contain an N-terminal Tev protease site to allow processing to the mature form where His7 of GLP1 is at the N-terminus. The processed fusion proteins have calculated molecular weights of about 39,536 and about 50,828, respectively.
The coagulation factor VII (FVII) gene was modified by PCR from a cDNA clone (Oragene) to add restriction sites at the 5′ and 3′ ends for cloning into the ELP-containing vector. At the 5′ end an NheI site was added and at the 3′ end a NotI site was added. The DNA and amino acid sequences of the Factor VII gene are shown in the accompanying Sequence Listing as SEQ ID NOS: 34 and 33, respectively. The DNA sequences of the 5′ and 3′ primers used to PCR amplify the factor VII (FVII) gene were:
The resulting PCR fragment was digested with the restriction enzymes NheI and NotI and ligated into the plasmid pcDNA3.1+ELP1-90 previously digested with the restriction enzymes NheI and NotI (
The resulting plasmid, pcDNA3.1+FVII-ELP1-90, was transiently transfected into HEK293 cells and culture media harvested. The ELP fusion was purified by phase transition (
The nucleotide and amino acid sequences of the FactorVII-ELP fusion is shown in
The cDNA for the human insulin gene is modified at the 5′ and 3′ ends for insertion in to pET24d-ELP1-90. The 5′ primer adds an N-terminal methionine for bacterial expression and an NdeI restriction enzyme site. The 3′ primer adds an XhoI restriction enzyme site. The PCR product and the plasmid are both digested with the restriction enzymes NdeI and XhoI and ligated together. The sequence of the insulin (Chains B, C, and A fused to ELP1 is shown in
Correct insertion is determined by restriction digest and DNA sequencing. The resulting plasmid, designated pET24d Insulin-ELP1-90, is shown in
The native insulin form is generated after recovery from E. coli by treatment with trypsin and carboxypeptidase B to remove the C-peptide chain.
For correct processing of the N-terminus of the B-chain similar modifications to those made for the Exendin-4 fusion (protease cleavage site, signal sequence) can be implemented (see Example 4). Alternatively, the first two residues can be Met-Arg, which can also be removed by trypsin digestion in production of the final material (R. M. Belagaje, S. G. Reams, S. C. Ly and W. F. Prouty, Increased production of low molecular weight recombinant proteins in Escherichia coli. Protein Sci. 6, 1953-1962, 1997).
Additional constructs would place the insulin cDNA at the 3′ end of the ELP for a C-terminal fusion, add linkers between the Insulin and ELP sequences, and/or use modified forms of insulin which have no C-peptide (single chain insulins as described) removing the need for additional processing.
A gene encoding a 50 amino acid sequence was constructed from chemically-synthesized oligonucleotides using standard molecular biology protocols. The 50 amino acid sequence contained 10 repeats of the pentapeptide VPGXG (SEQ ID NO: 3), where the guest residues (V, G, and A in a 5:3:2 molar ratio) were selected to provide a Tt of 40° C. The gene was oligomerized end-to-end by standard molecular biology techniques, to produce an oligomeric ELP gene. Additionally a single 50 amino acid sequence was constructed containing the 10 repeat pentapeptide VPGXG (SEQ ID NO: 3) polypeptide where the guest residues were V, G, A and C in a 4:3:2:1 molar ratio. This sequence could be added at any cycle of the oligomerization process to introduce a single cysteine residue into the final construct at a chosen point along the length of the construct.
The example given here is with the ELP designated 1-90. This is based on the VPGXG (SEQ ID NO: 3) motif where X is a V, G or A in the ratio 5:3:2 in a 10-unit repeat, repeated 8× with a final (C-terminal) 10-unit repeat where X is a V, G, A and C in the ratio 4:3:2:1, i.e., [(VPGXG)10]9 (SEQ ID NO.: 3).
Alternatively, the residue could be one of either arginine, lysine, aspartic acid or glutamic acid. The purpose of these amino acids is to provide a reactive side chain for the chemical conjugation of, for example, insulin. In this particular case the use of an ELP would be to extend the circulating half-life of the therapeutic protein (e.g., insulin) to provide prolonged basal glucose control. Conjugated to an ELP that transitions at body temperature, the insulin would form a precipitated depot at the site of injection in a similar manner to Lantus® (Sanofi Aventis) but without the requirement for formulation in acidic (pH 4.0) conditions with m-cresol for a more tolerable injection.
When administered to rats by i.v., Factor VII-ELP demonstrated a half-life of about 690 minutes. In contrast, Factor VII demonstrated a half-life of 45-60 minutes. Half-life in this example was measured by sandwich ELISA for FactorVII.
Also in contrast, the reported half-life for NovoSeven™ is 45 minutes, the reported half-life for FactorVIIa-albumin fusion is 263 minutes, and the reported half-life for Factor VIIa-PEG is 300 minutes in mice and 600 minutes in dog.
Activation of the GLP-1 receptor (GLP1R) results in production of cAMP secondary messenger within the cell. Therefore, GLP-1 or Exendin-4 analogs and corresponding therapeutic agents may be tested by their ability to activate GLP1R on the cell surface and produce cAMP.
For this bioassay CHO cells transfected with cDNA coding for GLP1R are used. These cells respond to stimulation by GLP-1 and produce high levels of cAMP. Log phase growing cells are plated and increasing concentrations of test compounds (e.g., therapeutic agent of the invention, or GLP-1 or exendin-4 functional analog) are added to the cells. After an appropriate incubation period (usually 15-60 min) in physiological buffer at 37° C. the cAMP produced is measured using a CatchPoint cAMP assay kit from Molecular Devices (Sunnyvale, Calif.). The EC50 of each test compound as compared to GLP-1 peptide or Exendin-4 peptide (or as compared to an unfused or unconjugated counterpart of a therapeutic agent of the invention) is indicative of the changes in activity due to a specific modifications introduced into the peptide, or due to particular chemical or recombinant coupling to an ELP component.
As shown in
The activity of GLP-1 or Exendin analogues or corresponding therapeutic agents may be tested in animals. For this assay, normal or diabetic animals may be used. Diabetic animals with blood glucose concentration 300-500 mg/dl are injected with different doses of GLP-1 or Exendin analogues or corresponding therapeutic agent, and changes in blood glucose monitored with a glucometer. The drop in glucose at different times points post administration is compared to that resulting with standard amounts of GLP-1 or Exendin-4 peptide, or compared to an unfused or unconjugated counterpart of a therapeutic agent of the invention. Alternatively, the blood glucose excursion in normal or diabetic animals during specific time period after administration of exogenous glucose is compared to GLP-1 or Exendin-4 (or to unfused or unconjugated counterparts of therapeutic agents). In this way the activity of the analogues and fusion proteins can be compared to the natural peptides.
All reference cited herein are hereby incorporated by reference in their entireties. While the invention has been has been described herein in reference to specific aspects, features and illustrative embodiments of the invention, it will be appreciated that the utility of the invention is not thus limited, but rather extends to and encompasses numerous other variations, modifications and alternative embodiments, as will suggest themselves to those of ordinary skill in the field of the present invention, based on the disclosure herein.
This application is a continuation of U.S. application Ser. No. 12/852,365, filed Aug. 6, 2010, which is a continuation-in-part of , U.S. application Ser. No. 12/493,912, filed Jun. 29, 2009, now U.S. Pat. No. 8,178,495, which claims priority to U.S. Provisional Application No. 61/076,221, filed Jun. 27, 2008, each of which is hereby incorporated by reference in its entirety. U.S. application Ser. No. 12/852,365 is also a continuation-in-part of U.S. application Ser. No. 12/158,190, now U.S. Pat. No. 8,334,257, which is a U.S. national stage of PCT/US06/048572, filed Dec. 20, 2006, which claims priority to U.S. Provisional Application No. 60/751,896, filed Dec. 20, 2005, each of which is hereby incorporated by reference in its entirety.
This invention was made with Government support under grant number EB00188 and GM-061232 from National Institutes of Health. The US Government has certain rights to this invention.
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| Number | Date | Country | |
|---|---|---|---|
| 20150080306 A1 | Mar 2015 | US |
| Number | Date | Country | |
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| 61076221 | Jun 2008 | US | |
| 60751896 | Dec 2005 | US |
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| Parent | 12852365 | Aug 2010 | US |
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| Parent | 12493912 | Jun 2009 | US |
| Child | 12852365 | US | |
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| Child | 12852365 | Aug 2010 | US |
