Patent Grant
9926351
10002.11 The instant application contains a Sequence Listing which has been submitted in ASCII format via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Aug. 31, 2016, is named 32808.720.302.txt and is 7,133,694 bytes in size.
Biologically active proteins including those as therapeutics are typically labile molecules exhibiting short shelf-lives, particularly when formulated in aqueous solutions. In addition, many biologically active peptides and proteins have limited solubility, or become aggregated during recombinant productions, requiring complex solubilization and refolding procedures. Various chemical polymers can be attached to such proteins to modify their properties. Of particular interest are hydrophilic polymers that have flexible conformations and are well hydrated in aqueous solutions. A frequently used polymer is polyethylene glycol (PEG). These polymers tend to have large hydrodynamic radii relative to their molecular weight (Kubetzko, S., et al. (2005) Mol Pharmacol, 68: 1439-54), and can result in enhanced pharmacokinetic properties. Depending on the points of attachment, the polymers tend to have limited interactions with the protein that they have been attached to such that the polymer-modified protein retains its relevant functions. However, the chemical conjugation of polymers to proteins requires complex multi-step processes. Typically, the protein component needs to be produced and purified prior to the chemical conjugation step. In addition, the conjugation step can result in the formation of heterogeneous product mixtures that need to be separated, leading to significant product loss. Alternatively, such mixtures can be used as the final pharmaceutical product, but are difficult to standardize. Some examples are currently marketed PEGylated Interferon-alpha products that are used as mixtures (Wang, B. L., et al. (1998) J Submicrosc Cytol Pathol, 30: 503-9; Dhalluin, C., et al. (2005) Bioconjug Chem, 16: 504-17). Such mixtures are difficult to reproducibly manufacture and characterize as they contain isomers with reduced or no therapeutic activity.
Albumin and immunoglobulin fragments such as Fc regions have been used to conjugate other biologically active proteins, with unpredictable outcomes with respect to increases in half-life or immunogenicity. Unfortunately, the Fc domain does not fold efficiently during recombinant expression and tends to form insoluble precipitates known as inclusion bodies. These inclusion bodies must be solubilized and functional protein must be renatured. This is a time-consuming, inefficient, and expensive process that requires additional manufacturing steps and often complex purification procedures.
Thus, there remains a significant need for compositions and methods that would improve the biological, pharmacological, safety, and/or pharmaceutical properties of a biologically active protein.
The present disclosure is directed to compositions and methods that can be useful for enhancing the biological, pharmaceutical, safety and/or therapeutic properties of biologically active proteins. The compositions and methods are particularly useful for enhancing the pharmacokinetic properties, such as half-life, and increasing the time spent within the therapeutic window of a biologically active protein, as well as simplifying the production process and pharmaceutical properties, such as solubility, of such a biologically active protein.
In part, the present disclosure is directed to pharmaceutical compositions comprising fusion proteins and the uses thereof for treating diseases, disorders or conditions. The particular disease to be treated will depend on the choice of the biologically active proteins. In some embodiments, the compositions and methods are useful for treating metabolic and cardiovascular diseases (including but not limited to glucose- or insulin-related diseases), coagulation and bleeding disorders, and growth-hormone related disorders.
In one aspect, the present invention provides compositions of extended recombinant polypeptides (XTENs), that when linked to a biologically active protein enhances the pharmacokinetic properties, and/or increases the solubility and stability of the resulting fusion protein, while retaining or enhancing overall biologic and/or therapeutic activity of the biologically active protein. Such compositions may have utility to treat certain diseases, disorders or conditions, as described herein. The resulting fusion protein can exhibit a better safety profile and permit less frequent dosing, which in turn can lead to better patient compliance. The present invention also provides polynucleotides encoding the XTEN and the fusion proteins of biologically active proteins linked with XTEN, as well as polynucleotides complementary to polynucleotides that encode the XTEN and the fusion proteins of biologically active proteins linked with XTEN.
In another aspect, the present invention provides compositions of extended recombinant polypeptides (XTEN) that are useful as fusion partners that can be linked to biologically active proteins (BPs), resulting in monomeric BPXTEN fusion proteins.
In one embodiment, the invention provides an isolated extended recombinant polypeptide (XTEN) comprising greater than about 400 to about 3000 amino acid residues, wherein the XTEN is characterized in that the sum of glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P) residues constitutes more than about 80%, or about 85%, or about 90%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% of the total amino acid sequence of the XTEN, the XTEN sequence is substantially non-repetitive, the XTEN sequence lacks a predicted T-cell epitope when analyzed by TEPITOPE algorithm, wherein the TEPITOPE algorithm prediction for epitopes within the XTEN sequence is based on a score of −5, or −6, or −7, or −8, or −9 or greater, the XTEN sequence has greater than 90%, or greater than 91%, or greater than 92%, or greater than 93%, or greater than 94%, or greater than 95%, or greater than 96%, or greater than 96%, or greater than 98%, or greater than 99% random coil formation as determined by GOR algorithm, and the XTEN sequence has less than 2% alpha helices and 2% beta-sheets as determined by Chou-Fasman algorithm.
In another embodiment, the invention provides XTEN comprising greater than about 400 to about 3000 amino acid residues, wherein the XTEN is characterized in that the sum of asparagine and glutamine residues is less than 10% of the total amino acid sequence of the XTEN, the sum of methionine and tryptophan residues is less than 2% of the total amino acid sequence of the XTEN, the XTEN sequence has less than 5% amino acid residues with a positive charge, the XTEN sequence has greater than 90% random coil formation as determined by GOR algorithm and the XTEN sequence has less than 2% alpha helices and 2% beta-sheets as determined by Chou-Fasman algorithm.
In another embodiment, the invention provides XTEN comprising greater than about 400 to about 3000 amino acid residues, wherein the XTEN is characterized in that at least about 80%, or at least about 90° %, or at least about 91%, or at least about 92%, or at least about 93%, or at least about 94%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99% of the XTEN sequence consists of non-overlapping sequence motifs wherein each of the sequence motifs has about 9 to about 14 amino acid residues and wherein the sequence of any two contiguous amino acid residues does not occur more than twice in each of the sequence motifs the sequence motifs consist of four to six types of amino acids selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and the XTEN enhances pharmacokinetic properties of a biologically active protein when linked to the biologically active protein wherein the pharmacokinetic properties are ascertained by measuring the terminal half-life of the biologically active protein administered to a subject in comparison to the XTEN linked to the biologically active protein and administered to a subject at a comparable dose.
In some cases of the foregoing embodiments, no one type of amino acid constitutes more than 30% of the XTEN sequence. In other cases of the foregoing embodiments, the XTEN can have a sequence in which no three contiguous amino acids are identical unless the amino acid is serine, in which case no more than three contiguous amino acids are serine residues. In other cases of the foregoing embodiments, the XTEN sequence has a subsequence score of less than 10, or 9, or 8, or 7, or 6. In still other cases of the foregoing embodiments, at least about 80%, or about 90%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99%, or 100% of the XTEN sequence consists of non-overlapping sequence motifs, wherein each of the sequence motifs has 12 amino acid residues. In one embodiment, the XTEN sequence consists of non-overlapping sequence motifs, wherein the sequence motifs are from one or more sequences of Table 1.
In some embodiments, the enhanced pharmacokinetic property of the resulting fusion protein encompasses an increase in terminal half-life of at least about two fold, or at least about three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold, or at least about eight-fold, or at least about ten-fold. In some cases, the enhanced pharmacokinetic property is reflected by the fact that the blood concentrations that remain within the therapeutic window for the fusion protein for a given period are at least about two fold, or at least about three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold, or at least about eight-fold, or at least about ten-fold longer compared to the corresponding BP not linked to XTEN. The increase in half-life and time spent within the therapeutic window can permit less frequent dosing and decreased amounts of the fusion protein (in moles equivalent) that are administered to a subject, compared to the corresponding BP not linked to XTEN. In one embodiment, the therapeutically effective dose regimen results in a gain in time of at least two-fold, or at least three-fold, or at least four-fold, or at least five-fold, or at least six-fold, or at least eight-fold, or at least 10-fold between at least two consecutive Cmax peaks and/or Cmin troughs for blood levels of the fusion protein compared to the corresponding BP not linked to the fusion protein and administered using a comparable dose regimen to a subject.
In one embodiment, at least about 80%, at least about 85%, at least about 90%, at least about 95%, or about 99% of the XTEN comprises motifs selected from one or more sequences of Table 1. In another embodiment, an XTEN exhibits at least about 80%, or at least about 90%, or at least about 91%, or at least about 92%, or at least about 93%, or at least about 94%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99% or 100% sequence identity to a sequence selected from Table 2
In some cases, the XTEN enhances thermostability of a biologically active protein when linked to the biologically active protein wherein the thermostability is ascertained by measuring the retention of biological activity after exposure to a temperature of about 37° C. for at least about 7 days of the biologically active protein in comparison to the XTEN linked to the biologically active protein. In one embodiment of the foregoing, the retention of biological activity is increased by at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 100%, or about 150%, at least about 200%, at least about 300%, or about 500% longer compared to the BP not linked to the XTEN comprises of the XTEN.
In another aspect, the invention provides an isolated fusion protein comprising an XTEN of any of the foregoing embodiments linked to a biologically active protein (BP). In some embodiments, the BP of the fusion protein exhibits at least about 80%, or at least about 90%, or at least about 91%, or at least about 92%, or at least about 93%, or at least about 94%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99% or 100% sequence identity to a sequence selected from Table 3, Table 4. Table 5, Table 6, Table 7, and Table 8. In another embodiment of the foregoing, the isolated fusion protein further comprises a second XTEN sequence wherein the cumulative total of amino acid residues in the XTEN sequences is greater than about 400 to about 3000 residues.
In some cases, the isolated fusion protein with an XTEN of one of the foregoing embodiments comprises a BP wherein the BP is a glucose regulating peptide. In one embodiment of the foregoing, the glucose regulating peptide is exendin-4. In another embodiment of the foregoing, the glucose regulating peptide is glucagon.
In other cases, the isolated fusion protein comprises a BP wherein the BP is a metabolic protein. In one embodiment of the foregoing, the metabolic protein is IL-1ra.
In still other cases, the isolated fusion protein comprises a BP wherein the BP is a coagulation factor. In one embodiment of the foregoing, the coagulation factor is factor IX. In another embodiment of the foregoing, the coagulation factor is factor VII.
In other cases, the isolated fusion protein comprises a BP wherein the BP is growth hormone.
In one embodiment, the isolated fusion protein can be less immunogenic compared to the biologically active protein not linked to the XTEN, wherein immunogenicity is ascertained by measuring production of IgG antibodies selectively binding to the biologically active protein after administration of comparable doses to a subject.
The fusion protein comprising XTEN and BP of the foregoing embodiments can comprise a spacer sequence between the BP and XTEN, wherein the spacer sequence comprises between about 1 to about 50 amino acid residues that optionally comprises a cleavage sequence. In one embodiment, the cleavage sequence is susceptible to cleavage by a protease. Non-limiting examples of such protease include FXIa, FXIIa, kallikrein, FVIIa, FIXa, FXa, thrombin, elastase-2, granzyme B, MMP-12, MMP-13, MMP-17 or MMP-20, TEV, enterokinase, rhinovirus 3C protease, and sortase A.
In some cases, the isolated fusion protein is configured to have reduced binding affinity for a target receptor of the corresponding BP, as compared to the corresponding BP not linked to the fusion protein. In one embodiment, the fusion protein exhibits binding for a target receptor of the BP in the range of about 0.01%-30%, or about 0.1% to about 20%, or about 1% to about 15%, or about 2% to about 10% of the binding capability of the corresponding BP that is not linked to the fusion protein. In a related embodiment, a fusion protein with reduced affinity can have reduced receptor-mediated clearance and a corresponding increase in half-life of at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or at least about 100%, or at least about 150%, or at least about 200%, or at least about 300%, or at least about 500% compared to the corresponding BP that is not linked to the fusion protein.
In one embodiment, the invention provides an isolated fusion protein that exhibits at least about 80%, or at least about 90%, or at least about 91%, or at least about 92%, or at least about 93%, or at least about 94%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99%, or 100% sequence identity to a sequence selected from Table 40, Table 41, Table 42, Table 43, and Table 44.
In one embodiment, the invention provides compositions comprising a fusion protein, wherein the fusion protein comprises at least a first BP comprising a sequence that exhibits at least about 80% sequence identity, or 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a sequence from any one of Tables 3-8, wherein the BP is linked to one or more extended recombinant polypeptides (XTEN) each comprising greater than about 100 to about 3000 amino acid residues, more preferably greater than about 400 to about 3000 amino acid residues, with a substantially non-repetitive sequence wherein the sum of glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P) residues constitutes more than about 80%, or about 85%, or about 90%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% of the total amino acid sequence of the XTEN. The XTEN component of the BPXTEN can lack a predicted T-cell epitope when analyzed by TEPITOPE algorithm, wherein the TEPITOPE algorithm prediction for epitopes within the XTEN sequence is based on a score of −7 or greater, or −8 or greater, or −9 or greater. The XTEN component of the BPXTEN can have a sequence with greater than 80%, or about 85%, or about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% random coil formation as determined by GOR algorithm; and the XTEN sequence can have less than 2% alpha helices and 2% beta-sheets as determined by Chou-Fasman algorithm.
In some embodiments, the invention provides BPXTEN fusion proteins wherein the BPXTEN administered to a subject exhibits an increase in the terminal half-life for the BPXTEN compared to the corresponding BP not linked to the fusion protein of at least about two-fold longer, or at least about three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold, or at least about seven-fold, or at least about eight-fold, or at least about nine-fold, or at least about ten-fold, or at least about 15-fold, or at least a 20-fold or greater increase in terminal half-life compared to the BP not linked to the fusion protein.
In some embodiments, the invention provides BPXTEN fusion proteins wherein the BPXTEN exhibits increased solubility of at least three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold, or at least about seven-fold, or at least about eight-fold, or at least about nine-fold, or at least about ten-fold, or at least about 15-fold, or at least a 20-fold, or at least 40-fold, or at least 60-fold at physiologic conditions compared to the BP not linked to the fusion protein.
In some embodiments, BPXTEN fusion proteins exhibit an increased apparent molecular weight as determined by size exclusion chromatography, compared to the actual molecular weight, wherein the apparent molecular weight is at least about 100 kD, or at least about 150 kD, or at least about 200 kD, or at least about 300 kD, or at least about 400 kD, or at least about 500 kD, or at least about 600 kD, or at least about 700 kD, while the actual molecular weight of each BP component of the fusion protein is less than about 25 kD. Accordingly, the BPXTEN fusion proteins can have an Apparent Molecular Weight that is about 4-fold greater, or about 5-fold greater, or about 6-fold greater, or about 7-fold greater, or about 8-fold greater than the actual molecular weight of the fusion protein. In some cases, the isolated fusion protein of the foregoing embodiments exhibits an apparent molecular weight factor under physiologic conditions that is greater than about 4, or about 5, or about 6, or about 7, or about 8.
The invention provides BPXTEN in various configurations wherein the BP retains at least a portion of the biologic activity of the corresponding BP not linked to XTEN. In one embodiment, the BPXTEN comprises a BP linked to an XTEN in the configuration of formula I
(BP)-(S)x-(XTEN) I
wherein independently for each occurrence, BP is a biologically active protein as described hereinabove; S is a spacer sequence having between 1 to about 50 amino acid residues that can optionally include a cleavage sequence (as described above), x is either 0 or 1; and XTEN is an extended recombinant polypeptide (as described herein). The embodiment has particular utility where the BP requires a free N-terminus for desired biological activity or where linking of the C-terminus of the BP to the fusion protein reduces biological activity and it is desired to reduce the biological activity and/or side effects of the administered BPXTEN.
In another embodiment of the BPXTEN configuration, the invention provides a fusion protein in the configuration of formula II (components as described above):
(XTEN)-(S)x-(BP) II
The embodiment is particularly useful where the BP requires a free C-terminus for desired biological activity, or where linking of the N-terminus of the BP to the fusion protein reduces biological activity and it is desired to reduce the biological activity and/or side effects of the administered BPXTEN.
In another aspect, the invention provides isolated BPXTEN fusion proteins comprising two molecules of the BP and optionally comprising a second XTEN and/or a spacer sequence wherein the fusion protein has a configuration selected from formula III, formula IV, and formula V:
(BP)-(S)w-(XTEN)-(S)x-(BP)-(S)y-(XTEN)z III
(XTEN)-(S)w-(BP)-(S)x-(XTEN)y-(BP) IV
(BP)-(S)x-(BP)-(S)y-(XTEN) V
wherein independently for each occurrence BP is a is a biologically active protein as described hereinabove, S is a spacer sequence having between 1 to about 50 amino acid residues that optionally comprises a cleavage sequence; w is either 0 or 1; x is either 0 or 1; y is either 0 or 1; z is either 0 or 1; and XTEN is an extended recombinant polypeptide (as described herein) wherein the cumulative total of XTEN amino acid residues is greater than 400 to about 3000.
In another aspect, the invention provides isolated fusion proteins comprising one molecule of the BP and two molecules of XTEN and optionally one or two spacer sequences, wherein the fusion protein is of formula VI:
(XTEN)-(S)x-(BP)-(S)y-(XTEN) VI
wherein independently for each occurrence BP is a biologically active protein, S is a spacer sequence having between 1 to about 50 amino acid residues that optionally comprises a cleavage sequence: w is either 0 or 1; x is either 0 or 1; y is either 0 or 1: z is either 0 or 1; and XTEN is an extended recombinant polypeptide (as described herein) wherein the cumulative total of XTEN amino acid residues is greater than 400 to about 3000.
Thus, the fusion proteins can be designed to have different configurations, N- to C-terminus, of a BP, XTEN, and optional spacer sequences, including but not limited to XTEN-BP, BP-XTEN, XTEN-S-BP, BP-S-XTEN, XTEN-BP-XTEN, BP-BP-XTEN, XTEN-BP-BP, BP-S-BP-XTEN, and XTEN-BP-S-BP. The choice of configuration can, as disclosed herein, confer particular pharmacokinetic, physico/chemical, or pharmacologic properties.
In one embodiment, the BPXTEN fusion proteins of formulas I, II, III, IV, or V, or VI described above exhibit a biological activity of at least about 40%, or at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or at least about 95% of the biological activity compared to the BP not linked to the fusion protein. In another embodiment, the BPXTEN fusion proteins of formula I, II, III, IV, or V bind the same receptors or ligands as the corresponding parental biologically active protein that is not covalently linked to the fusion protein.
The invention provides isolated nucleic acids comprising a polynucleotide sequence selected from (a) a polynucleotide encoding the fusion protein of any of the foregoing embodiments, or (b) the complement of the polynucleotide of (a). In one embodiment of the foregoing, the isolated nucleic acid comprises a polynucleotide sequence that has at least 80% sequence identity, or about 85%, or at least about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% to about 100% sequence identity to (a) a polynucleotide sequence that encodes a polypeptide selected from Table 40, Table 41, Table 42, Table 43, and Table 44: or (b) the complement of the polynuclcotide of (a). The invention provides expression vectors comprising the nucleic acid of any of the embodiments hereinabove described in this paragraph. In one embodiment, the expression vector of the foregoing further comprises a recombinant regulatory sequence operably linked to the polynucleotide sequence. In another embodiment, the polynucleotide sequence of the expression vectors of the foregoing is fused in frame to a polynucleotide encoding a secretion signal sequence, which can be a prokaryotic signal sequence. In one embodiment, the secretion signal sequence is selected from OmpA, DsbA, and PhoA signal sequences.
The invention provides a host cell, which can comprise an expression vector disclosed in the foregoing paragraph. In one embodiment, the host cell is a prokaryotic cell. In another embodiment, the host cell is E. coli.
In one embodiment, the invention provides pharmaceutical compositions comprising the fusion protein of any of the foregoing embodiments and at least one pharmaceutically acceptable carrier. In another embodiment, the invention provides kits, comprising packaging material and at least a first container comprising the pharmaceutical composition of the foregoing embodiment and a label identifying the pharmaceutical composition and storage and handling conditions, and a sheet of instructions for the reconstitution and/or administration of the pharmaceutical compositions to a subject.
The invention further provides use of the pharmaceutical compositions comprising the fusion protein of any of the foregoing embodiments in the preparation of a medicament for treating a disease condition in a subject in need thereof. In one embodiment of the foregoing, the disease, disorder or condition, comprising administering the pharmaceutical composition described above to a subject in need thereof. In one embodiment of the foregoing, the disease, disorder or condition is selected from type 1 diabetes, type 2 diabetes, obesity, hyperglycemia, hyperinsulinemia, decreased insulin production, insulin resistance, syndrome X, hibernating myocardium or diabetic cardiomyopathy, excessive appetite, insufficient satiety, metabolic disorder, glucagonomas, polycystic ovary syndrome, dyslipidemia, hibernating myocardium, insufficient urinary sodium excretion, excessive urinary potassium concentration, conditions or disorders associated with toxic hypervolemia, diabetic cardiomyopathy, and retinal neurodegenerative processes. In some cases, the pharmaceutical composition can be administered subcutaneously, intramuscularly, or intravenously. In one embodiment, the pharmaceutical composition is administered at a therapeutically effective dose. In some cases of the foregoing, the therapeutically effective dose results in a gain in time spent within a therapeutic window for the fusion protein compared to the corresponding BP of the fusion protein not linked to the fusion protein and administered at a comparable dose to a subject. The gain in time spent within the therapeutic window can at least three-fold greater than the corresponding BP not linked to the fusion protein, or alternatively, at least four-fold, or five-fold, or six-fold, or seven-fold, or eight-fold, or nine-fold, or at least 10-fold, or at least 20-fold greater than the corresponding BP not linked to the fusion protein.
In another embodiment, invention provides a method of treating a disease, disorder or condition, comprising administering the pharmaceutical composition described above to a subject using multiple consecutive doses of the pharmaceutical composition administered using a therapeutically effective dose regimen. In one embodiment of the foregoing, the therapeutically effective dose regimen can result in a gain in time of at least three-fold, or alternatively, at least four-fold, or five-fold, or six-fold, or seven-fold, or eight-fold, or nine-fold, or at least 10-fold, or at least 20-fold between at least two consecutive Cmax peaks and/or Cmin troughs for blood levels of the fusion protein compared to the corresponding BP of the fusion protein not linked to the fusion protein and administered at a comparable dose regimen to a subject. In another embodiment of the foregoing, the administration of the fusion protein results in a comparable improvement in at least one measured parameter using less frequent dosing or a lower total dosage in moles of the fusion protein of the pharmaceutical composition compared to the corresponding biologically active protein component(s) not linked to the fusion protein and administered to a subject d using a therapeutically effective regimen to a subject. The parameter can be selected from fasting glucose level, response to oral glucose tolerance test, peak change of postprandial glucose from baseline, HA1c, caloric intake, satiety, rate of gastric emptying, insulin secretion, peripheral insulin sensitivity, response to insulin challenge, beta cell mass, body weight, prothrombin time, bleeding time, thrombin-antithrombin III complex (TAT), D-dimer, incidence of bleeding episodes, erythrocyte sedimentation rate (ESR), C-reactive protein, bone density, muscle mass, blood pressure, plasma triglycerides, HDL, cholesterol, LDL cholesterol, incidence of angina, and cardiac output.
In another aspect, the invention provides a method of improving a property of a biologically active protein, comprising the step of linking a biologically active protein to the XTEN of any of the foregoing embodiments to achieve a property characterized in that (a) terminal half-life of the biologically active protein linked to the XTEN is longer as compared to the terminal half-life of the biologically active protein that is not linked to the XTEN; (b) shelf-life of the biologically active protein linked to the XTEN is longer as compared to the shelf-life of the biologically active protein that is not linked to the XTEN, wherein shelf-life is ascertained by retention of biological activity after an interval compared to a baseline sample: (c) solubility under physiologic conditions of the biologically active protein linked to the XTEN is increased as compared to the solubility of the biologically active protein that is not linked to the XTEN; (d) production of IgG antibodies selectively binding to the biologically active protein linked to the XTEN when administered to a subject is reduced as compared to production of the IgG when the biologically active protein not linked to the XTEN is administered to a subject at a comparable dose, and/or (e) time spent within the therapeutic window of the biologically active protein linked to the XTEN when administered to a subject is longer as compared to the biologically active protein that is not linked to the XTEN when administered to a subject.
All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.
The features and advantages of the invention may be further explained by reference to the following detailed description and accompanying drawings that sets forth illustrative embodiments.
Before the embodiments of the invention are described, it is to be understood that such embodiments are provided by way of example only, and that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention.
As used herein, the following terms have the meanings ascribed to them unless specified otherwise.
As used in the specification and claims, the singular forms “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a cell” includes a plurality of cells, including mixtures thereof.
The terms “polypeptide”, “peptide”, and “protein” are used interchangeably herein to refer to polymers of amino acids of any length. The polymer may be linear or branched, it may comprise modified amino acids, and it may be interrupted by non-amino acids. The terms also encompass an amino acid polymer that has been modified, for example, by disulfide bond formation, glycosylation, lipidation, acetylation, phosphorylation, or any other manipulation, such as conjugation with a labeling component.
As used herein the term “amino acid” refers to either natural and/or unnatural or synthetic amino acids, including but not limited to glycine and both the D or L optical isomers, and amino acid analogs and peptidomimetics. Standard single or three letter codes are used to designate amino acids.
The term “natural L-amino acid” means the L optical isomer forms of glycine (G), proline (P), alanine (A), valine (V), leucine (L), isoleucine (I), methionine (M), cysteine (C), phenylalanine (F), tyrosine (Y), tryptophan (W), histidine (H), lysine (K), arginine (R), glutamine (Q), asparagine (N), glutamic acid (E), aspartic acid (D), serine (S), and threonine (T).
The term “non-naturally occurring,” as applied to sequences and as used herein, means polypeptide or polynucleotide sequences that do not have a counterpart to, are not complementary to, or do not have a high degree of homology with a wild-type or naturally-occurring sequence found in a mammal. For example, a non-naturally occurring polypeptide may share no more than 99%, 98%, 95%, 90%, 80%, 70%, 60%, 50% or even less amino acid sequence identity as compared to a natural sequence when suitably aligned.
The terms “hydrophilic” and “hydrophobic” refer to the degree of affinity that a substance has with water. A hydrophilic substance has a strong affinity for water, tending to dissolve in, mix with, or be wetted by water, while a hydrophobic substance substantially lacks affinity for water, tending to repel and not absorb water and tending not to dissolve in or mix with or be wetted by water. Amino acids can be characterized based on their hydrophobicity. A number of scales have been developed. An example is a scale developed by Levitt, M, t al., J Mol Biol (1976) 104:59, which is listed in Hopp, T P, et al., Proc Natl Acad Sci USA (1981) 78:3824. Examples of “hydrophilic amino acids” are arginine, lysine, threonine, alanine, asparagine, and glutamine. Of particular interest are the hydrophilic amino acids aspartate, glutamate, and serine, and glycine. Examples of “hydrophobic amino acids” are tryptophan, tyrosine, phenylalanine, methionine, leucine, isoleucine, and valine.
A “fragment” is a truncated form of a native biologically active protein that retains at least a portion of the therapeutic and/or biological activity. A “variant” is a protein with sequence homology to the native biologically active protein that retains at least a portion of the therapeutic and/or biological activity of the biologically active protein. For example, a variant protein may share at least 70%, 75%, 80%, 85%°, 90%, 95%, 96%, 97%, 98% or 99% amino acid sequence identity with the reference biologically active protein. As used herein, the term “biologically active protein moiety” includes proteins modified deliberately, as for example, by site directed mutagenesis, insertions, or accidentally through mutations.
A “host cell” includes an individual cell or cell culture which can be or has been a recipient for the subject vectors. Host cells include progeny of a single host cell. The progeny may not necessarily be completely identical (in morphology or in genomic of total DNA complement) to the original parent cell due to natural, accidental, or deliberate mutation. A host cell includes cells transfected in vivo with a vector of this invention.
“Isolated,” when used to describe the various polypeptides disclosed herein, means polypeptide that has been identified and separated and/or recovered from a component of its natural environment. Contaminant components of its natural environment are materials that would typically interfere with diagnostic or therapeutic uses for the polypeptide, and may include enzymes, hormones, and other proteinaccous or non-proteinaceous solutes. As is apparent to those of skill in the art, a non-naturally occurring polynucleotide, peptide, polypeptide, protein, antibody, or fragments thereof, does not require “isolation” to distinguish it from its naturally occurring counterpart. In addition, a “concentrated”, “separated” or “diluted” polynucleotide, peptide, polypeptide, protein, antibody, or fragments thereof, is distinguishable from its naturally occurring counterpart in that the concentration or number of molecules per volume is generally greater than that of its naturally occurring counterpart. In general, a polypeptide made by recombinant means and expressed in a host cell is considered to be “isolated.”
An “isolated” polynucleotide or polypeptide-encoding nucleic acid or other polypeptide-encoding nucleic acid is a nucleic acid molecule that is identified and separated from at least one contaminant nucleic acid molecule with which it is ordinarily associated in the natural source of the polypeptide-encoding nucleic acid. An isolated polypeptide-encoding nucleic acid molecule is other than in the form or setting in which it is found in nature. Isolated polypeptide-encoding nucleic acid molecules therefore are distinguished from the specific polypeptide-encoding nucleic acid molecule as it exists in natural cells. However, an isolated polypeptide-encoding nucleic acid molecule includes polypeptide-encoding nucleic acid molecules contained in cells that ordinarily express the polypeptide where, for example, the nucleic acid molecule is in a chromosomal or extra-chromosomal location different from that of natural cells.
A “chimeric” protein contains at least one fusion polypeptide comprising regions in a different position in the sequence than that which occurs in nature. The regions may normally exist in separate proteins and are brought together in the fusion polypeptide: or they may normally exist in the same protein but are placed in a new arrangement in the fusion polypeptide. A chimeric protein may be created, for example, by chemical synthesis, or by creating and translating a polynucleotide in which the peptide regions are encoded in the desired relationship.
“Conjugated”, “linked,” “fused,” and “fusion” are used interchangeably herein. These terms refer to the joining together of two more chemical elements or components, by whatever means including chemical conjugation or recombinant means. For example, a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence. Generally, “operably linked” means that the DNA sequences being linked are contiguous, and in reading phase or in-frame. An “in-frame fusion” refers to the joining of two or more open reading frames (ORFs) to form a continuous longer ORF, in a manner that maintains the correct reading frame of the original ORFs. Thus, the resulting recombinant fusion protein is a single protein containing two ore more segments that correspond to polypeptides encoded by the original ORFs (which segments are not normally so joined in nature).
In the context of polypeptides, a “linear sequence” or a “sequence” is an order of amino acids in a polypeptide in an amino to carboxyl terminus direction in which residues that neighbor each other in the sequence are contiguous in the primary structure of the polypeptide. A “partial sequence” is a linear sequence of part of a polypeptide that is known to comprise additional residues in one or both directions.
“Heterologous” means derived from a genotypically distinct entity from the rest of the entity to which it is being compared. For example, a glycine rich sequence removed from its native coding sequence and operatively linked to a coding sequence other than the native sequence is a heterologous glycine rich sequence. The term “heterologous” as applied to a polynucleotide, a polypeptide, means that the polynucleotide or polypeptide is derived from a genotypically distinct entity from that of the rest of the entity to which it is being compared.
The terms “polynucleotides”, “nucleic acids”, “nucleotides” and “oligonucleotides” are used interchangeably. They refer to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or analogs thereof. Polynucleotides may have any three-dimensional structure, and may perform any function, known or unknown. The following are non-limiting examples of polynucleotides: coding or non-coding regions of a gene or gene fragment, loci (locus) defined from linkage analysis, exons, introns, messenger RNA (mRNA), transfer RNA, ribosomal RNA, ribozymes, cDNA, recombinant polynucleotides, branched polynucleotides, plasmids, vectors, isolated DNA of any sequence, isolated RNA of any sequence, nucleic acid probes, and primers. A polynucleotide may comprise modified nucleotides, such as methylated nucleotides and nucleotide analogs. If present, modifications to the nucleotide structure may be imparted before or after assembly of the polymer. The sequence of nucleotides may be interrupted by non-nucleotide components. A polynucleotide may be further modified after polymerization, such as by conjugation with a labeling component.
The term “complement of a polynucleotide” denotes a polynucleotide molecule having a complementary base sequence and reverse orientation as compared to a reference sequence, such that it could hybridize with a reference sequence with complete fidelity.
“Recombinant” as applied to a polynucleotide means that the polynucleotide is the product of various combinations of in vitro cloning, restriction and/or ligation steps, and other procedures that result in a construct that can potentially be expressed in a host cell.
The terms “gene” or “gene fragment” are used interchangeably herein. They refer to a polynucleotide containing at least one open reading frame that is capable of encoding a particular protein after being transcribed and translated. A gene or gene fragment may be genomic or cDNA, as long as the polynucleotide contains at least one open reading frame, which may cover the entire coding region or a segment thereof. A “fusion gene” is a gene composed of at least two heterologous polynucleotides that are linked together.
“Homology” or “homologous” refers to sequence similarity or interchangeability between two or more polynucleotide sequences or two or more polypeptide sequences. When using a program such as BestFit to determine sequence identity, similarity or homology between two different amino acid sequences, the default settings may be used, or an appropriate scoring matrix, such as blosum45 or blosum80, may be selected to optimize identity, similarity or homology scores. Preferably, polynucleotides that are homologous are those which hybridize under stringent conditions as defined herein and have at least 70%, preferably at least 80%, more preferably at least 90%, more preferably 95%, more preferably 97%, more preferably 98%, and even more preferably 99% sequence identity to those sequences.
The terms “stringent conditions” or “stringent hybridization conditions” includes reference to conditions under which a polynucleotide will hybridize to its target sequence, to a detectably greater degree than other sequences (e.g., at least 2-fold over background). Generally, stringency of hybridization is expressed, in part, with reference to the temperature and salt concentration under which the wash step is carried out. Typically, stringent conditions will be those in which the salt concentration is less than about 1.5 M Na ion, typically about 0.01 to 1.0 M Na ion concentration (or other salts) at pH 7.0 to 8.3 and the temperature is at least about 30° C. for short polynucleotides (e.g., 10 to 50 nucleotides) and at least about 60° C. for long polynucleotides (e.g., greater than 50 nucleotides)—for example, “stringent conditions” can include hybridization in 50% formamide, 1 M NaCl, 1% SDS at 37° C., and three washes for 15 min each in 0.1×SSC/1% SDS at 60 to 65° C. Alternatively, temperatures of about 65° C., 60° C., 55° C., or 42° C. may be used. SSC concentration may be varied from about 0.1 to 2×SSC, with SDS being present at about 0.1%. Such wash temperatures are typically selected to be about 5° C. to 20° C. lower than the thermal melting point © for the specific sequence at a defined ionic strength and pH. The Tm is the temperature (under defined ionic strength and pH) at which 50% of the target sequence hybridizes to a perfectly matched probe. An equation for calculating Tm and conditions for nucleic acid hybridization are well known and can be found in Sambrook, J. et al. (1989) Molecular Cloning: A Laboratory Manual, 2nd ed., vol. 1-3, Cold Spring Harbor Press, Plainview N.Y.; specifically see volume 2 and chapter 9. Typically, blocking reagents are used to block non-specific hybridization. Such blocking reagents include, for instance, sheared and denatured salmon sperm DNA at about 100-200 g/ml. Organic solvent, such as formamide at a concentration of about 35-50% v/v, may also be used under particular circumstances, such as for RNA:DNA hybridizations. Useful variations on these wash conditions will be readily apparent to those of ordinary skill in the art.
The terms “percent identity” and “% identity,” as applied to polynucleotide sequences, refer to the percentage of residue matches between at least two polynucleotide sequences aligned using a standardized algorithm. Such an algorithm may insert, in a standardized and reproducible way, gaps in the sequences being compared in order to optimize alignment between two sequences, and therefore achieve a more meaningful comparison of the two sequences. Percent identity may be measured over the length of an entire defined polynucleotide sequence, for example, as defined by a particular SEQ ID number, or may be measured over a shorter length, for example, over the length of a fragment taken from a larger, defined polynucleotide sequence, for instance, a fragment of at least 45, at least 60, at least 90, at least 120, at least 150, at least 210 or at least 450 contiguous residues. Such lengths are exemplary only, and it is understood that any fragment length supported by the sequences shown herein, in the tables, figures or Sequence Listing, may be used to describe a length over which percentage identity may be measured.
“Percent (%) amino acid sequence identity,” with respect to the polypeptide sequences identified herein, is defined as the percentage of amino acid residues in a query sequence that are identical with the amino acid residues of a second, reference polypeptide sequence or a portion thereof, after aligning the sequences and introducing gaps, if necessary, to achieve the maximum percent sequence identity, and not considering any conservative substitutions as part of the sequence identity. Alignment for purposes of determining percent amino acid sequence identity can be achieved in various ways that are within the skill in the art, for instance, using publicly available computer software such as BLAST, BLAST-2, ALIGN or Megalign (DNASTAR) software. Those skilled in the art can determine appropriate parameters for measuring alignment, including any algorithms needed to achieve maximal alignment over the full length of the sequences being compared. Percent identity may be measured over the length of an entire defined polypeptide sequence, for example, as defined by a particular SEQ ID number, or may be measured over a shorter length, for example, over the length of a fragment taken from a larger, defined polypeptide sequence, for instance, a fragment of at least 15, at least 20, at least 30, at least 40, at least 50, at least 70 or at least 150 contiguous residues. Such lengths are exemplary only, and it is understood that any fragment length supported by the sequences shown herein, in the tables, figures or Sequence Listing, may be used to describe a length over which percentage identity may be measured.
The term “non-repetitiveness” as used herein in the context of a polypeptide refers to a lack or limited degree of internal homology in a peptide or polypeptide sequence. The term “substantially non-repetitive” can mean, for example, that there are few or no instances of four contiguous amino acids in the sequence that are identical amino acid types or that the polypeptide has a subsequence score (defined infra) of 10 or less or that there isn't a pattern in the order, from N- to C-terminus, of the sequence motifs that constitute the polypeptide sequence. The term “repetitiveness” as used herein in the context of a polypeptide refers to the degree of internal homology in a peptide or polypeptide sequence. In contrast, a “repetitive” sequence may contain multiple identical copies of short amino acid sequences. For instance, a polypeptide sequence of interest may be divided into n-mer sequences and the number of identical sequences can be counted. Highly repetitive sequences contain a large fraction of identical sequences while non-repetitive sequences contain few identical sequences. In the context of a polypeptide, a sequence can contain multiple copies of shorter sequences of defined or variable length, or motifs, in which the motifs themselves have non-repetitive sequences, rendering the full-length polypeptide substantially non-repetitive. The length of polypeptide within which the non-repetitiveness is measured can vary from 3 amino acids to about 200 amino acids, about from 6 to about 50 amino acids, or from about 9 to about 14 amino acids. “Repetitiveness” used in the context of polynucleotide sequences refers to the degree of internal homology in the sequence such as, for example, the frequency of identical nucleotide sequences of a given length. Repetitiveness can, for example, be measured by analyzing the frequency of identical sequences.
A “vector” is a nucleic acid molecule, preferably self-replicating in an appropriate host, which transfers an inserted nucleic acid molecule into and/or between host cells. The term includes vectors that function primarily for insertion of DNA or RNA into a cell, replication of vectors that function primarily for the replication of DNA or RNA, and expression vectors that function for transcription and/or translation of the DNA or RNA. Also included are vectors that provide more than one of the above functions. An “expression vector” is a polynucleotide which, when introduced into an appropriate host cell, can be transcribed and translated into a polypeptide(s). An “expression system” usually connotes a suitable host cell comprised of an expression vector that can function to yield a desired expression product.
“Serum degradation resistance,” as applied to a polypeptide, refers to the ability of the polypeptides to withstand degradation in blood or components thereof, which typically involves proteases in the serum or plasma. The serum degradation resistance can be measured by combining the protein with human (or mouse, rat, monkey, as appropriate) serum or plasma, typically for a range of days (e.g. 0.25, 0.5, 1, 2, 4, 8, 16 days), typically at about 37° C. The samples for these time points can be run on a Western blot assay and the protein is detected with an antibody. The antibody can be to a tag in the protein. If the protein shows a single band on the western, where the protein's size is identical to that of the injected protein, then no degradation has occurred. In this exemplary method, the time point where 50% of the protein is degraded, as judged by Western blots or equivalent techniques, is the serum degradation half-life or “serum half-life” of the protein.
The term “t1/2” as used herein means the terminal half-life calculated as ln(2)/Kel·Kel, is the terminal elimination rate constant calculated by linear regression of the terminal linear portion of the log concentration vs. time curve. Half-life typically refers to the time required for half the quantity of an administered substance deposited in a living organism to be metabolized or eliminated by normal biological processes. The terms “t1/2”, “terminal half-life”, “elimination half-life” and “circulating half-life” are used interchangeably herein.
“Apparent Molecular Weight Factor” or “Apparent Molecular Weight” are related terms referring to a measure of the relative increase or decrease in apparent molecular weight exhibited by a particular amino acid sequence. The Apparent Molecular Weight is determined using size exclusion chromatography (SEC) and similar methods compared to globular protein standards and is measured in “apparent kD” units. The Apparent Molecular Weight Factor is the ratio between the Apparent Molecular Weight and the actual molecular weight; the latter predicted by adding, based on amino acid composition, the calculated molecular weight of each type of amino acid in the composition.
The “hydrodynamic radius” or “Stokes radius” is the effective radius (Rh in nm) of a molecule in a solution measured by assuming that it is a body moving through the solution and resisted by the solution's viscosity. In the embodiments of the invention, the hydrodynamic radius measurements of the XTEN fusion proteins correlate with the ‘Apparent Molecular Weight Factor’, which is a more intuitive measure. The “hydrodynamic radius” of a protein affects its rate of diffusion in aqueous solution as well as its ability to migrate in gels of macromolecules. The hydrodynamic radius of a protein is determined by its molecular weight as well as by its structure, including shape and compactness. Methods for determining the hydrodynamic radius are well known in the art, such as by the use of size exclusion chromatography (SEC), as described in U.S. Pat. Nos. 6,406,632 and 7,294,513. Most proteins have globular structure, which is the most compact three-dimensional structure a protein can have with the smallest hydrodynamic radius. Some proteins adopt a random and open, unstructured, or ‘linear’ conformation and as a result have a much larger hydrodynamic radius compared to typical globular proteins of similar molecular weight.
“Physiological conditions” refer to a set of conditions in a living host as well as in vitro conditions, including temperature, salt concentration, pH, that mimic those conditions of a living subject. A host of physiologically relevant conditions for use in in vitro assays have been established. Generally, a physiological buffer contains a physiological concentration of salt and is adjusted to a neutral pH ranging from about 6.5 to about 7.8, and preferably from about 7.0 to about 7.5. A variety of physiological buffers is listed in Sambrook et al. (1989). Physiologically relevant temperature ranges from about 25° C. to about 38° C., and preferably from about 35° C. to about 37° C.
A “reactive group” is a chemical structure that can be coupled to a second reactive group. Examples for reactive groups are amino groups, carboxyl groups, sulfhydryl groups, hydroxyl groups, aldehyde groups, azide groups. Some reactive groups can be activated to facilitate coupling with a second reactive group. Examples for activation are the reaction of a carboxyl group with carbodiimide, the conversion of a carboxyl group into an activated ester, or the conversion of a carboxyl group into an azide function.
“Controlled release agent”, “slow release agent”, “depot formulation” or “sustained release agent” are used interchangeably to refer to an agent capable of extending the duration of release of a polypeptide of the invention relative to the duration of release when the polypeptide is administered in the absence of agent. Different embodiments of the present invention may have different release rates, resulting in different therapeutic amounts.
The terms “antigen”, “target antigen” or “immunogen” are used interchangeably herein to refer to the structure or binding determinant that an antibody fragment or an antibody fragment-based therapeutic binds to or has specificity against.
The term “payload” as used herein refers to a protein or peptide sequence that has biological or therapeutic activity; the counterpart to the pharmacophore of small molecules. Examples of payloads include, but are not limited to, cytokines, enzymes, hormones and blood and growth factors. Payloads can further comprise genetically fused or chemically conjugated moieties such as chemotherapeutic agents, antiviral compounds, toxins, or contrast agents. These conjugated moieties can be joined to the rest of the polypeptide via a linker which may be cleavable or non-cleavable.
The term “antagonist”, as used herein, includes any molecule that partially or fully blocks, inhibits, or neutralizes a biological activity of a native polypeptide disclosed herein. Methods for identifying antagonists of a polypeptide may comprise contacting a native polypeptide with a candidate antagonist molecule and measuring a detectable change in one or more biological activities normally associated with the native polypeptide. In the context of the present invention, antagonists may include proteins, nucleic acids, carbohydrates, antibodies or any other molecules that decrease the effect of a biologically active protein.
The term “agonist” is used in the broadest sense and includes any molecule that mimics a biological activity of a native polypeptide disclosed herein. Suitable agonist molecules specifically include agonist antibodies or antibody fragments, fragments or amino acid sequence variants of native polypeptides, peptides, small organic molecules, etc. Methods for identifying agonists of a native polypeptide may comprise contacting a native polypeptide with a candidate agonist molecule and measuring a detectable change in one or more biological activities normally associated with the native polypeptide.
“Activity” for the purposes herein refers to an action or effect of a component of a fusion protein consistent with that of the corresponding native biologically active protein, wherein “biological activity” refers to an in vitro or in vivo biological function or effect, including but not limited to receptor binding, antagonist activity, agonist activity, or a cellular or physiologic response.
As used herein, “treatment” or “treating,” or “palliating” or “ameliorating” is used interchangeably herein. These terms refer to an approach for obtaining beneficial or desired results including but not limited to a therapeutic benefit and/or a prophylactic benefit. By therapeutic benefit is meant eradication or amelioration of the underlying disorder being treated. Also, a therapeutic benefit is achieved with the eradication or amelioration of one or more of the physiological symptoms associated with the underlying disorder such that an improvement is observed in the subject, notwithstanding that the subject may still be afflicted with the underlying disorder. For prophylactic benefit, the compositions may be administered to a subject at risk of developing a particular disease, or to a subject reporting one or more of the physiological symptoms of a disease, even though a diagnosis of this disease may not have been made.
A “therapeutic effect”, as used herein, refers to a physiologic effect, including but not limited to the cure, mitigation, amelioration, or prevention of disease in humans or other animals, or to otherwise enhance physical or mental wellbeing of humans or animals, caused by a fusion polypeptide of the invention other than the ability to induce the production of an antibody against an antigenic epitope possessed by the biologically active protein. Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein.
The terms “therapeutically effective amount” and “therapeutically effective dose”, as used herein, refers to an amount of a biologically active protein, either alone or as a part of a fusion protein composition, that is capable of having any detectable, beneficial effect on any symptom, aspect, measured parameter or characteristics of a disease state or condition when administered in one or repeated doses to a subject. Such effect need not be absolute to be beneficial.
The term “therapeutically effective dose regimen”, as used herein, refers to a schedule for consecutively administered doses of a biologically active protein, either alone or as a part of a fusion protein composition, wherein the doses are given in therapeutically effective amounts to result in sustained beneficial effect on any symptom, aspect, measured parameter or characteristics of a disease state or condition.
I). General Techniques
The practice of the present invention employs, unless otherwise indicated, conventional techniques of immunology, biochemistry, chemistry, molecular biology, microbiology, cell biology, genomics and recombinant DNA, which are within the skill of the art. See Sambrook, J. et al., “Molecular Cloning: A Laboratory Manual,” 3rd edition, Cold Spring Harbor Laboratory Press, 2001; “Current protocols in molecular biology”, F. M. Ausubel, et al. eds., 1987, the series “Methods in Enzymology,” Academic Press, San Diego, Calif.: “PCR 2: a practical approach”, M. J. MacPherson, B. D. Hames and G. R. Taylor eds., Oxford University Press, 1995; “Antibodies, a laboratory manual” Harlow, E. and Lane, D. eds., Cold Spring Harbor Laboratory, 1988: “Goodman & Gilman's The Pharmacological Basis of Therapeutics.” 11th Edition, McGraw-Hill, 2005; and Freshney, R. I., “Culture of Animal Cells: A Manual of Basic Technique,” 4th edition, John Wiley & Sons, Somerset, N.J. 2000, the contents of which are incorporated in their entirety herein by reference.
II). Extended Recombinant Polypeptides
The present invention provides compositions comprising extended recombinant polypeptides (“XTEN” or “XTENs”). In some embodiments, XTEN are generally extended length polypeptides with non-naturally occurring, substantially non-repetitive sequences that are composed mainly of small hydrophilic amino acids, with the sequence having a low degree or no secondary or tertiary structure under physiologic conditions.
In one aspect of the invention, XTEN polypeptide compositions are disclosed that are useful as fusion partners that can be linked to biologically active proteins (“BP”), resulting in a BPXTEN fusion proteins (e.g., monomeric fusions). XTENs can have utility as fusion protein partners in that they can confer certain chemical and pharmaceutical properties when linked to a biologically active protein to a create a fusion protein. Such desirable properties include but are not limited to enhanced pharmacokinetic parameters and solubility characteristics, amongst other properties described below. Such fusion protein compositions may have utility to treat certain diseases, disorders or conditions, as described herein. As used herein, “XTEN” specifically excludes antibodies or antibody fragments such as single-chain antibodies, Fc fragments of a light chain or a heavy chain.
In some embodiments, XTEN are long polypeptides having greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 residues when used as a single sequence, and cumulatively have greater than about 400 to about 3000 amino acid residues when more than one XTEN unit is used in a single fusion protein or conjugate. In other cases, where an increase in half-life of the fusion protein is not needed but where an increase in solubility or other physico/chemical property for the biologically active protein fusion partner is desired, an XTEN sequence shorter than 100 amino acid residues, such as about 96, or about 84, or about 72, or about 60, or about 48, or about 36 amino acid residues may be incorporated into a fusion protein composition with the BP to effect the property.
The selection criteria for the XTEN to be linked to the biologically active proteins to create the inventive fusion proteins generally relate to attributes of physical/chemical properties and conformational structure of the XTEN that can be, in turn, used to confer enhanced pharmaceutical and pharmacokinetic properties to the fusion proteins. The XTEN of the present invention may exhibit one or more of the following advantageous properties: conformational flexibility, enhanced aqueous solubility, high degree of protease resistance, low immunogenicity, low binding to mammalian receptors, and increased hydrodynamic (or Stokes) radii; properties that can make them particularly useful as fusion protein partners. Non-limiting examples of the properties of the fusion proteins comprising BP that may be enhanced by XTEN include increases in the overall solubility and/or metabolic stability, reduced susceptibility to proteolysis, reduced immunogenicity, reduced rate of absorption when administered subcutaneously or intramuscularly, and enhanced pharmacokinetic properties such as terminal half-life and area under the curve (AUC), slower absorption after subcutaneous or intramuscular injection (compared to BP not linked to XTEN) such that the Cmax is lower, which may, in turn, result in reductions in adverse effects of the BP that, collectively, can result in an increased period of time that a fusion protein of a BPXTEN composition administered to a subject remains within a therapeutic window, compared to the corresponding BP component not linked to XTEN.
A variety of methods and assays are known in the art for determining the physical/chemical properties of proteins such as the fusion protein compositions comprising the inventive XTEN; properties such as secondary or tertiary structure, solubility, protein aggregation, melting properties, contamination and water content. Such methods include analytical centrifugation, EPR. HPLC-ion exchange, HPLC-size exclusion, HPLC-reverse phase, light scattering, capillary electrophoresis, circular dichroism, differential scanning calorimetry, fluorescence, HPLC-ion exchange, HPLC-size exclusion, IR, NMR, Raman spectroscopy, refractometry, and UV/Visible spectroscopy. Additional methods are disclosed in Amau et al. Prot Expr and Purif (2006) 48, 1-13. Application of these methods to the invention would be within the grasp of a person skilled in the art.
Typically, the XTEN component of the fusion proteins are designed to behave like denatured peptide sequences under physiological conditions, despite the extended length of the polymer. Denatured describes the state of a peptide in solution that is characterized by a large conformational freedom of the peptide backbone. Most peptides and proteins adopt a denatured conformation in the presence of high concentrations of denaturants or at elevated temperature. Peptides in denatured conformation have, for example, characteristic circular dichroism (CD) spectra and are characterized by a lack of long-range interactions as determined by NMR. “Denatured conformation” and “unstructured conformation” are used synonymously herein. In some cases, the invention provides XTEN sequences that, under physiologic conditions, can resemble denatured sequences largely devoid in secondary structure. In other cases, the XTEN sequences can be substantially devoid of secondary structure under physiologic conditions. “Largely devoid,” as used in this context, means that less than 50% of the XTEN amino acid residues of the XTEN sequence contribute to secondary structure as measured or determined by the means described herein. “Substantially devoid,” as used in this context, means that at least about 60%, or about 70%, or about 80%, or about 90%, or about 95%, or at least about 99% of the XTEN amino acid residues of the XTEN sequence do not contribute to secondary structure, as measured or determined by the means described herein.
A variety of methods have been established in the art to discern the presence or absence of secondary and tertiary structures in a given polypeptide. In particular, secondary structure can be measured spectrophotometrically, e.g., by circular dichroism spectroscopy in the “far-UV” spectral region (190-250 nm). Secondary structure elements, such as alpha-helix and beta-sheet, each give rise to a characteristic shape and magnitude of CD spectra. Secondary structure can also be predicted for a polypeptide sequence via certain computer programs or algorithms, such as the well-known Chou-Fasman algorithm (Chou, P. Y., et al. (1974) Biochemistry, 13: 222-45) and the Garnier-Osguthorpe-Robson (“GOR”) algorithm (Garnier J, Gibrat J F, Robson B. (1996), GOR method for predicting protein secondary structure from amino acid sequence. Methods Enzymol 266:540-553), as described in US Patent Application Publication No. 20030228309A1. For a given sequence, the algorithms can predict whether there exists some or no secondary structure at all, expressed as the total and/or percentage of residues of the sequence that form, for example, alpha-helices or beta-sheets or the percentage of residues of the sequence predicted to result in random coil formation (which lacks secondary structure).
In some cases, the XTEN sequences used in the inventive fusion protein compositions can have an alpha-helix percentage ranging from 0% to less than about 5% as determined by a Chou-Fasman algorithm. In other cases, the XTEN sequences of the fusion protein compositions can have a beta-sheet percentage ranging from 0% to less than about 5% as determined by a Chou-Fasman algorithm. In some cases, the XTEN sequences of the fusion protein compositions can have an alpha-helix percentage ranging from 0% to less than about 5% and a beta-sheet percentage ranging from 0% to less than about 5% as determined by a Chou-Fasman algorithm. In preferred embodiments, the XTEN sequences of the fusion protein compositions will have an alpha-helix percentage less than about 2% and a beta-sheet percentage less than about 2%. In other cases, the XTEN sequences of the fusion protein compositions can have a high degree of random coil percentage, as determined by a GOR algorithm. In some embodiments, an XTEN sequence can have at least about 80%, more preferably at least about 90%, more preferably at least about 91%, more preferably at least about 92%, more preferably at least about 93%, more preferably at least about 94%, more preferably at least about 95%, more preferably at least about 96%, more preferably at least about 97%, more preferably at least about 98%, and most preferably at least about 99% random coil, as determined by a GOR algorithm.
1. Non-Repetitive Sequences
XTEN sequences of the subject compositions can be substantially non-repetitive. In general, repetitive amino acid sequences have a tendency to aggregate or form higher order structures, as exemplified by natural repetitive sequences such as collagens and leucine zippers, or form contacts resulting in crystalline or pseudocrystaline structures. In contrast, the low tendency of non-repetitive sequences to aggregate enables the design of long-sequence XTENs with a relatively low frequency of charged amino acids that would be likely to aggregate if the sequences were otherwise repetitive. Typically, the BPXTEN fusion proteins comprise XTEN sequences of greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 residues, wherein the sequences are substantially non-repetitive. In one embodiment, the XTEN sequences can have greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 amino acid residues, in which no three contiguous amino acids in the sequence are identical amino acid types unless the amino acid is serine, in which case no more than three contiguous amino acids are serine residues. In the foregoing embodiment, the XTEN sequence would be substantially non-repetitive.
The degree of repetitiveness of a polypeptide or a gene can be measured by computer programs or algorithms or by other means known in the art. Repetitiveness in a polypeptide sequence can, for example, be assessed by determining the number of times shorter sequences of a given length occur within the polypeptide. For example, a polypeptide of 200 amino acid residues has 192 overlapping 9-amino acid sequences (or 9-mer “frames”) and 198 3-mer frames, but the number of unique 9-mer or 3-mer sequences will depend on the amount of repetitiveness within the sequence. A score can be generated (hereinafter “subsequence score”) that is reflective of the degree of repetitiveness of the subsequences in the overall polypeptide sequence. In the context of the present invention, “subsequence score” means the sum of occurrences of each unique 3-mer frame across a 200 consecutive amino acid sequence of the polypeptide divided by the absolute number of unique 3-mer subsequences within the 200 amino acid sequence. Examples of such subsequence scores derived from the first 200 amino acids of repetitive and non-repetitive polypeptides are presented in Example 73. In some embodiments, the present invention provides BPXTEN each comprising XTEN in which the XTEN can have a subsequence score less than 12, more preferably less than 10, more preferably less than 9, more preferably less than 8, more preferably less than 7, more preferably less than 6, and most preferably less than 5. In the embodiments hereinabove described in this paragraph, an XTEN with a subsequence score less than about 10 (i.e., 9, 8, 7, etc.) would be “substantially non-repetitive.”
The non-repetitive characteristic of XTEN can impart to fusion proteins with BP(s) a greater degree of solubility and less tendency to aggregate compared to polypeptides having repetitive sequences. These properties can facilitate the formulation of XTEN-comprising pharmaceutical preparations containing extremely high drug concentrations, in some cases exceeding 100 mg/ml.
Furthermore, the XTEN polypeptide sequences of the embodiments are designed to have a low degree of internal repetitiveness in order to reduce or substantially eliminate immunogenicity when administered to a mammal. Polypeptide sequences composed of short, repeated motifs largely limited to three amino acids, such as glycine, serine and glutamate, may result in relatively high antibody titers when administered to a mammal despite the absence of predicted T-cell epitopes in these sequences. This may be caused by the repetitive nature of polypeptides, as it has been shown that immunogens with repeated epitopes, including protein aggregates, cross-linked immunogens, and repetitive carbohydrates are highly immunogenic and can, for example, result in the cross-linking of B-cell receptors causing B-cell activation. (Johansson, J., et al. (2007) Vaccine, 25:1676-82. Yankai, Z., et al. (2006) Biochem Biophys Res Commun, 345:1365-71; Hsu, C. T., et al. (2000) Cancer Res, 60:3701-5); Bachmann M F, et al. Eur J Immunol. (1995) 25(12):3445-3451).
2. Exemplary Sequence Motifs
The present invention encompasses XTEN that can comprise multiple units of shorter sequences, or motifs, in which the amino acid sequences of the motifs are non-repetitive. In designing XTEN sequences, it was discovered that the non-repetitive criterion may be met despite the use of a “building block” approach using a library of sequence motifs that are multimerized to create the XTEN sequences. Thus, while an XTEN sequence may consist of multiple units of as few as four different types of sequence motifs, because the motifs themselves generally consist of non-repetitive amino acid sequences, the overall XTEN sequence is rendered substantially non-repetitive.
In one embodiment, XTEN can have a non-repetitive sequence of greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 residues, wherein at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 97%, or about 100% of the XTEN sequence consists of non-overlapping sequence motifs, wherein each of the motifs has about 9 to 36 amino acid residues. In other embodiments, at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 97%, or about 100% of the XTEN sequence consists of non-overlapping sequence motifs wherein each of the motifs has 9 to 14 amino acid residues. In still other embodiments, at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 97%, or about 100% of the XTEN sequence component consists of non-overlapping sequence motifs wherein each of the motifs has 12 amino acid residues. In these embodiments, it is preferred that the sequence motifs be composed mainly of small hydrophilic amino acids, such that the overall sequence has an unstructured, flexible characteristic. Examples of amino acids that can be included in XTEN, are, e.g., arginine, lysine, threonine, alanine, asparagine, glutamine, aspartate, glutamate, serine, and glycine. As a result of testing variables such as codon optimization, assembly polynucleotides encoding sequence motifs, expression of protein, charge distribution and solubility of expressed protein, and secondary and tertiary structure, it was discovered that XTEN compositions with enhanced characteristics mainly include glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P) residues wherein the sequences are designed to be substantially non-repetitive. In a preferred embodiment. XTEN sequences have predominately four to six types of amino acids selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) or proline (P) that are arranged in a substantially non-repetitive sequence that is greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 residues in length. In some embodiments, XTEN can have sequences of greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 residues, wherein at least about 80% of the sequence consists of non-overlapping sequence motifs wherein each of the motifs has 9 to 36 amino acid residues wherein each of the motifs consists of 4 to 6 types of amino acids selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein the content of any one amino acid type in the full-length XTEN does not exceed 30%. In other embodiments, at least about 90% of the XTEN sequence consists of non-overlapping sequence motifs wherein each of the motifs has 9 to 36 amino acid residues wherein the motifs consist of 4 to 6 types of amino acids selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein the content of any one amino acid type in the full-length XTEN does not exceed 30%. In other embodiments, at least about 90% of the XTEN sequence consists of non-overlapping sequence motifs wherein each of the motifs has 12 amino acid residues consisting of 4 to 6 types of amino acids selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein the content of any one amino acid type in the full-length XTEN does not exceed 30%. In yet other embodiments, at least about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99%, to about 100% of the XTEN sequence consists of non-overlapping sequence motifs wherein each of the motifs has 12 amino acid residues consisting of glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein in the content of any one amino acid type in the full-length XTEN does not exceed 30%.
In still other embodiments, XTENs comprise non-repetitive sequences of greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 amino acid residues wherein at least about 80%, or at least about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% of the sequence consists of non-overlapping sequence motifs of 9 to 14 amino acid residues wherein the motifs consist of 4 to 6 types of amino acids selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein the sequence of any two contiguous amino acid residues in any one motif is not repeated more than twice in the sequence motif. In other embodiments, at least about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% of an XTEN sequence consists of non-overlapping sequence motifs of 12 amino acid residues wherein the motifs consist of 4 to 6 types of amino acids selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein the sequence of any two contiguous amino acid residues in any one sequence motif is not repeated more than twice in the sequence motif. In other embodiments, at least about 90%, or about 91%& or about 92%, or about 93%, or about 94%, or about 95%& or about 96%, or about 97%, or about 98%, or about 99% of an XTEN sequence consists of non-overlapping sequence motifs of 12 amino acid residues wherein the motifs consist of glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein the sequence of any two contiguous amino acid residues in any one sequence motif is not repeated more than twice in the sequence motif. In yet other embodiments. XTENs consist of 12 amino acid sequence motifs wherein the amino acids are selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), and wherein the sequence of any two contiguous amino acid residues in any one sequence motif is not repeated more than twice in the sequence motif, and wherein the content of any one amino acid type in the full-length XTEN does not exceed 30%. In the foregoing embodiments hereinabove described in this paragraph, the XTEN sequences would be substantially non-repetitive.
In some cases, the invention provides compositions comprising a non-repetitive XTEN sequence of greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 residues, wherein at least about 80%, or at least about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% to about 100% of the sequence consists of multiple units of two or more non-overlapping sequence motifs selected from the amino acid sequences of Table 1. In some cases, the XTEN comprises non-overlapping sequence motifs in which about 80%, or at least about 90%, or about 91%, or about 92%, or about 93%, or about 94%& or about 95%, or about 96%, or about 97%, or about 98%, or about 99% to about 100% of the sequence consists of two or more non-overlapping sequences selected from a single motif family of Table 1, resulting in a “family” sequence in which the overall sequence remains substantially non-repetitive. Accordingly, in these embodiments, an XTEN sequence can comprise multiple units of non-overlapping sequence motifs of the AD motif family, or the AE motif family, or the AF motif family, or the AG motif family, or the AM motif family, or the AQ motif family, or the BC family, or the BD family of sequences of Table 1. In other cases, the XTEN comprises motif sequences from two or more of the motif families of Table 1.
In other cases, BPXTEN composition can comprise a non-repetitive XTEN sequence of greater than about 100 to about 3000 amino acid residues, preferably greater than 400 to about 3000 residues, wherein at least about 80%, or at least about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99% to about 100% of the sequence consists of non-overlapping 36 amino acid sequence motifs selected from one or more of the polypeptide sequences of Tables 12-15.
In those embodiments wherein the XTEN component of the BPXTEN fusion protein has less than 100% of its amino acids consisting of four to six amino acid selected from glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), or less than 100% of the sequence consisting of the sequence motifs of Tables 1 or the polypeptide sequences to Tables 12-15, or less than 100% sequence identity with an XTEN from Table 2, the other amino acid residues can be selected from any other of the 14 natural L-amino acids. The other amino acids may be interspersed throughout the XTEN sequence, may be located within or between the sequence motifs, or may be concentrated in one or more short stretches of the XTEN sequence. In such cases where the XTEN component of the BPXTEN comprises amino acids other than glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P), it is preferred that the amino acids not be hydrophobic residues and should not substantially confer secondary structure of the XTEN component. Thus, in a preferred embodiment of the foregoing, the XTEN component of the BPXTEN fusion protein comprising other amino acids in addition to glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P) would have a sequence with less than 5% of the residues contributing to alpha-helices and beta-sheets as measured by Chou-Fasman algorithm and would have at least 90% random coil formation as measured by GOR algorithm.
3. Length of Sequence
In a particular feature, the invention encompasses BPXTEN compositions comprising XTEN polypeptides with extended length sequences. The present invention makes use of the discovery that increasing the length of non-repetitive, unstructured polypeptides enhances the unstructured nature of the XTENs and the biological and pharmacokinetic properties of fusion proteins comprising the XTEN. As described more fully in the Examples, proportional increases in the length of the XTEN, even if created by a fixed repeat order of single family sequence motifs (e.g., the four AE motifs of Table 1), can result in a sequence with a higher percentage of random coil formation, as determined by GOR algorithm, compared to shorter XTEN lengths. In addition, it was discovered that increasing the length of the unstructured polypeptide fusion partner can, as described in the Examples, result in a fusion protein with a disproportional increase in terminal half-life compared to fusion proteins with unstructured polypeptide partners with shorter sequence lengths.
Non-limiting examples of XTEN contemplated for inclusion in the BPXTEN of the invention are presented in Table 2. Accordingly, the invention provides BPXTEN compositions wherein the XTEN sequence length of the fusion protein(s) is greater than about 100 to about 3000 amino acid residues, and in some cases is greater than 400 to about 3000 amino acid residues, wherein the XTEN confers enhanced pharmacokinetic properties on the BPXTEN in comparison to payloads not linked to XTEN. In some cases, the XTEN sequences of the BPXTEN compositions of the present invention can be about 100, or about 144, or about 288, or about 401, or about 500, or about 600, or about 700, or about 800, or about 900, or about 1000, or about 1500, or about 2000, or about 2500 or up to about 3000 amino acid residues in length. In other cases, the XTEN sequences can be about 100 to 150, about 150 to 250, about 250 to 400, 401 to about 500, about 500 to 900, about 900 to 1500, about 1500 to 2000, or about 2000 to about 3000 amino acid residues in length. In one embodiment, the BPXTEN can comprise an XTEN sequence wherein the sequence exhibits at least about 80% sequence identity, or alternatively 810%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a XTEN selected from Table 2. In some cases, the XTEN sequence is designed for optimized expression as the N-terminal component of the BPXTEN. In one embodiment of the foregoing, the XTEN sequence has at least 90% sequence identity to the sequence of AE912 or AM923. In another embodiment of the foregoing, the XTEN has the N-terminal residues described in Examples 14-17.
In other cases, the BPXTEN fusion protein can comprise a first and a second XTEN sequence, wherein the cumulative total of the residues in the XTEN sequences is greater than about 400 to about 3000 amino acid residues. In embodiments of the foregoing, the BPXTEN fusion protein can comprise a first and a second XTEN sequence wherein the sequences each exhibit at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to at least a first or additionally a second XTEN selected from Table 2. Examples where more than one XTEN is used in a BPXTEN composition include, but are not limited to constructs with an XTEN linked to both the N- and C-termini of at least one BP.
As described more fully below, the invention provides methods in which the BPXTEN is designed by selecting the length of the XTEN to confer a target half-life on a fusion protein administered to a subject. In general, longer XTEN lengths incorporated into the BPXTEN compositions result in longer half-life compared to shorter XTEN. However, in another embodiment, BPXTEN fusion proteins can be designed to comprise XTEN with a longer sequence length that is selected to confer slower rates of systemic absorption after subcutaneous or intramuscular administration to a subject. In such cases, the Cmax is reduced in comparison to a comparable dose of a BP not linked to XTEN, thereby contributing to the ability to keep the BPXTEN within the therapeutic window for the composition. Thus, the XTEN confers the property of a depot to the administered BPXTEN, in addition to the other physical/chemical properties described herein.
4. Net Charge
In other cases, the XTEN polypeptides can have an unstructured characteristic imparted by incorporation of amino acid residues with a net charge and/or reducing the proportion of hydrophobic amino acids in the XTEN sequence. The overall net charge and net charge density may be controlled by modifying the content of charged amino acids in the XTEN sequences. In some cases, the net charge density of the XTEN of the compositions may be above +0.1 or below −0.1 charges/residue. In other cases, the net charge of a XTEN can be about 0%, about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10% about 11/%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, or about 20% or more.
Since most tissues and surfaces in a human or animal have a net negative charge, the XTEN sequences can be designed to have a net negative charge to minimize non-specific interactions between the XTEN containing compositions and various surfaces such as blood vessels, healthy tissues, or various receptors. Not to be bound by a particular theory, the XTEN can adopt open conformations due to electrostatic repulsion between individual amino acids of the XTEN polypeptide that individually carry a high net negative charge and that are distributed across the sequence of the XTEN polypeptide. Such a distribution of net negative charge in the extended sequence lengths of XTEN can lead to an unstructured conformation that, in turn, can result in an effective increase in hydrodynamic radius. Accordingly, in one embodiment the invention provides XTEN in which the XTEN sequences contain about 8, 10, 15, 20, 25, or even about 30% glutamic acid. The XTEN of the compositions of the present invention generally have no or a low content of positively charged amino acids. In some cases the XTEN may have less than about 10% amino acid residues with a positive charge, or less than about 7%, or less than about 5%, or less than about 2% amino acid residues with a positive charge. However, the invention contemplates constructs where a limited number of amino acids with a positive charge, such as lysine, may be incorporated into XTEN to permit conjugation between the epsilon amine of the lysine and a reactive group on a peptide, a linker bridge, or a reactive group on a drug or small molecule to be conjugated to the XTEN backbone. In the foregoing, a fusion proteins can be constructed that comprises XTEN, a biologically active protein, plus a chemotherapeutic agent useful in the treatment of metabolic diseases or disorders, wherein the maximum number of molecules of the agent incorporated into the XTEN component is determined by the numbers of lysines or other amino acids with reactive side chains (e.g., cysteine) incorporated into the XTEN.
In some cases, an XTEN sequence may comprise charged residues separated by other residues such as serine or glycine, which may lead to better expression or purification behavior. Based on the net charge, XTENs of the subject compositions may have an isoelectric point (pI) of 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, or even 6.5. In preferred embodiments, the XTEN will have an isoelectric point between 1.5 and 4.5. In these embodiments, the XTEN incorporated into the BPXTEN fusion protein compositions of the present invention would carry a net negative charge under physiologic conditions that may contribute to the unstructured conformation and reduced binding of the XTEN component to mammalian proteins and tissues.
As hydrophobic amino acids can impart structure to a polypeptide, the invention provides that the content of hydrophobic amino acids in the XTEN will typically be less than 5%, or less than 2%, or less than 1% hydrophobic amino acid content. In one embodiment, the amino acid content of methionine and tryptophan in the XTEN component of a BPXTEN fusion protein is typically less than 5%, or less than 2%, and most preferably less than 1%. In another embodiment, the XTEN will have a sequence that has less than 10% amino acid residues with a positive charge, or less than about 7%, or less that about 5%, or less than about 2% amino acid residues with a positive charge, the sum of methionine and tryptophan residues will be less than 2%, and the sum of asparagine and glutamine residues will be less than 10% of the total XTEN sequence.
5. Low Immunogenicity
In another aspect, the invention provides compositions in which the XTEN sequences have a low degree of immunogenicity or are substantially non-immunogenic. Several factors can contribute to the low immunogenicity of XTEN, e.g., the non-repetitive sequence, the unstructured conformation, the high degree of solubility, the low degree or lack of self-aggregation, the low degree or lack of proteolytic sites within the sequence, and the low degree or lack of epitopes in the XTEN sequence.
Conformational epitopes are formed by regions of the protein surface that are composed of multiple discontinuous amino acid sequences of the protein antigen. The precise folding of the protein brings these sequences into a well-defined, stable spatial configurations, or epitopes, that can be recognized as “foreign” by the host humoral immune system, resulting in the production of antibodies to the protein or triggering a cell-mediated immune response. In the latter case, the immune response to a protein in an individual is heavily influenced by T-cell epitope recognition that is a function of the peptide binding specificity of that individual's HLA-DR allotype. Engagement of a MHC Class II peptide complex by a cognate T-cell receptor on the surface of the T-cell, together with the cross-binding of certain other co-receptors such as the CD4 molecule, can induce an activated state within the T-cell. Activation leads to the release of cytokines further activating other lymphocytes such as B cells to produce antibodies or activating T killer cells as a full cellular immune response.
The ability of a peptide to bind a given MHC Class II molecule for presentation on the surface of an APC (antigen presenting cell) is dependent on a number of factors; most notably its primary sequence. In one embodiment, a lower degree of immunogenicity may be achieved by designing XTEN sequences that resist antigen processing in antigen presenting cells, and/or choosing sequences that do not bind MHC receptors well. The invention provides BPXTEN fusion proteins with substantially non-repetitive XTEN polypeptides designed to reduce binding with MHC II receptors, as well as avoiding formation of epitopes for T-cell receptor or antibody binding, resulting in a low degree of immunogenicity. Avoidance of immunogenicity is, in part, a direct result of the conformational flexibility of XTEN sequences, i.e., the lack of secondary structure due to the selection and order of amino acid residues. For example, of particular interest are sequences having a low tendency to adapt compactly folded conformations in aqueous solution or under physiologic conditions that could result in conformational epitopes. The administration of fusion proteins comprising XTEN, using conventional therapeutic practices and dosing, would generally not result in the formation of neutralizing antibodies to the XTEN sequence, and may also reduce the immunogenicity of the BP fusion partner in the BPXTEN compositions.
In one embodiment, the XTEN sequences utilized in the subject fusion proteins can be substantially free of epitopes recognized by human T cells. The elimination of such epitopes for the purpose of generating less immunogenic proteins has been disclosed previously, see for example WO 98/52976, WO 02/079232, and WO 00/3317 which are incorporated by reference herein. Assays for human T cell epitopes have been described (Stickler, M., et al. (2003) J Immunol Methods, 281: 95-108). Of particular interest are peptide sequences that can be oligomerized without generating T cell epitopes or non-human sequences. This can be achieved by testing direct repeats of these sequences for the presence of T-cell epitopes and for the occurrence of 6 to 15-mer and, in particular, 9-mer sequences that are not human, and then altering the design of the XTEN sequence to eliminate or disrupt the epitope sequence. In some cases, the XTEN sequences are substantially non-immunogenic by the restriction of the numbers of epitopes of the XTEN predicted to bind MHC receptors. With a reduction in the numbers of epitopes capable of binding to MHC receptors, there is a concomitant reduction in the potential for T cell activation as well as T cell helper function, reduced B cell activation or upregulation and reduced antibody production. The low degree of predicted T-cell epitopes can be determined by epitope prediction algorithms such as, e.g., TEPITOPE (Sturniolo, T., et al. (1999) Nat Biotechnol, 17: 555-61), as shown in Example 74. The TEPITOPE score of a given peptide frame within a protein is the log of the Kd (dissociation constant, affinity, off-rate) of the binding of that peptide frame to multiple of the most common human MHC alleles, as disclosed in Sturniolo, T. et al. (1999) Nature Biotechnology 17:555). The score ranges over at least 20 logs, from about 10 to about −10 (corresponding to binding constraints of 10e10 Kd to 10e−10 Kd), and can be reduced by avoiding hydrophobic amino acids that can serve as anchor residues during peptide display on MHC, such as M, I, L, V, F. In some embodiments, an XTEN component incorporated into a BPXTEN does not have a predicted T-cell epitope at a TEPITOPE score of about −5 or greater, or −6 or greater, or −7 or greater, or −8 or greater, or at a TEPITOPE score of −9 or greater. As used herein, a score of “−9 or greater” would encompass TEPITOPE scores of 10 to −9, inclusive, but would not encompass a score of −10, as −10 is less than −9.
In another embodiment, the inventive XTEN sequences, including those incorporated into the subject BPXTEN fusion proteins, can be rendered substantially non-immunogenic by the restriction of known proteolytic sites from the sequence of the XTEN, reducing the processing of XTEN into small peptides that can bind to MHC II receptors. In another embodiment, the XTEN sequence can be rendered substantially non-immunogenic by the use a sequence that is substantially devoid of secondary structure, conferring resistance to many proteases due to the high entropy of the structure. Accordingly, the reduced TEPITOPE score and elimination of known proteolytic sites from the XTEN may render the XTEN compositions, including the XTEN of the BPXTEN fusion protein compositions, substantially unable to be bound by mammalian receptors, including those of the immune system. In one embodiment, an XTEN of a BPXTEN fusion protein can have >100 nM Kd binding to a mammalian receptor, or greater than 500 nM Kd, or greater than 1 μM Kd towards a mammalian cell surface or circulating polypeptide receptor.
Additionally, the non-repetitive sequence and corresponding lack of epitopes of XTEN can limit the ability of B cells to bind to or be activated by XTEN. A repetitive sequence is recognized and can form multivalent contacts with even a few B cells and, as a consequence of the cross-linking of multiple T-cell independent receptors, can stimulate B cell proliferation and antibody production. In contrast, while a XTEN can make contacts with many different B cells over its extended sequence, each individual B cell may only make one or a small number of contacts with an individual XTEN due to the lack of repetitiveness of the sequence. As a result, XTENs typically may have a much lower tendency to stimulate proliferation of B cells and thus an immune response. In one embodiment, the BPXTEN may have reduced immunogenicity as compared to the corresponding BP that is not fused. In one embodiment, the administration of up to three parenteral doses of a BPXTEN to a mammal may result in detectable anti-BPXTEN IgG at a serum dilution of 1:100 but not at a dilution of 1:1000. In another embodiment, the administration of up to three parenteral doses of an BPXTEN to a mammal may result in detectable anti-BP IgG at a serum dilution of 1:100 but not at a dilution of 1:1000. In another embodiment, the administration of up to three parenteral doses of an BPXTEN to a mammal may result in detectable anti-XTEN IgG at a serum dilution of 1:100 but not at a dilution of 1:1000. In the foregoing embodiments, the mammal can be a mouse, a rat, a rabbit, or a cynomolgus monkey.
An additional feature of XTENs with non-repetitive sequences relative to sequences with a high degree of repetitiveness can be that non-repetitive XTENs form weaker contacts with antibodies. Antibodies are multivalent molecules. For instance, IgGs have two identical binding sites and IgMs contain 10 identical binding sites. Thus antibodies against repetitive sequences can form multivalent contacts with such repetitive sequences with high avidity, which can affect the potency and/or elimination of such repetitive sequences. In contrast, antibodies against non-repetitive XTENs may yield monovalent interactions, resulting in less likelihood of immune clearance such that the BPXTEN compositions can remain in circulation for an increased period of time.
6. Increased Hydrodynamic Radius
In another aspect, the present invention provides XTEN in which the XTEN polypeptides can have a high hydrodynamic radius that confers a corresponding increased Apparent Molecular Weight to the BPXTEN fusion protein incorporating the XTEN. As detailed in Example 19, the linking of XTEN to BP sequences can result in BPXTEN compositions that can have increased hydrodynamic radii, increased Apparent Molecular Weight, and increased Apparent Molecular Weight Factor compared to a BP not linked to an XTEN. For example, in therapeutic applications in which prolonged half-life is desired, compositions in which a XTEN with a high hydrodynamic radius is incorporated into a fusion protein comprising one or more BP can effectively enlarge the hydrodynamic radius of the composition beyond the glomerular pore size of approximately 3-5 nm (corresponding to an apparent molecular weight of about 70 kDA) (Caliceti. 2003. Pharmacokinctic and biodistribution properties of poly(ethylene glycol)-protein conjugates. Adv Drug Deliv Rev 55:1261-1277), resulting in reduced renal clearance of circulating proteins. The hydrodynamic radius of a protein is determined by its molecular weight as well as by its structure, including shape and compactness. Not to be bound by a particular theory, the XTEN can adopt open conformations due to electrostatic repulsion between individual charges of the peptide or the inherent flexibility imparted by the particular amino acids in the sequence that lack potential to confer secondary structure. The open, extended and unstructured conformation of the XTEN polypeptide can have a greater proportional hydrodynamic radius compared to polypeptides of a comparable sequence length and/or molecular weight that have secondary and/or tertiary structure, such as typical globular proteins. Methods for determining the hydrodynamic radius are well known in the art, such as by the use of size exclusion chromatography (SEC), as described in U.S. Pat. Nos. 6,406,632 and 7,294,513. As the results of Example 19 demonstrate, the addition of increasing lengths of XTEN results in proportional increases in the parameters of hydrodynamic radius, Apparent Molecular Weight, and Apparent Molecular Weight Factor, permitting the tailoring of BPXTEN to desired characteristic cut-off Apparent Molecular Weights or hydrodynamic radii. Accordingly, in certain embodiments, the BPXTEN fusion protein can be configured with an XTEN such that the fusion protein can have a hydrodynamic radius of at least about 5 nm, or at least about 8 nm, or at least about 10 nm, or 12 nm, or at least about 15 nm. In the foregoing embodiments, the large hydrodynamic radius conferred by the XTEN in an BPXTEN fusion protein can lead to reduced renal clearance of the resulting fusion protein, leading to a corresponding increase in terminal half-life, an increase in mean residence time, and/or a decrease in renal clearance rate.
In another embodiment, an XTEN of a chosen length and sequence can be selectively incorporated into a BPXTEN to create a fusion protein that will have, under physiologic conditions, an Apparent Molecular Weight of at least about 150 kDa, or at least about 300 kDa. or at least about 400 kDa, or at least about 500 kDA, or at least about 600 kDa, or at least about 700 kDA, or at least about 800 kDa, or at least about 900 kDa, or at least about 1000 kDa, or at least about 1200 kDa, or at least about 1500 kDa, or at least about 1800 kDa, or at least about 2000 kDa, or at least about 2300 kDa or more. In another embodiment, an XTEN of a chosen length and sequence can be selectively linked to a BP to result in a BPXTEN fusion protein that has, under physiologic conditions, an Apparent Molecular Weight Factor of at least three, alternatively of at least four, alternatively of at least five, alternatively of at least six, alternatively of at least eight, alternatively of at least 10, alternatively of at least 15, or an Apparent Molecular Weight Factor of at least 20 or greater. In another embodiment, the BPXTEN fusion protein has, under physiologic conditions, an Apparent Molecular Weight Factor that is about 4 to about 20, or is about 6 to about 15, or is about 8 to about 12, or is about 9 to about 10 relative to the actual molecular weight of the fusion protein.
III). Biologically Active Proteins of the BXTEN Fusion Protein Compositions
The present invention relates in part to fusion protein compositions comprising biologically active proteins and XTEN and the uses thereof for the treatment of diseases, disorders or conditions of a subject.
In one aspect, the invention provides at least a first biologically active protein (hereinafter “BP”) covalently linked to a fusion protein comprising one or more extended recombinant polypeptides (“XTEN”), resulting in an XTEN fusion protein composition (hereinafter “BPXTEN”). As described more fully below, the fusion proteins can optionally include spacer sequences that can further comprise cleavage sequences to release the BP from the fusion protein when acted on by a protease.
The term “BPXTEN”, as used herein, is meant to encompass fusion polypeptides that comprise one or two payload regions each comprising a biologically active protein that mediates one or more biological or therapeutic activities and at least one other region comprising at least one XTEN polypeptide.
The BP of the subject compositions, particularly those disclosed in Tables 3-8, together with their corresponding nucleic acid and amino acid sequences, are well known in the art and descriptions and sequences are available in public databases such as Chemical Abstracts Services Databases (e.g., the CAS Registry), GenBank, The Universal Protein Resource (UniProt) and subscription provided databases such as GenSeq (e.g., Derwent). Polynucleotide sequences may be a wild type polynucleotide sequence encoding a given BP (e.g., either full length or mature), or in some instances the sequence may be a variant of the wild type polynucleotide sequence (e.g., a polynucleotide which encodes the wild type biologically active protein, wherein the DNA sequence of the polynucleotide has been optimized, for example, for expression in a particular species, or a polynucleotide encoding a variant of the wild type protein, such as a site directed mutant or an allelic variant. It is well within the ability of the skilled artisan to use a wild-type or consensus cDNA sequence or a codon-optimized variant of a BP to create BPXTEN constructs contemplated by the invention using methods known in the art and/or in conjunction with the guidance and methods provided herein, and described more fully in the Examples.
The BP for inclusion in the BPXTEN of the invention can include any protein of biologic, therapeutic, prophylactic, or diagnostic interest or function, or that is useful for mediating a biological activity or preventing or ameliorating a disease, disorder or conditions when administered to a subject. Of particular interest are BP for which an increase in a pharmacokinetic parameter, increased solubility, increased stability, or some other enhanced pharmaceutical property is sought, or those BP for which increasing the terminal half-life would improve efficacy, safety, or result in reduce dosing frequency and/or improve patient compliance. Thus, the BPXTEN fusion protein compositions are prepared with various objectives in mind, including improving the therapeutic efficacy of the bioactive compound by, for example, increasing the in vivo exposure or the length that the BPXTEN remains within the therapeutic window when administered to a subject, compared to a BP not linked to XTEN.
A BP of the invention can be a native, full-length protein or can be a fragment or a sequence variant of a biologically active protein that retains at least a portion of the biological activity of the native protein.
In one embodiment, the BP incorporated into the subject compositions can be a recombinant polypeptide with a sequence corresponding to a protein found in nature. In another embodiment, the BP can be sequence variants, fragments, homologs, and mimetics of a natural sequence that retain at least a portion of the biological activity of the native BP. In non-limiting examples, a BP can be a sequence that exhibits at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a protein sequence selected from Tables 3-8. In one embodiment, a BPXTEN fusion protein can comprise a single BP molecule linked to an XTEN (as described more fully below). In another embodiment, the BPXTEN can comprise a first BP and a second molecule of the same BP, resulting in a fusion protein comprising the two BP linked to one or more XTEN (for example, two molecules of glucagon, or two molecules of hGH).
In general, BP will exhibit a binding specificity to a given target or another desired biological characteristic when used in vivo or when utilized in an in vitro assay. For example, the BP can be an agonist, a receptor, a ligand, an antagonist, an enzyme, or a hormone. Of particular interest are BP used or known to be useful for a disease or disorder wherein the native BP have a relatively short terminal half-life and for which an enhancement of a pharmacokinetic parameter (which optionally could be released from the fusion protein by cleavage of a spacer sequence) would permit less frequent dosing or an enhanced pharmacologic effect. Also of interest are BP that have a narrow therapeutic window between the minimum effective dose or blood concentration (Cmin) and the maximum tolerated dose or blood concentration (Cmax). In such cases, the linking of the BP to a fusion protein comprising a select XTEN sequence(s) can result in an improvement in these properties, making them more useful as therapeutic or preventive agents compared to BP not linked to XTEN.
The BP encompassed by the inventive compositions can have utility in the treatment in various therapeutic or disease categories, including but not limited to glucose and insulin disorders, metabolic disorders, cardiovascular diseases, coagulation/bleeding disorders, growth disorders or conditions, tumorigenic conditions, inflammatory conditions, autoimmune conditions, etc.
(a) Glucose-Regulating Peptides
Endocrine and obesity-related diseases or disorders have reached epidemic proportions in most developed nations, and represent a substantial and increasing health care burden in most developed nations, which include a large variety of conditions affecting the organs, tissues, and circulatory system of the body. Of particular concern are endocrine and obesity-related diseases and disorders, which. Chief amongst these is diabetes, one of the leading causes of death in the United States. Diabetes is divided into two major sub-classes-Type I, also known as juvenile diabetes, or Insulin-Dependent Diabetes Mellitus (IDDM), and Type II, also known as adult onset diabetes, or Non-Insulin-Dependent Diabetes Mellitus (NIDDM). Type 1 Diabetes is a form of autoimmune disease that completely or partially destroys the insulin producing cells of the pancreas in such subjects, and requires use of exogenous insulin during their lifetime. Even in well-managed subjects, episodic complications can occur, some of which are life-threatening.
In Type II diabetics, rising blood glucose levels after meals do not properly stimulate insulin production by the pancreas. Additionally, peripheral tissues are generally resistant to the effects of insulin, and such subjects often have higher than normal plasma insulin levels (hyperinsulinemia) as the body attempts to overcome its insulin resistance. In advanced disease states insulin secretion is also impaired.
Insulin resistance and hyperinsulinemia have also been linked with two other metabolic disorders that pose considerable health risks: impaired glucose tolerance and metabolic obesity. Impaired glucose tolerance is characterized by normal glucose levels before eating, with a tendency toward elevated levels (hyperglycemia) following a meal. These individuals are considered to be at higher risk for diabetes and coronary artery disease. Obesity is also a risk factor for the group of conditions called insulin resistance syndrome, or “Syndrome X,” as is hypertension, coronary artery disease (arteriosclerosis), and lactic acidosis, as well as related disease states. The pathogenesis of obesity is believed to be multifactorial but an underlying problem is that in the obese, nutrient availability and energy expenditure are not in balance until there is excess adipose tissue. Other related diseases or disorders include, but are not limited to, gestational diabetes, juvenile diabetes, obesity, excessive appetite, insufficient satiety, metabolic disorder, glucagonomas, retinal neurodegenerative processes, and the “honeymoon period” of Type I diabetes.
Dyslipidemia is a frequent occurrence among diabetics; typically characterized by elevated plasma triglycerides, low HDL (high density lipoprotein) cholesterol, normal to elevated levels of LDL (low density lipoprotein) cholesterol and increased levels of small dense, LDL particles in the blood. Dyslipidemia is a main contributor to an increased incidence of coronary events and deaths among diabetic subjects.
Most metabolic processes in glucose homeostatis and insulin response are regulated by multiple peptides and hormones, and many such peptides and hormones, as well as analogues thereof, have found utility in the treatment of metabolic diseases and disorders. Many of these peptides tend to be highly homologous to each other, even when they possess opposite biological functions. Glucose-increasing peptides are exemplified by the peptide hormone glucagon, while glucose-lowering peptides include exendin-4, glucagon-like peptide 1, and amylin. However, the use of therapeutic peptides and/or hormones, even when augmented by the use of small molecule drugs, has met with limited success in the management of such diseases and disorders. In particular, dose optimization is important for drugs and biologics used in the treatment of metabolic diseases, especially those with a narrow therapeutic window. Hormones in general, and peptides involved in glucose homeostasis often have a narrow therapeutic window. The narrow therapeutic window, coupled with the fact that such hormones and peptides typically have a short half-life, which necessitates frequent dosing in order to achieve clinical benefit, results in difficulties in the management of such patients. While chemical modifications to a therapeutic protein, such as pegylation, can modify its in vivo clearance rate and subsequent serum half-life, it requires additional manufacturing steps and results in a heterogeneous final product. In addition, unacceptable side effects from chronic administration have been reported. Alternatively, genetic modification by fusion of an Fc domain to the therapeutic protein or peptide increases the size of the therapeutic protein, reducing the rate of clearance through the kidney, and promotes recycling from lysosomes by the FcRn receptor. Unfortunately, the Fc domain does not fold efficiently during recombinant expression and tends to form insoluble precipitates known as inclusion bodies. These inclusion bodies must be solubilized and functional protein must be renatured, a time-consuming, inefficient, and expensive process.
Thus, one aspect of the present invention is the incorporation of peptides involved in glucose homoestasis, insulin resistance and obesity (collectively, “glucose regulating peptides”) in BPXTEN fusion proteins to create compositions with utility in the treatment of glucose, insulin, and obesity disorders, disease and related conditions. Glucose regulating peptides can include any protein of biologic, therapeutic, or prophylactic interest or function that is useful for preventing, treating, mediating, or ameliorating a disease, disorder or condition of glucose homeostasis or insulin resistance or obesity. Suitable glucose-regulating peptides that can be linked to the XTEN to create BPXTEN include all biologically active polypeptides that increase glucose-dependent secretion of insulin by pancreatic beta-cells or potentiate the action of insulin. Glucose-regulating peptides can also include all biologically active polypeptides that stimulate pro-insulin gene transcription in the pancreatic beta-cells. Furthermore, glucose-regulating peptides can also include all biologically active polypeptides that slow down gastric emptying time and reduce food intake. Glucose-regulating peptides can also include all biologically active polypeptides that inhibit glucagon release from the alpha cells of the Islets of Langerhans. Table 3 provides a non-limiting list of sequences of glucose regulating peptides that are encompassed by the BPXTEN fusion proteins of the invention. Glucose regulating peptides of the inventive BPXTEN compositions can be a peptide that exhibits at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a protein sequence selected from Tables 3.
“Adrenomedullin” or “ADM” means the human adrenomedulin peptide hormone and species and sequence variants thereof having at least a portion of the biological activity of mature ADM. ADM is generated from a 185 amino acid preprohormone through consecutive enzymatic cleavage and amidation, resulting in a 52 amino acid bioactive peptide with a measured plasma half-life of 22 min. ADM-containing fusion proteins of the invention may find particular use in diabetes for stimulatory effects on insulin secretion from islet cells for glucose regulation or in subjects with sustained hypotension. The complete genomic infrastructure for human AM has been reported (Ishimitsu, et al., Biochem. Biophys. Res. Commun 203:631-639 (1994)), and analogs of ADM peptides have been cloned, as described in U.S. Pat. No. 6,320,022. “Amylin” means the human peptide hormone referred to as amylin, pramlintide, and species variations thereof, as described in U.S. Pat. No. 5,234,906, having at least a portion of the biological activity of mature amylin.
Amylin is a 37-amino acid polypeptide hormone co-secreted with insulin by pancreatic beta cells in response to nutrient intake (Koda et al., Lancet 339:1179-1180, 1992), and has been reported to modulate several key pathways of carbohydrate metabolism, including incorporation of glucose into glycogen. Amylin-containing fusion proteins of the invention may find particular use in diabetes and obesity for regulating gastric emptying, suppressing glucagon secretion and food intake, thereby affecting the rate of glucose appearance in the circulation. Thus, the fusion proteins may complement the action of insulin, which regulates the rate of glucose disappearance from the circulation and its uptake by peripheral tissues. Amylin analogues have been cloned, as described in U.S. Pat. Nos. 5,686,411 and 7,271,238. Amylin mimetics can be created that retain biologic activity. For example, pramlintide has the sequence KCNTATCATNRLANFLVHSSNNFGPILPPTNVGSNTY (SEQ ID NO: 43), wherein amino acids from the rat amylin sequence are substituted for amino acids in the human amylin sequence. In one embodiment, the invention contemplates fusion proteins comprising amylin mimetics of the sequence
wherein X1 is independently N or Q and X2 is independently S, P or G. In one embodiment, the amylin mimetic incorporated into a BPXTEN can have the sequence KCNTATCATNRLANFLVHSSNNFGGILGGTNVGSNTY (SEQ ID NO: 45). In another embodiment, wherein the amylin mimetic is used at the C-terminus of the BPXTEN, the mimetic can have the sequence KCNTATCATNRLANFLVHSSNNFGGILGGTNVGSNTY(NH2) (SEQ ID NO: 46).
“Calcitonin” (CT) means the human calcitonin protein and species and sequence variants thereof, including salmon calcitonin (“sCT”), having at least a portion of the biological activity of mature CT. CT is a 32 amino acid peptide cleaved from a larger prohormone of the thyroid that appears to function in the nervous and vascular systems, but has also been reported to be a potent hormonal mediator of the satiety reflex. CT is named for its secretion in response to induced hypercalcemia and its rapid hypocalcemic effect. It is produced in and secreted from neuroendocrine cells in the thyroid termed C cells. CT has effects on the osteoclast, and the inhibition of osteoclast functions by CT results in a decrease in bone resorption. In vitro effects of CT include the rapid loss of ruffled borders and decreased release of lysosomal enzymes. A major function of CT(1-32) is to combat acute hypercalcemia in emergency situations and/or protect the skeleton during periods of “calcium stress” such as growth, pregnancy, and lactation. (Reviewed in Becker, JCEM, 89(4): 1512-1525 (2004) and Sexton. Current Medicinal Chemistry 6: 1067-1093 (1999)). Calcitonin-containing fusion proteins of the invention may find particular use for the treatment of osteoporosis and as a therapy for Paget's disease of bone. Synthetic calcitonin peptides have been created, as described in U.S. Pat. Nos. 5,175,146 and 5,364,840.
“Calcitonin gene related peptide” or “CGRP” means the human CGRP peptide and species and sequence variants thereof having at least a portion of the biological activity of mature CGRP. Calcitonin gene related peptide is a member of the calcitonin family of peptides, which in humans exists in two forms, α-CGRP (a 37 amino acid peptide) and β-CGRP. CGRP has 43-46% sequence identity with human amylin. CGRP-containing fusion proteins of the invention may find particular use in decreasing morbidity associated with diabetes, ameliorating hyperglycemia and insulin deficiency, inhibition of lymphocyte infiltration into the islets, and protection of beta cells against autoimmune destruction. Methods for making synthetic and recombinant CGRP are described in U.S. Pat. No. 5,374,618.
“Cholecystokinin” or “CCK” means the human CCK peptide and species and sequence variants thereof having at least a portion of the biological activity of mature CCK. CCK-58 is the mature sequence, while the CCK-33 amino acid sequence first identified in humans is the major circulating form of the peptide. The CCK family also includes an 8-amino acid in vivo C-terminal fragment (“CCK-8”), pentagastrin or CCK-5 being the C-terminal peptide CCK(29-33), and CCK-4 being the C-terminal tetrapeptide CCK(30-33). CCK is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein. CCK-33 and CCK-8-containing fusion proteins of the invention may find particular use in reducing the increase in circulating glucose after meal ingestion and potentiating the increase in circulating insulin. Analogues of CCK-8 have been prepared, as described in U.S. Pat. No. 5,631,230.
“Exendin-3” means a glucose regulating peptide isolated from Heloderma horridum and sequence variants thereof having at least a portion of the biological activity of mature exendin-3. Exendin-3 amide is a specific exendin receptor antagonist from that mediates an increase in pancreatic cAMP, and release of insulin and amylase. Exendin-3-containing fusion proteins of the invention may find particular use in the treatment of diabetes and insulin resistance disorders. The sequence and methods for its assay are described in U.S. Pat. No. 5,424,286.
Exendin-4” means a glucose regulating peptide found in the saliva of the Gila-monster Heloderma suspectum. as well as species and sequence variants thereof, and includes the native 39 amino acid sequence His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Leu-Ser-Lys-Gn-Met-Glu-Glu-Glu-Ala-Val-Arg-Leu-Phe-Ile-Glu-Trp-Leu-Lys-Asn-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser (SEQ ID NO: 47) and homologous sequences and peptide mimetics, and variants thereof; natural sequences, such as from primates and non-natural having at least a portion of the biological activity of mature exendin-4. Exendin-4 is an incretin polypeptide hormone that decreases blood glucose, promotes insulin secretion, slows gastric emptying and improves satiety, providing a marked improvement in postprandial hyperglycemia. The exendins have some sequence similarity to members of the glucagon-like peptide family, with the highest identity being to GLP-1 (Goke, et al., J. Biol. Chem., 268:19650-55 (1993)). A variety of homologous sequences can be functionally equivalent to native exendin-4 and GLP-1. Conservation of GLP-1 sequences from different species are presented in Regulatory Peptides 2001 98 p. 1-12. Table 4 shows the sequences from a wide variety of species, while Table 5 shows a list of synthetic GLP-1 analogs, all of which are contemplated for use in the BPXTEN described herein. Exendin-4 binds at GLP-1 receptors on insulin-secreting βTC1 cells, and also stimulates somatostatin release and inhibits gastrin release in isolated stomachs (Goke, et al., J. Biol. Chem. 268:19650-55, 1993). As a mimetic of GLP-1, exendin-4 displays a similar broad range of biological activities, yet has a longer half-life than GLP-1, with a mean terminal half-life of 2.4 h. Exenatide is a synthetic version of exendin-4, marketed as Byetta. However, due to its short half-life, exenatide is currently dosed twice daily, limiting its utility. Exendin-4-containing fusion proteins of the invention may find particular use in the treatment of diabetes and insulin resistance disorders.
‘Fibroblast growth factor 21’, or “FGF-21” means the human protein encoded by the FGF21 gene, or species and sequence variants thereof having at least a portion of the biological activity of mature FGF21. FGF-21 stimulates glucose uptake in adipocytes but not in other cell types; the effect is additive to the activity of insulin. FGF-21 injection in ob/ob mice results in an increase in Glut1 in adipose tissue. FGF21 also protects animals from diet-induced obesity when over expressed in transgenic mice and lowers blood glucose and triglyceride levels when administered to diabetic rodents (Kharitonenkov A, et al., (2005). “FGF-21 as a novel metabolic regulator”. J. Clin. Invest. 115: 1627-35). FGF-21-containing fusion proteins of the invention may find particular use in treatment of diabetes, including causing increased energy expenditure, fat utilization and lipid excretion. FGF-21 has been cloned, as disclosed in U.S. Pat. No. 6,716,626.
“FGF-19”, or “fibroblast growth factor 19” means the human protein encoded by the FGF19 gene, or species and sequence variants thereof having at least a portion of the biological activity of mature FGF-19. FGF-19 is a protein member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes. FGF-19 increases liver expression of the leptin receptor, metabolic rate, stimulates glucose uptake in adipocytes, and leads to loss of weight in an obese mouse model (Fu, L, et al. FGF-19-containing fusion proteins of the invention may find particular use in increasing metabolic rate and reversal of dietary and leptin-deficient diabetes. FGF-19 has been cloned and expressed, as described in US Patent Application No. 20020042367.
“Gastrin” means the human gastrin peptide, truncated versions, and species and sequence variants thereof having at least a portion of the biological activity of mature gastrin. Gastrin is a linear peptide hormone produced by G cells of the duodenum and in the pyloric antrum of the stomach and is secreted into the bloodstream. Gastrin is found primarily in three forms: gastrin-34 (“big gastrin”): gastrin-17 (“little gastrin”); and gastrin-14 (“minigastrin”). It shares sequence homology with CCK. Gastrin-containing fusion proteins of the invention may find particular use in the treatment of obesity and diabetes for glucose regulation. Gastrin has been synthesized, as described in U.S. Pat. No. 5,843,446.
“Ghrelin” means the human hormone that induces satiation, or species and sequence variants thereof, including the native, processed 27 or 28 amino acid sequence and homologous sequences. Ghrelin is produced mainly by P/D1 cells lining the fundus of the human stomach and epsilon cells of the pancreas that stimulates hunger, and is considered the counterpart hormone to leptin. Ghrelin levels increase before meals and decrease after meals, and can result in increased food intake and increase fat mass by an action exerted at the level of the hypothalamus. Ghrelin also stimulates the release of growth hormone. Ghrelin is acylated at a serine residue by n-octanoic acid; this acylation is essential for binding to the GHS1a receptor and for the GH-releasing capacity of ghrelin. Ghrelin-containing fusion proteins of the invention may find particular use as agonists; e.g., to selectively stimulate motility of the GI tract in gastrointestinal motility disorder, to accelerate gastric emptying, or to stimulate the release of growth hormone. Ghrelin analogs with sequence substitutions or truncated variants, such as described in U.S. Pat. No. 7,385,026, may find particular use as fusion partners to XTEN for use as antagonists for improved glucose homeostasis, treatment of insulin resistance and treatment of obesity. The isolation and characterization of ghrelin has been reported (Kojima M, et al., Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999; 402(6762):656-660.) and synthetic analogs have been prepared by peptide synthesis, as described in U.S. Pat. No. 6,967,237.
“Glucagon” means the human glucagon glucose regulating peptide, or species and sequence variants thereof, including the native 29 amino acid sequence and homologous sequences; natural, such as from primates, and non-natural sequence variants having at least a portion of the biological activity of mature glucagon. The term “glucagon” as used herein also includes peptide mimetics of glucagon. Native glucagon is produced by the pancreas, released when blood glucose levels start to fall too low, causing the liver to convert stored glycogen into glucose and release it into the bloodstream. While the action of glucagon is opposite that of insulin, which signals the body's cells to take in glucose from the blood, glucagon also stimulates the release of insulin, so that newly-available glucose in the bloodstream can be taken up and used by insulin-dependent tissues. Glucagon-containing fusion proteins of the invention may find particular use in increasing blood glucose levels in individuals with extant hepatic glycogen stores and maintaining glucose homeostasis in diabetes. Glucagon has been cloned, as disclosed in U.S. Pat. No. 4,826,763.
“GLP-1” means human glucagon like peptide-1 and sequence variants thereof having at least a portion of the biological activity of mature GLP-1. The term “GLP-1” includes human GLP-1(1-37), GLP-1(7-37), and GLP-1(7-36)amide. GLP-1 stimulates insulin secretion, but only during periods of hyperglycemia. The safety of GLP-1 compared to insulin is enhanced by this property and by the observation that the amount of insulin secreted is proportional to the magnitude of the hyperglycemia. The biological half-life of GLP-1(7-37)OH is a mere 3 to 5 minutes (U.S. Pat. No. 5,118,666). GLP-1-containing fusion proteins of the invention may find particular use in the treatment of diabetes and insulin-resistance disorders for glucose regulation. GLP-1 has been cloned and derivatives prepared, as described in U.S. Pat. No. 5,118,666. Non-limited examples of GLP-1 sequences from a wide variety of species are shown in Table 4, while Table 5 shows the sequences of a number of synthetic GLP-1 analogs; all of which are contemplated for use in the BPXTEN compositions described herein.
musculus]
GLP native sequences may be described by several sequence motifs, which are presented below. Letters in brackets represent acceptable amino acids at each sequence position: [HVY] [IAGISTV] [DEHQ] [AG] [ILMPSTV] [FLY] [DINST] [ADEKNST] [ADENSTV] [LMVY] [ANRSTY] [EHIKNQRST] [AHILMQVY] [ILMRT] [ADEGKQS] [ADEGKNQSY] [AEIKLMQR] [AKQRSVY] [AILMQSTV] [GKQR] [DEKLQR] [FHLVWY] [ILV] [ADEGHIKNQRST] [ADEGNRSTW] [GILVW] [AIKLMQSV][ADGIKNQRST] [GKRSY]. In addition, synthetic analogs of GLP-1 can be useful as fusion partners to XTEN to create BPXTEN with biological activity useful in treatment of glucose-related disorders. Further sequences homologous to Exendin-4 or GLP-1 may be found by standard homology searching techniques.
“GLP-2” means human glucagon like peptide-2 and sequence variants thereof having at least a portion of the biological activity of mature GLP-2. More particularly, GLP-2 is a 33 amino acid peptide, co-secreted along with GLP-1 from intestinal endocrine cells in the small and large intestine.
“IGF-1” or “Insulin-like growth factor 1” means the human IGF-1 protein and species and sequence variants thereof having at least a portion of the biological activity of mature IGF-1. IGF-1, which was once called somatomedin C, is a polypeptide protein anabolic hormone similar in molecular structure to insulin, and that modulates the action of growth hormone. IGF-1 consists of 70 amino acids and is produced primarily by the liver as an endocrine hormone as well as in target tissues in a paracrine/autocrine fashion. IGF-1-containing fusion proteins of the invention may find particular use in the treatment of diabetes and insulin-resistance disorders for glucose regulation. IGF-1 has been cloned and expressed in E. coli and yeast, as described in U.S. Pat. No. 5,324,639.
“IGF-2” or “Insulin-like growth factor 2” means the human IGF-2 protein and species and sequence variants thereof having at least a portion of the biological activity of mature IGF-2. IGF-2 is a polypeptide protein hormone similar in molecular structure to insulin, with a primary role as a growth-promoting hormone during gestation. IGF-2 has been cloned, as described in Bell G I, et al. Isolation of the human insulin-like growth factor genes: insulin-like growth factor II and insulin genes are contiguous. Proc Natl Acad Sci USA. 1985. 82(19):6450-4.
“INGAP”, or “islet neogenesis-associated protein”, or “pancreatic beta cell growth factor” means the human INGAP peptide and species and sequence variants thereof having at least a portion of the biological activity of mature INGAP. INGAP is capable of initiating duct cell proliferation, a prerequisite for islet neogenesis. INGAP-containing fusion proteins of the invention may find particular use in the treatment or prevention of diabetes and insulin-resistance disorders. INGAP has been cloned and expressed, as described in R Rafacloff R, et al., Cloning and sequencing of the pancreatic islet neogenesis associated protein (INGAP) gene and its expression in islet neogenesis in hamsters. J Clin Invest. 1997. 99(9): 2100-2109.
“Intermedin” or “AFP-6” means the human intermedin peptide and species and sequence variants thereof having at least a portion of the biological activity of mature intermedin. Intermedin is a ligand for the calcitonin receptor-like receptor. Intermedin treatment leads to blood pressure reduction both in normal and hypertensive subjects, as well as the suppression of gastric emptying activity, and is implicated in glucose homeostasis. Intermedin-containing fusion proteins of the invention may find particular use in the treatment of diabetes, insulin-resistance disorders, and obesity. Intermedin peptides and variants have been cloned, as described in U.S. Pat. No. 6,965,013.
“Leptin” means the naturally occurring leptin from any species, as well as biologically active D-isoforms, or fragments and sequence variants thereof. Leptin plays a key role in regulating energy intake and energy expenditure, including appetite and metabolism. Leptin-containing fusion proteins of the invention may find particular use in the treatment of diabetes for glucose regulation, insulin-resistance disorders, and obesity. Leptin is the polypeptide product of the ob gene as described in the International Patent Pub. No. WO 96/05309. Leptin has been cloned, as described in U.S. Pat. No. 7,112,659, and leptin analogs and fragments in U.S. Pat. No. 5,521,283, U.S. Pat. No. 5,532,336, PCT/US96/22308 and PCT/US96/01471.
“Neuromedin” means the neuromedin family of peptides including neuromedin U and S peptides, and sequence variants thereof. The native active human neuromedin U peptide hormone is neuromedin-U25, particularly its amide form. Of particular interest are their processed active peptide hormones and analogs, derivatives and fragments thereof. Included in the neuromedin U family are various truncated or splice variants, e.g., FLFHYSKTQKLGKSNVVEELQSPFASQSRGYFLFRPRN (SEQ ID NO: 180). Exemplary of the neuromedin S family is human neuromedin S with the sequence ILQRGSGTAAVDFTKKDHTATWGRPFFLFRPRN (SEQ ID NO: 181), particularly its amide form. Neuromedin fusion proteins of the invention may find particular use in treating obesity, diabetes, reducing food intake, and other related conditions and disorders as described herein. Of particular interest are neuromedin modules combined with an amylin family peptide, an exendin peptide family or a GLP I peptide family module.
“Oxyntomodulin”, or “OXM” means human oxyntomodulin and species and sequence variants thereof having at least a portion of the biological activity of mature OXM. OXM is a 37 amino acid peptide produced in the colon that contains the 29 amino acid sequence of glucagon followed by an 8 amino acid carboxyterminal extension. OXM has been found to suppress appetite. OXM-containing fusion proteins of the invention may find particular use in the treatment of diabetes for glucose regulation, insulin-resistance disorders, obesity, and can be used as a weight loss treatment.
“PYY” means human peptide YY polypeptide and species and sequence variants thereof having at least a portion of the biological activity of mature PYY. PYY includes both the human full length, 36 amino acid peptide, PYY1-36 and PYY3-36 which have the PP fold structural motif. PYY inhibits gastric motility and increases water and electrolyte absorption in the colon. PYY may also suppress pancreatic secretion. PPY-containing fusion proteins of the invention may find particular use in the treatment of diabetes for glucose regulation, insulin-resistance disorders, and obesity. Analogs of PYY have been prepared, as described in U.S. Pat. Nos. 5,604,203, 5,574,010 and 7,166,575.
“Urocortin” means a human urocortin peptide hormone and sequence variants thereof having at least a portion of the biological activity of mature urocortin. There are three human urocortins: Ucn-1. Ucn-2 and Ucn-3. Further urocortins and analogs have been described in U.S. Pat. No. 6,214,797. Urocortins Ucn-2 and Ucn-3 have food-intake suppression, antihypertensive, cardioprotective, and inotropic properties. Ucn-2 and Ucn-3 have the ability to suppress the chronic HPA activation following a stressful stimulus such as dieting/fasting, and are specific for the CRF type 2 receptor and do not activate CRF-R1 which mediates ACTH release. BPXTEN comprising urocortin, e.g., Ucn-2 or Ucn-3, may be useful for vasodilation and thus for cardiovascular uses such as chronic heart failure. Urocortin-containing fusion proteins of the invention may also find particular use in treating or preventing conditions associated with stimulating ACTH release, hypertension due to vasodilatory effects, inflammation mediated via other than ACTH elevation, hyperthermia, appetite disorder, congestive heart failure, stress, anxiety, and psoriasis. Urocortin-containing fusion proteins may also be combined with a natriuretic peptide module, amylin family, and exendin family, or a GLP1 family module to provide an enhanced cardiovascular benefit, e.g. treating CHF, as by providing a beneficial vasodilation effect.
Metabolic and cardiovascular diseases represent a substantial health care burden in most developed nations, with cardiovascular diseases remaining the number one cause of death and disability in the United States and most European countries. Metabolic diseases and disorders include a large variety of conditions affecting the organs, tissues, and circulatory system of the body. Chief amongst these is diabetes; one of the leading causes of death in the United States, as it results in pathology and metabolic dysfunction in both the vasculature, central nervous system, major organs, and peripheral tissues. Insulin resistance and hyperinsulinemia have also been linked with two other metabolic disorders that pose considerable health risks: impaired glucose tolerance and metabolic obesity. Impaired glucose tolerance is characterized by normal glucose levels before eating, with a tendency toward elevated levels (hyperglycemia) following a meal. These individuals are considered to be at higher risk for diabetes and coronary artery disease. Obesity is also a risk factor for the group of conditions called insulin resistance syndrome, or “Syndrome X,” as is hypertension, coronary artery disease (arteriosclerosis), and lactic acidosis, as well as related disease states. The pathogenesis of obesity is believed to be multifactorial but an underlying problem is that in the obese, nutrient availability and energy expenditure are not in balance until there is excess adipose tissue.
Dyslipidemia is a frequent occurrence among diabetics and subjects with cardiovascular disease, typically characterized by parameters such as elevated plasma triglycerides, low HDL (high density lipoprotein) cholesterol, normal to elevated levels of LDL (low density lipoprotein) cholesterol and increased levels of small dense, LDL particles in the blood. Dyslipidemia and hypertension is a main contributor to an increased incidence of coronary events, renal disease, and deaths among subjects with metabolic diseases like diabetes and cardiovascular disease.
Cardiovascular disease can be manifest by many disorders, symptoms and changes in clinical parameters involving the heart, vasculature and organ systems throughout the body, including aneurysms, angina, atherosclerosis, cerebrovascular accident (Stroke), cerebrovascular disease, congestive heart failure, coronary artery disease, myocardial infarction, reduced cardiac output and peripheral vascular disease, hypertension, hypotension, blood markers (e.g., C-reactive protein, BNP, and enzymes such as CPK, LDH, SGPT, SGOT), amongst others.
Most metabolic processes and many cardiovascular parameters are regulated by multiple peptides and hormones (“metabolic proteins”), and many such peptides and hormones, as well as analogues thereof, have found utility in the treatment of such diseases and disorders. However, the use of therapeutic peptides and/or hormones, even when augmented by the use of small molecule drugs, has met with limited success in the management of such diseases and disorders. In particular, dose optimization is important for drugs and biologics used in the treatment of metabolic diseases, especially those with a narrow therapeutic window. Hormones in general, and peptides involved in glucose homeostasis often have a narrow therapeutic window. The narrow therapeutic window, coupled with the fact that such hormones and peptides typically have a short half-life which necessitates frequent dosing in order to achieve clinical benefit, results in difficulties in the management of such patients. Therefore, there remains a need for therapeutics with increased efficacy and safety in the treatment of metabolic diseases.
Thus, one aspect of the present invention is the incorporation of biologically active metabolic proteins and involved in or used in the treatment of metabolic and cardiovascular diseases and disorders into BPXTEN fusion proteins to create compositions with utility in the treatment of such disorders, disease and related conditions. The metabolic proteins can include any protein of biologic, therapeutic, or prophylactic interest or function that is useful for preventing, treating, mediating, or ameliorating a metabolic or cardiovascular disease, disorder or condition. Table 6 provides a non-limiting list of such sequences of metabolic BPs that are encompassed by the BPXTEN fusion proteins of the invention. Metabolic proteins of the inventive BPXTEN compositions can be a protein that exhibits at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a protein sequence selected from Tables 6.
“Anti-CD3” means the monoclonal antibody against the T cell surface protein CD3, species and sequence variants, and fragments thereof, including OKT3 (also called muromonab) and humanized anti-CD3 monoclonal antibody (hOKT31(Ala-Ala))(KC Herold et al., New England Journal of Medicine 346:1692-1698. 2002) Anti-CD3 prevents T-cell activation and proliferation by binding the T-cell receptor complex present on all differentiated T cells. Anti-CD3-containing fusion proteins of the invention may find particular use to slow new-onset Type 1 diabetes, including use of the anti-CD3 as a therapeutic effector as well as a targeting moiety for a second therapeutic BP in the BPXTEN composition. The sequences for the variable region and the creation of anti-CD3 have been described in U.S. Pat. Nos. 5,885,573 and 6,491,916.
“IL-1ra” means the human IL-receptor antagonist protein and species and sequence variants thereof, including the sequence variant anakinra (Kineret®), having at least a portion of the biological activity of mature IL-1ra. Human IL-1ra is a mature glycoprotein of 152 amino acid residues. The inhibitory action of IL-1ra results from its binding to the type I IL-1 receptor. The protein has a native molecular weight of 25 kDa, and the molecule shows limited sequence homology to IL-1α (19%) and IL-1β (26%). Anakinra is a nonglycosylated, recombinant human IL-1ra and differs from endogenous human IL-1ra by the addition of an N-terminal methionine. A commercialized version of anakinra is marketed as Kineret®. It binds with the same avidity to IL-1 receptor as native IL-1ra and IL-1b, but does not result in receptor activation (signal transduction), an effect attributed to the presence of only one receptor binding motif on IL-1ra versus two such motifs on IL-1 α and IL-1β. Anakinra has 153 amino acids and 17.3 kD in size, and has a reported half-life of approximately 4-6 hours.
Increased IL-1 production has been reported in patients with various viral, bacterial, fungal, and parasitic infections; intravascular coagulation: high-dose IL-2 therapy; solid tumors; leukemias; Alzheimer's disease; HIV-1 infection; autoimmune disorders; trauma (surgery): hemodialysis; ischemic diseases (myocardial infarction): noninfectious hepatitis; asthma; UV radiation; closed head injury; pancreatitis; peritonitis: graft-versus-host disease; transplant rejection; and in healthy subjects after strenuous exercise. There is an association of increased IL-1b production in patients with Alzheimer's disease and a possible role for IL 1 in the release of the amyloid precursor protein. IL-1 has also been associated with diseases such as type 2 diabetes, obesity, hyperglycemia, hyperinsulinemia, type 1 diabetes, insulin resistance, retinal neurodegenerative processes, disease states and conditions characterized by insulin resistance, acute myocardial infarction (AMI), acute coronary syndrome (ACS), atherosclerosis, chronic inflammatory disorders, rheumatoid arthritis, degenerative intervertebral disc disease, sarcoidosis, Crohn's disease, ulcerative colitis, gestational diabetes, excessive appetite, insufficient satiety, metabolic disorders, glucagonomas, secretory disorders of the airway, osteoporosis, central nervous system disease, restenosis, neurodegenerative disease, renal failure, congestive heart failure, nephrotic syndrome, cirrhosis, pulmonary edema, hypertension, disorders wherein the reduction of food intake is desired, irritable bowel syndrome, myocardial infarction, stroke, post-surgical catabolic changes, hibernating myocardium, diabetic cardiomyopathy, insufficient urinary sodium excretion, excessive urinary potassium concentration, conditions or disorders associated with toxic hypervolemia, polycystic ovary syndrome, respiratory distress, chronic skin ulcers, nephropathy, left ventricular systolic dysfunction, gastrointestinal diarrhea, postoperative dumping syndrome, irritable bowel syndrome, critical illness polyneuropathy (CIPN), systemic inflammatory response syndrome (SIRS), dyslipidemia, reperfusion injury following ischemia, and coronary heart disease risk factor (CHDRF) syndrome. IL-1ra-containing fusion proteins of the invention may find particular use in the treatment of any of the foregoing diseases and disorders. IL-1ra has been cloned, as described in U.S. Pat. Nos. 5,075,222 and 6,858,409.
“Natriuretic peptides” means atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP or B-type natriuretic peptide) and C-type natriuretic peptide (CNP); both human and non-human species and sequence variants thereof having at least a portion of the biological activity of the mature counterpart natriuretic peptides. Alpha atrial natriuretic peptide (aANP) or (ANP) and brain natriuretic peptide (BNP) and type C natriuretic peptide (CNP) are homologous polypeptide hormones involved in the regulation of fluid and electrolyte homeostasis. Sequences of useful forms of natriuretic peptides are disclosed in U.S. Patent Publication 20010027181. Examples of ANPs include human ANP (Kangawa et al., BBRC 118:131 (1984)) or that from various species, including pig and rat ANP (Kangawa et al., BBRC 121:585 (1984)). Sequence analysis reveals that preproBNP consists of 134 residues and is cleaved to a 108-amino acid ProBNP. Cleavage of a 32-amino acid sequence from the C-terminal end of ProBNP results in human BNP (77-108), which is the circulating, physiologically active form. The 32-amino acid human BNP involves the formation of a disulfide bond (Sudoh et al., BBRC 159:1420 (1989)) and U.S. Pat. Nos. 5,114,923, 5,674,710, 5,674,710, and 5,948,761. BPXTEN-containing one or more natriuretic functions may be useful in treating hypertension, diuresis inducement, natriuresis inducement, vascular conduct dilatation or relaxation, natriuretic peptide receptors (such as NPR-A) binding, apida secretion suppression from the kidney, aldostrerone secretion suppression from the adrenal gland, treatment of cardiovascular diseases and disorders, reducing, stopping or reversing cardiac remodeling after a cardiac event or as a result of congestive heart failure, treatment of renal diseases and disorders; treatment or prevention of ischemic stroke, and treatment of asthma.
“FGF-2” or heparin-binding growth factor 2, means the human FGF-2 protein, and species and sequence variants thereof having at least a portion of the biological activity of the mature counterpart. FGF-2 had been shown to stimulate proliferation of neural stem cells differentiated into striatal-like neurons and protect striatal neurons in toxin-induced models of Huntington Disease, and also my have utility in treatment of cardiac reperfusion injury, and may have endothelial cell growth, anti-angiogenic and tumor suppressive properties, wound healing, as well as promoting fracture healing in bones. FGF-2 has been cloned, as described in Burgess, W. H. and Maciag, T., Ann. Rev. Biochem., 58:575-606 (1989); Coulier, F., et al., 1994, Prog. Growth Factor Res. 5:1; and the PCT publication WO 87/01728.
“TNF receptor” means the human receptor for TNF, and species and sequence variants thereof having at least a portion of the biological receptor activity of mature TNFR. P75 TNF Receptor molecule is the extracellular domain of p75 TNF receptor, which is from a family of structurally homologous receptors which includes the p55 TNF receptor. TNF α and TNF β (TNF ligands) compete for binding to the p55 and p75 TNF receptors. The x-ray crystal structure of the complex formed by the extracellular domain of the human p55 TNF receptor and TNF β has been determined (Banner et al. Cell 73:431, 1993, incorporated herein by reference).
(c) Coagulation Factors
In hemophilia the clotting of blood is disturbed by a lack of certain plasma blood clotting factors. Human factor IX (FIX) is a zymogen of a serine protease that is an important component of the intrinsic pathway of the blood coagulation cascade. In individuals who do not have FIX deficiency, the average half-life of FIX is short: approximately 18-24 hours. A deficiency of functional FIX, due to an X-linked disorder that occurs in about one in 30,000 males, results in hemophilia B, also known as Christmas disease. Over 100 mutations of factor IX have been described: some cause no symptoms, but many lead to a significant bleeding disorder. When untreated, hemophilia B is associated with uncontrolled bleeding into muscles, joints, and body cavities following injury, and may result in death. Previously, treatments for the disease included administration of FIX prepared from human plasma derived from donor pools, which carried attendant risks of infection with blood-borne viruses including human immunodeficiency virus (HIV) and hepatitis C virus (HCV). More recently, recombinant FIX products have become commercially available. The in vivo activity of exogenously supplied factor IX is limited both by protein half-life and inhibitors of coagulation, including antithrombin III. Factor IX compositions typically have short half-lives requiring frequent injections. Also, current FIX-based therapeutics require intravenous administration due to poor bioavailability. Thus, there is a need for factor IX compositions with extended half-life and retention of activity when administered as part of a preventive and/or therapeutic regimen for hemophilia B.
The physiological trigger of coagulation is the formation of a complex between tissue Factor (TF) and Factor VIIa (FVIIa) on the surface of TF expressing cells, which are normally located outside the vasculature. This leads to the activation of Factor IX and Factor X, ultimately generating some thrombin. In turn, thrombin activates Factor VIII and Factor IX, the so-called “intrinsic” arm of the blood coagulation cascade, thus amplifying the generation of Factor Xa, which is necessary for the generation of the full thrombin burst to achieve complete hemostasis. It was subsequently shown that by administering high concentrations of Factor VIIa, hemostasis can be achieved, bypassing the need for Factor Villa and Factor IXa in certain bleeding disorders. Coagulation and bleeding disorders can result in changes in such parameters as prothrombin time, partial prothrombin time, bleeding time, clotting time, platelet count, prothrombin fragment 1+2 (F1+2), thrombin-antithrombin III complex (TAT), D-dimer, incidence of bleeding episodes, erythrocyte sedimentation rate (ESR), C-reactive protein, and blood concentration of coagulation factors.
Thus, Factor VIIa (FVIIa) proteins have found utility for the treatment of bleeding episodes in hemophilia A or B patients with inhibitors to FVIII or FIX and in patients with acquired hemophilia, as well as prevention of bleeding in surgical interventions or invasive procedures in hemophilia A or B patients with inhibitors to FVIII or FIX. In addition, factor VIIa can be utilized in treatment of bleeding episodes in patients with congenital Factor VII deficiency and prevention of bleeding in surgical interventions or invasive procedures in patients with congenital FVII deficiency. However, the intravenous administration of products containing FVIIa can lead to side effects including thrombotic events, fever, and injection site reactions. In addition, the short half-life of Factor VIIa of approximately 2 hours, limits its application, and can require repeated injections every 2-4 hours to achieve hemostasis. Thus, there remains a need for factor IX and factor VIIa compositions with extended half-life and retention of activity when administered as part of a preventive and/or therapeutic regimen for hemophilia B, as well as formulations that reduce side effects and can be administered by both intravenous and subcutaneous routes.
The coagulation factors for inclusion in the BPXTEN of the invention can include proteins of biologic, therapeutic, or prophylactic interest or function that are useful for preventing, treating, mediating, or ameliorating blood coagulation disorders, diseases, or deficiencies. Suitable coagulation proteins include biologically active polypeptides that are involved in the coagulation cascade as substrates, enzymes or co-factors.
Table 7 provides a non-limiting list of sequences of coagulation factors that are encompassed by the BPXTEN fusion proteins of the invention. Coagulation factors for inclusion in the BPXTEN of the invention can be a protein that exhibits at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a protein sequence selected from Tables 7.
1735
MQRVNMIMAESPGLITICLLGYLLSAECTVFLDHENANKILNRPKRYNSGKLEEFV
“Factor IX” (“FIX”) includes the human Factor IX protein and species and sequence variants thereof having at least a portion of the biological receptor activity of mature Factor IX. FIX shall be any form of factor IX molecule with the typical characteristics of blood coagulation factor IX. FIX shall include FIX from plasma and any form of recombinant FIX which is capable of curing bleeding disorders in a patient; e.g., caused by deficiencies in FIX (e.g., hemophilia B). In some embodiments, the FIX peptide is a structural analog or peptide mimetic of any of the FIX peptides described herein, including the sequences of Table 7. Minor deletions, additions and/or substitutions of amino acids of the polypeptide sequence of FIX that do not abolish the biological activity of the polypeptide (i.e. reducing the activity to below 10% or even below 5% of the wild type form (=100%) are also included in the present application as biologically active derivatives, especially those with improved specific activity (above 100% activity of the wild-type form). The FIX according to the present invention may be derived from any vertebrate, e.g. a mammal.
In some embodiments, the FIX peptide is a structural analog or peptide mimetic of any of the FIX peptides described herein, including the sequences of Table 7. Minor deletions, additions and/or substitutions of amino acids of the polypeptide sequence of FIX that do not abolish the biological activity of the polypeptide (i.e. reducing the activity to below 10% or even below 5% of the wild type form (=100%)) are also included in the present application as biologically active derivatives, especially those with improved specific activity (above 100% activity of the wild-type form). The FIX according to the present invention may be derived from any vertebrate, e.g. a mammal. In one specific example of the present invention, the FIX is human FIX. In another embodiment, the FIX is a polypeptide sequence from Table 7.
Human Factor IX (FIX) is encoded by a single-copy gene residing on the X-chromosome at q27.1. The human FIX mRNA is composed of 205 bases for the 5′ untranslated region, 1383 bases for the prepro factor IX, a stop codon and 1392 bases for the 3′ untranslated region. The FIX polypeptide is 55 kDa, synthesized as a prepropolypetide chain composed of three regions: a signal peptide of 28 amino acids, a propeptide of 18 amino acids, which is required for gamma-carboxylation of glutamic acid residues, and a mature factor IX of 415 amino acids. The mature factor IX is composed of domains. The domains, in an N- to C-terminus configuration are a Gla domain, an EGF1 domain, a EGF2 domain, an activation peptide domain, and a protease (or catalytic) domain. The protease domain provides, upon activation of FIX to FIXa, the catalytic activity of FIX. Following activation, the single-chain FIX becomes a 2-chain molecule, in which the two chains are linked by a disulfide bond attaching the enzyme to the Gla domain. Activated factor VIII (FVIIIa) is the specific cofactor for the full expression of FIXa activity. As used herein “factor IX” and “FIX” are intended to encompass polypeptides that comprise the domains Gla, EGF1, EGF2, activation peptide, and protease, or synonyms of these domains known in the art.
FIX is expressed as a precursor polypeptide that requires posttranslational processing to yield active FIX. In particular, the precursor polypeptide of FIX requires gamma carboxylation of certain glutamic acid residues in the so-called gamma-carboxyglutamate domain and cleavage of propeptide. The propeptide is an 18-amino acid residue sequence N-terminal to the gamma-carboxyglutamate domain. The propeptide binds vitamin K-dependent gamma carboxylase and then is cleaved from the precursor polypeptide of FIX by an endogenous protease, most likely PACE (paired basic amino acid cleaving enzyme), also known as furin or PCSK3. Without the gamma carboxylation, the Gla domain is unable to bind calcium to assume the correct conformation necessary to anchor the protein to negatively charged phospholipid surfaces, thereby rendering Factor IX nonfunctional. Even if it is carboxylated, the Gla domain also depends on cleavage of the propeptide for proper function, since retained propeptide interferes with conformational changes of the Gla domain necessary for optimal binding to calcium and phospholipid. The resulting mature Factor IX is a single chain protein of 415 amino acid residues that contains approximately 17% carbohydrate by weight (Schmidt, A. E., et al. (2003) Trends Cardiovasc Med, 13: 39).
Mature FIX must be activated by activated Factor XI to yield Factor IXa. In the intrinsic pathway of the coagulation cascade, FIX associates with a complex of activated Factor VIII, Factor X, calcium, and phospholipid. In the complex. FIX is activated by Factor Xia. The activation of Factor IX is achieved by a two-step removal of the activation peptide (Ala 146-Arg 180) from the molecule. (Bajaj et al., “Human factor IX and factor IXa,” in METHODS IN ENZYMOLOGY. 1993). The first cleavage is made at the Arg 145-Ala 146 site by either Factor Xia or Factor VIIa/tissue factor. The second, and rate limiting cleavage is made at Arg 180-Val 181. The activation removes 35 residues. Activated human Factor IX exists as a disulfide linked heterodimer of the heavy chain and light chain. Factor IXa in turn activates Factor X in concert with activated Factor VIII. Alternatively, Factors IX and X can both be activated by Factor VIIa complexed with apidated Tissue Factor, generated via the extrinsic pathway. Factor Xa then participates in the final common pathway whereby prothrombin is converted to thrombin, and thrombin, in turn converts fibrinogen to fibrin to form the clot.
In some cases, the coagulation factor is Factor IX, a sequence variant of Factor IX, or a Factor IX moiety, such as the exemplary sequences of Table 7, as well as any protein or polypeptide substantially homologous thereto whose biological properties result in the activity of Factor IX. As used herein, the term “Factor IX moiety” includes proteins modified deliberately, as for example, by site directed mutagenesis or accidentally through mutations, that result in a factor IX sequence that retain at least some factor IX activity. The term “Factor IX moiety” also includes derivatives having at least one additional amino acid at the N- or carboxy terminal ends of the protein or internal to the Factor IX moiety sequence. Non-limiting examples of Factor IX moieties include the following: Factor IX; Factor IXa; truncated versions of Factor IX; hybrid proteins, and peptide mimetics having Factor IX activity. Biologically active fragments, deletion variants, substitution variants or addition variants of any of the foregoing that maintain at least some degree of Factor IX activity or the potential for activation can also serve as a Factor IX sequence.
“Factor VII” (FVII) means the human protein, and species and sequence variants thereof having at least a portion of the biological activity of activated Factor VII. Factor VII and recombinant human FVIIa has been introduced for use in uncontrollable bleeding in hemophilia patients (with Factor VIII or IX deficiency) who have developed inhibitors against replacement coagulation factor. Factor VII can be activated by thrombin, factor IXa, factor Xa or factor XIIa to FVIIa. FVII is converted to its active form Factor VIIa by proteolysis of the single peptide bond at Arg152-Ile153 leading to the formation of two polypeptide chains, a N-terminal light chain (24 kDa) and a C-terminal heavy chain (28 kDa), which are held together by one disulfide bridge. In contrast to other vitamin K-dependent coagulation factors no activation peptide, which is cleaved off during activation of these other vitamin-K dependent coagulation factors, has been described for FVII. The Arg152-Ile153 cleavage site and some amino acids downstream show homology to the activation cleavage site of other vitamin K-dependent polypeptides. Recombinant human factor VIIa has utility in treatment of uncontrollable bleeding in hemophilia patients (with Factor VIII or IX deficiency), including those who have developed inhibitors against replacement coagulation factor. FVII shall be any form of factor VII molecule with the typical characteristics of blood coagulation factor VII. FVII shall include FVII from plasma and any form of recombinant FVII which is capable of ameliorating bleeding disorders in a patient; e.g., caused by deficiencies in FVII/FVIIa. In some embodiments, the FVII peptide is the activated form (FVIIa), a structural analog or peptide mimetic of any of the FVII peptides described herein, including sequences of Table 7. Factor VII and VIIa have been cloned, as described in U.S. Pat. No. 6,806,063 and US Patent Application No. 20080261886.
In one aspect, the invention provides monomeric BPXTEN fusion proteins of FIX comprising the full-length sequence, or active fragments, or sequence variants, or any biologically active derivative of FIX, including the FIX sequences of Table 7, covalently linked to an XTEN, to create a chimeric molecule. In some cases, the fusion proteins comprising a coagulation factor such as FIX, further comprise one or more proteolytic cleavage site sequences. In another embodiment, the fusion protein comprises a first and a second, different cleavage sequence. In an embodiment of the foregoing, the cleavage sequence(s) are selected from Table 10. In those cases where the presence of the XTEN inhibits activation of FIX to the activated form of FIX (hereinafter “FIXa”) (e.g., wherein the XTEN is attached to the C-terminus of FIX), the one or more proteolytic cleavage site permits the release of the XTEN sequence when acted on by a protease, as described more fully below. In a feature of the foregoing, the intact FIX-XTEN composition serves as a pro-drug, and the release of the XTEN from the FIX-XTEN molecule by proteolysis permits the released FIX sequence to be converted to FIXa. In one embodiment, the one or more cleavage sequences can be a sequence having at least about 80% sequence identify to a sequence from Table 10, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99%, or 100% sequence identity to a sequence from Table 10.
FIX-XTEN fusion proteins can be designed in different configurations. In one embodiment, as illustrated in
In another embodiment, as illustrated in
In other cases, as illustrated in
In another embodiment, as illustrated in
In other embodiments, the FIX-XTEN can exist in the configuration (N- to C-terminal) XTEN-FIX, alternatively XTEN-FIX-XTEN, alternatively XTEN-CS-FIX, alternatively FIX-XTEN-FIX, alternatively FIX-CS-XTEN-CS-XTEN, or multimers of the foregoing.
In one embodiment, the FIX-XTEN is configured such that the FIX of the FIX-XTEN composition can be activated to FIXa by a coagulation protease without the release of some or all of an XTEN. In another embodiment, wherein FIX-XTEN comprises at least two XTEN, the FIX-XTEN is configured such that the FIX of the FIX-XTEN composition can be activated to FIXa by a coagulation protease without the release of one of the XTENs. In another embodiment, wherein the XTEN is to be released from the FIX-XTEN either prior to activation of the FIX to FIXa, or concomitant with the activation of the FIX to FIXa, the cleavage sequences are located sufficiently close to the ends of the XTEN linked to any portion of the FIX such that any remaining XTEN or cleavage sequence residues do not appreciably interfere with the activation of FIX, yet provide sufficient access to the protease to effect cleavage of the corresponding cleavage sequence. In one embodiment, wherein an XTEN is linked to the C-terminus of the FIX (as described above), the one or more cleavage sites can be located within about the first 100 amino acids of the N-terminus of the XTEN, more preferably within the first 80 amino acids, more preferably within the first 54 amino acids, more preferably within the first 42 amino acids, more preferably within the first 30 amino acids, more preferably within the first 18 amino acids, and most preferably within the first 6 amino acids of the N-terminus of the XTEN. In another embodiment, wherein an XTEN is linked internal to the FIX sequence (as described above), either between two FIX domains or within an external loop of a FIX domain or internal to a domain sequence, the XTEN can comprise two or more cleavage sequences in which at least one cleavage site can be located within about the first 100 amino acids of the N-terminus of the XTEN, within 80, within 54, within 42, within 30, within 18, or within 6 amino acids of the N-terminus and the XTEN can comprise at least a second cleavage site located within the last 100 amino acids of the C-terminus of the XTEN, within 80, within 54, within 42, within 30, within 18, or within 6 amino acids of the C-terminus of the XTEN.
In some cases, protease cleavage of the fusion protein releases the XTEN from the FIX sequence in a subject such that the FIX sequence can subsequently be activated. In other cases, protease cleavage of the fusion protein is a result of action of the proteases of the coagulation cascade, such that the XTEN is released concurrently with the processing and activation of FIX to FIXa. Thus, in a particular feature of some embodiments, the XTEN and associated cleavage site(s) of the FIX-XTEN fusion protein can be located such that the FIX sequence cannot be activated until XTEN is released from the fusion protein by proteolytic cleavage. In such embodiments, the FIX-XTEN can be used as prodrug that can be activated once it is administered to the subject. In one embodiment, the released FIX polypeptides can contain all or part of an XTEN, particularly when the FIX-XTEN comprises two XTEN sequences. Alternatively, the released FIX polypeptides can be free from the XTEN or substantially all of the XTEN.
In other embodiments, the cleavage site is used during the synthesis procedure of the fusion protein. For example, the fusion protein can further contain an affinity tag for isolation of the fusion protein after recombinant production. A protease that recognized the cleavage site in the fusion protein can remove the tag, while leaving a final product that is FIX linked to the XTEN.
Thus, the fusion protein can have a cleavage site, which can be cleaved before injection, after injection (in the blood circulation or tissues by proteases) and can be located such that the XTEN stays with the therapeutic product until it is released by an endogenous protease, either permitting the therapeutic product to be activated by the coagulation cascade, or the XTEN is released by a protease of the coagulation cascade.
In some embodiments, a fusion protein of FIX is converted from an inactive protein to an active protein (e.g., FIXa) by a site-specific protease, either in the circulation or within a body tissue or cavity. This cleavage may trigger an increase in potency of the pharmaceutically active domain (pro-drug activation) or it may enhance binding of the cleavage product to its target. So, for example, FIX-XTEN fusion proteins can be cleaved in the blood of a subject and the FIX sequence can become activated by the coagulation cascade or by another protease disclosed herein. The active form of the FIX fusion protein may or may not contain at least a fragment of XTEN. In a feature of the FIX-XTEN pro-drug embodiments, a higher dosage of the FIX-XTEN composition may be administered, compared to conventional FIX therapeutics, because the release of the FIX capable of being activated can be controlled by the selection of cleavage sequences, or varying the numbers of cleavage sites required to be cleaved before a form of FIX is released that can be activated. As those with skill in the art will appreciate, the sequence of any of the cleavage sites disclosed herein can be modified by introducing amino acid variations into the cleavage sequences in order to modify the kinetics of proteolytic cleavage, thereby affecting the kinetics of FIX release and subsequent activation.
The invention provides BPXTEN fusion proteins comprising a coagulation protein and XTEN. In some cases, the BPXTEN comprises a coagulation protein that exhibits at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a coagulation protein selected from Table 7. In one embodiment of the foregoing, the BPXTEN further comprises an XTEN sequence with at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to an XTEN selected from Table 2. In another embodiment, the BPXTEN comprises a sequence with at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a sequence selected from Table 43. The invention also contemplates substitution of any FIX sequence from Table 7, any XTEN from Table 2, and any cleavage sequence from Table 10 for the respective components of Table 43, or sequences with at least 90% sequence identity to the foregoing.
In another embodiment, the BPXTEN coagulation protein is the FVII sequence of Table 7 and the XTEN is selected from AE864 and AM875. In one embodiment of the foregoing, the BPXTEN comprises, in an N- to C-terminus configuration, FVII-AE864. In another embodiment, the BPXTEN is configured, N- to C-terminus as FVII-AM875. In another embodiment, the configured BPXTEN comprises a FVII that is at least about 70%, or 80%, or 90%, or at least about 95% or greater in the activated FVIIa form. In another embodiment, the BPXTEN comprising FVII and an XTEN can further comprise a cleavage sequence, which may include a sequence selected from Table 10.
(d) Growth Hormone Proteins
“Growth Hormone” or “GH” means the human growth hormone protein and species and sequence variants thereof, and includes, but is not limited to, the 191 single-chain amino acid human sequence of GH. Thus, GH can be the native, full-length protein or can be a truncated fragment or a sequence variant that retains at least a portion of the biological activity of the native protein. Effects of GH on the tissues of the body can generally be described as anabolic. Like most other protein hormones, GH acts by interacting with a specific plasma membrane receptor, referred to as growth hormone receptor. There are two known types of human GH (hereinafter “hGH”) derived from the pituitary gland: one having a molecular weight of about 22,000 daltons (22 kD hGH) and the other having a molecular weight of about 20,000 daltons (20 kD hGH). The 20 kD HGH has an amino acid sequence that corresponds to that of 22 kD hGH consisting of 191 amino acids except that 15 amino acid residues from the 32nd to the 46th of 22 kD hGH are missing. Some reports have shown that the 20 kD hGH has been found to exhibit lower risks and higher activity than 22 kD hGH. The invention also contemplates use of the 20 kD hGH as being appropriate for use as a biologically active polypeptide for BPXTEN compositions herein.
The invention contemplates inclusion in the BPXTEN of any GH homologous sequences, sequence fragments that are natural, such as from primates, mammals (including domestic animals), and non-natural sequence variants which retain at least a portion of the biologic activity or biological function of GH and/or that are useful for preventing, treating, mediating, or ameliorating a GH-related disease, deficiency, disorder or condition. Non-mammalian GH sequences are well-described in the literature. For example, a sequence alignment of fish GHs can be found in Genetics and Molecular Biology 2003 26 p. 295-300. An analysis of the evolution of avian GH sequences is presented in Journal of Evolutionary Biology 2006 19 p. 844-854. In addition, native sequences homologous to human GH may be found by standard homology searching techniques, such as NCBI BLAST.
In one embodiment, the GH incorporated into the subject compositions can be a recombinant polypeptide with a sequence corresponding to a protein found in nature. In another embodiment, the GH can be a sequence variant, fragment, homolog, or a mimetics of a natural sequence that retains at least a portion of the biological activity of the native GH. Table 8 provides a non-limiting list of sequences of GHs from a wide variety of mammalian species that are encompassed by the BPXTEN fusion proteins of the invention. Any of these GH sequences or homologous derivatives constructed by shuffling individual mutations between species or families may be useful for the fusion proteins of this invention. GH that can be incorporated into a BPXTEN fusion protein can include a protein that exhibits at least about 80% sequence identity, or alternatively 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100% sequence identity to a protein selected from Table 8.
IV). BPXTEN Structural Configurations and Properties
The BP of the subject compositions are not limited to native, full-length polypeptides, but also include recombinant versions as well as biologically and/or pharmacologically active variants or fragments thereof. For example, it will be appreciated that various amino acid substitutions can be made in the GP to create variants without departing from the spirit of the invention with respect to the biological activity or pharmacologic properties of the BP. Examples of conservative substitutions for amino acids in polypeptide sequences are shown in Table 9. However, in embodiments of the BPXTEN in which the sequence identity of the BP is less than 100% compared to a specific sequence disclosed herein, the invention contemplates substitution of any of the other 19 natural L-amino acids for a given amino acid residue of the given BP, which may be at any position within the sequence of the BP, including adjacent amino acid residues. If any one substitution results in an undesirable change in biological activity, then one of the alternative amino acids can be employed and the construct evaluated by the methods described herein, or using any of the techniques and guidelines for conservative and non-conservative mutations set forth, for instance, in U.S. Pat. No. 5,364,934, the contents of which is incorporated by reference in its entirety, or using methods generally known to those of skill in the art. In addition, variants can also include, for instance, polypeptides wherein one or more amino acid residues are added or deleted at the N- or C-terminus of the full-length native amino acid sequence of a BP that retains at least a portion of the biological activity of the native peptide.
(a) BPXTEN Fusion Protein Configurations
The invention provides BPXTEN fusion protein compositions comprising BP linked to one or more XTEN polypeptides useful for preventing, treating, mediating, or ameliorating a disease, disorder or condition related to glucose homeostasis, insulin resistance, or obesity. In some cases, the BPXTEN is a monomeric fusion protein with a BP linked to one or more XTEN polypeptides. In other cases, the BPXTEN composition can include two BP molecules linked to one or more XTEN polypeptides. The invention contemplates BPXTEN comprising, but not limited to BP selected from Tables 3-8 (or fragments or sequence variants thereof), and XTEN selected from Table 2 or sequence variants thereof. In some cases, at least a portion of the biological activity of the respective BP is retained by the intact BPXTEN. In other cases, the BP component either becomes biologically active or has an increase in activity upon its release from the XTEN by cleavage of an optional cleavage sequence incorporated within spacer sequences into the BPXTEN, described more fully below.
In one embodiment of the BPXTEN composition, the invention provides a fusion protein of formula I:
(BP)-(S)x-(XTEN) I
wherein independently for each occurrence, BP is a is a biologically active protein as described hereinabove; S is a spacer sequence having between 1 to about 50 amino acid residues that can optionally include a cleavage sequence (as described more fully below): x is either 0 or 1; and XTEN is an extended recombinant polypeptide as described hereinabove. The embodiment has particular utility where the BP requires a free N-terminus for desired biological activity, or where linking of the C-terminus of the BP to the fusion protein reduces biological activity and it is desired to reduce the biological activity and/or side effects of the administered BPXTEN.
In another embodiment of the BPXTEN composition, the invention provides a fusion protein of formula II (components as described above):
(XTEN)-(S)x-(BP) II
wherein independently for each occurrence, BP is a is a biologically active protein as described hereinabove; S is a spacer sequence having between 1 to about 50 amino acid residues that can optionally include a cleavage sequence (as described more fully below): x is either 0 or 1; and XTEN is an extended recombinant polypeptide as described hereinabove. The embodiment has particular utility where the BP requires a free C-terminus for desired biological activity, or where linking of the N-terminus of the BP to the fusion protein reduces biological activity and it is desired to reduce the biological activity and/or side effects of the administered BPXTEN.
Thus, the BPXTEN having a single BP and a single XTEN can have at least the following permutations of configurations, each listed in an N- to C-terminus orientation: BP-XTEN; XTEN-BP; BP-S-XTEN; or XTEN-S-BP.
In another embodiment, the invention provides an isolated fusion protein, wherein the fusion protein is of formula III:
(BP)-(S)x-(XTEN)-(S)y-(BP)-(S)z-(XTEN)z III
wherein independently for each occurrence, BP is a is a biologically active protein as described hereinabove: S is a spacer sequence having between 1 to about 50 amino acid residues that can optionally include a cleavage sequence (as described more fully below); x is either 0 or 1; y is either 0 or 1; z is either 0 or 1; and XTEN is an extended recombinant polypeptide as described hereinabove.
In another embodiment, the invention provides an isolated fusion protein, wherein the fusion protein is of formula IV (components as described above):
(XTEN)x-(S)y-(BP)-(S)z-(XTEN)-(BP) IV
In another embodiment, the invention provides an isolated fusion protein, wherein the fusion protein is of formula V (components as described above):
(BP)x-(S)x-(BP)-(S)y-(XTEN) V
In another embodiment, the invention provides an isolated fusion protein, wherein the fusion protein is of formula VI (components as described above):
(XTEN)-(S)x-(BP)-(S)y-(BP) VI
In another embodiment, the invention provides an isolated fusion protein, wherein the fusion protein is of formula VII (components as described above):
(XTEN)-(S)x-(BP)-(S)y-(BP)-(XTEN) VII
In the foregoing embodiments of fusion proteins of formulas I-VII, administration of a therapeutically effective dose of a fusion protein of an embodiment to a subject in need thereof can result in a gain in time of at least two-fold, or at least three-fold, or at least four-fold, or at least five-fold or more spent within a therapeutic window for the fusion protein compared to the corresponding BP not linked to the XTEN of and administered at a comparable dose to a subject.
Any spacer sequence group is optional in the fusion proteins encompassed by the invention. The spacer may be provided to enhance expression of the fusion protein from a host cell or to decrease steric hindrance such that the BP component may assume its desired tertiary structure and/or interact appropriately with its target molecule. For spacers and methods of identifying desirable spacers, see, for example, George, et al. (2003) Protein Engineering 15:871-879, specifically incorporated by reference herein. In one embodiment, the spacer comprises one or more peptide sequences that are between 1-50 amino acid residues in length, or about 1-25 residues, or about 1-10 residues in length. Spacer sequences, exclusive of cleavage sites, can comprise any of the 20 natural L amino acids, and will preferably comprise hydrophilic amino acids that are sterically unhindered that can include, but not be limited to, glycine (G), alanine (A), serine (S), threonine (T), glutamate (E) and proline (P). In some cases, the spacer can be polyglycines or polyalanines, or is predominately a mixture of combinations of glycine and alanine residues. The spacer polypeptide exclusive of a cleavage sequence is largely to substantially devoid of secondary structure. In one embodiment, one or both spacer sequences in a BPXTEN fusion protein composition may each further contain a cleavage sequence, which may be identical or may be different, wherein the cleavage sequence may be acted on by a protease to release the BP from the fusion protein.
In some cases, the incorporation of the cleavage sequence into the BPXTEN is designed to permit release of a BP that becomes active or more active upon its release from the XTEN. The cleavage sequences are located sufficiently close to the BP sequences, generally within 18, or within 12, or within 6, or within 2 amino acids of the BP sequence terminus, such that any remaining residues attached to the BP after cleavage do not appreciably interfere with the activity (e.g., such as binding to a receptor) of the BP, yet provide sufficient access to the prutease to be able to effect cleavage of the cleavage sequence. In some embodiments, the cleavage site is a sequence that can be cleaved by a protease endogenous to the mammalian subject such that the BPXTEN can be cleaved after administration to a subject. In such cases, the BPXTEN can serve as a prodrug or a circulating depot for the BP. Examples of cleavage sites contemplated by the invention include, but are not limited to, a polypeptide sequence cleavable by a mammalian endogenous protease selected from FXIa, FXIIa, kallikrein, FVIIa, FIXa, FXa, FIIa (thrombin), Elastase-2, granzyme B, MMP-12, MMP-13, MMP-17 or MMP-20, or by non-mammalian proteases such as TEV, enterokinase, PreScission™ protease (rhinovirus 3C protease), and sortase A. Sequences known to be cleaved by the foregoing proteases are known in the art. Exemplary cleavage sequences and cut sites within the sequences are presented in Table 10, as well as sequence variants. For example, thrombin (activated clotting factor II) acts on the sequence LTPRSLLV (SEQ ID NO: 222) [Rawlings N. D., et al. (2008) Nucleic Acids Res., 36: D320], which would be cut after the arginine at position 4 in the sequence. Active FIIa is produced by cleavage of FII by FXa in the presence of phospholipids and calcium and is down stream from factor IX in the coagulation pathway. Once activated its natural role in coagulation is to cleave fibrinogen, which then in turn, begins clot formation. FIIa activity is tightly controlled and only occurs when coagulation is necessary for proper hemostasis. However, as coagulation is an on-going process in mammals, by incorporation of the LTPRSLLV (SEQ ID NO: 223) sequence into the BPXTEN between the BP and the XTEN, the XTEN domain would be removed from the adjoining BP concurrent with activation of either the extrinsic or intrinsic coagulation pathways when coagulation is required physiologically, thereby releasing BP over time. Similarly, incorporation of other sequences into BPXTEN that are acted upon by endogenous proteases would provide for sustained release of BP that may, in certain cases, provide a higher degree of activity for the BP from the “prodrug” form of the BPXTEN.
In some cases, only the two or three amino acids flanking both sides of the cut site (four to six amino acids total) would be incorporated into the cleavage sequence. In other cases, the known cleavage sequence can have one or more deletions or insertions or one or two or three amino acid substitutions for any one or two or three amino acids in the known sequence, wherein the deletions, insertions or substitutions result in reduced or enhanced susceptibility but not an absence of susceptibility to the protease, resulting in an ability to tailor the rate of release of the BP from the XTEN. Exemplary substitutions are shown in Table 10.
In one embodiment, a BP incorporated into a BPXTEN fusion protein can have a sequence that exhibits at least about 80% sequence identity to a sequence from Tables 3-8, alternatively at least about 81%, or about 82%, or about 83%, or about 84%, or about 85%, or about 86%, or about 87%, or about 88%, or about 89%& or about 90%, or about 91%, or about 92%, or about 93%& or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99%, or about 100% sequence identity as compared with a sequence from Tables 3-8. The BP of the foregoing embodiment can be evaluated for activity using assays or measured or determined parameters as described herein, and those sequences that retain at least about 40%, or about 50%, or about 55%, or about 60%, or about 70%, or about 80%, or about 90%, or about 95% or more activity compared to the corresponding native BP sequence would be considered suitable for inclusion in the subject BPXTEN. The BP found to retain a suitable level of activity can be linked to one or more XTEN polypeptides described hereinabove. In one embodiment, a BP found to retain a suitable level of activity can be linked to one or more XTEN polypeptides having at least about 80% sequence identity to a sequence from Table 2, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity as compared with a sequence of Table 2, resulting in a chimeric fusion protein.
Non-limiting examples of sequences of fusion proteins containing a single BP linked to a single XTEN are presented in Table 40, 42, 43, and 44. In one embodiment, a BPXTEN composition would comprise a fusion protein having at least about 80% sequence identity to a BPXTEN from Tables 40, 42, 43, or 44, alternatively at least about 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or about 100% sequence identity as compared with a BPXTEN from Tables 40, 42, 43, or 44. Non-limiting examples of sequences of fusion proteins containing two molecules of the same BP linked to one or more XTEN are presented in Table 41, but the invention also contemplates substitution of other BP selected from Tables 3-8 linked to one or two XTEN, which may be the same or different, selected from Table 2. In the foregoing fusion proteins hereinabove described in this paragraph, the BPXTEN fusion protein can further comprise a cleavage sequence from Table 10; the cleavage sequence being located between the BP and the XTEN or between adjacent BP. In some cases, the BPXTEN comprising the cleavage sequences will also have one or more spacer sequence amino acids between the BP and the cleavage sequence or the XTEN and the cleavage sequence to facilitate access of the protease; the spacer amino acids comprising any natural amino acid, including glycine and alanine as preferred amino acids. Non-limiting examples of BPXTEN comprising BP, XTEN, cleavage sequence(s) and spacer amino acids are presented in Tables 42 and 43. However, the invention also contemplates substitution of any of the BP sequences of Tables 3-8 for a BP sequence of Tables 42 or 43, substitution of any XTEN sequence of Table 2 for an XTEN sequence of Tables 42 or 43, and substitution of any cleavage sequence of Table 10 for a cleavage sequence of Tables 42 or 43.
(b) Pharmacokinetic Properties of BPXTEN
The invention provides BPXTEN fusion proteins with enhanced pharmacokinetics compared to the BP not linked to XTEN that, when used at the dose determined for the composition by the methods described herein, can achieve a circulating concentration resulting in a pharmacologic effect, yet stay within the safety range for biologically active component of the composition for an extended period of time compared to a comparable dose of the BP not linked to XTEN. In such cases, the BPXTEN remains within the therapeutic window for the fusion protein composition for the extended period of time. As used herein, a “comparable dose” means a dose with an equivalent moles/kg for the active BP pharmacophore that is administered to a subject in a comparable fashion. It will be understood in the art that a “comparable dosage” of BPXTEN fusion protein would represent a greater weight of agent but would have essentially the same mole-equivalents of BP in the dose of the fusion protein and/or would have the same approximate molar concentration relative to the BP.
The pharmacokinetic properties of a BP that can be enhanced by linking a given XTEN to the BP include terminal half-life, area under the curve (AUC), Cmax volume of distribution, and bioavailability.
As described more fully in the Examples pertaining to pharmacokinetic characteristics of fusion proteins comprising XTEN, it was surprisingly discovered that increasing the length of the XTEN sequence could confer a disproportionate increase in the terminal half-life of a fusion protein comprising the XTEN. Accordingly, the invention provides BPXTEN fusion proteins comprising XTEN wherein the XTEN can be selected to provide a targeted half-life for the BPXTEN composition administered to a subject. In some embodiments, the invention provides monomeric fusion proteins comprising XTEN wherein the XTEN is selected to confer an increase in the terminal half-life for the administered BPXTEN, compared to the corresponding BP not linked to the fusion protein, of at least about two-fold longer, or at least about three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold, or at least about seven-fold, or at least about eight-fold, or at least about nine-fold, or at least about ten-fold, or at least about 15-fold, or at least a 20-fold or greater an increase in terminal half-life compared to the BP not linked to the fusion protein. Similarly, the BPXTEN fusion proteins can have an increase in AUC of at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or at least about 100%, or at least about 150%, or at least about 200%, or at least about 300% increase in AUC compared to the corresponding BP not linked to the fusion protein. The pharmacokinetic parameters of a BPXTEN can be determined by standard methods involving dosing, the taking of blood samples at times intervals, and the assaying of the protein using ELISA, HPLC, radioassay, or other methods known in the art or as described herein, followed by standard calculations of the data to derive the half-life and other PK parameters.
The invention further provides BPXTEN comprising a first and a second BP molecule, optionally separated by a spacer sequence that may further comprise a cleavage sequence, or separated by a second XTEN sequence. In one embodiment, the BP has less activity when linked to the fusion protein compared to a corresponding BP not linked to the fusion protein. In such case, as illustrated in
(c) Pharmacology and Pharmaceutical Properties of BPXTEN
The present invention provides BPXTEN compositions comprising BP covalently linked to XTEN that can have enhanced properties compared to BP not linked to XTEN, as well as methods to enhance the therapeutic and/or biologic activity or effect of the respective two BP components of the compositions. In addition, the invention provides BPXTEN compositions with enhanced properties compared to those art-known fusion proteins containing immunoglobulin polypeptide partners, polypeptides of shorter length and/or polypeptide partners with repetitive sequences. In addition, BPXTEN fusion proteins provide significant advantages over chemical conjugates, such as pegylated constructs, notably the fact that recombinant BPXTEN fusion proteins can be made in bacterial cell expression systems, which can reduce time and cost at both the research and development and manufacturing stages of a product, as well as result in a more homogeneous, defined product with less toxicity for both the product and metabolites of the BPXTEN compared to pegylated conjugates.
As therapeutic agents, the BPXTEN may possess a number of advantages over therapeutics not comprising XTEN including, for example, increased solubility, increased thermal stability, reduced immunogenicity, increased apparent molecular weight, reduced renal clearance, reduced proteolysis, reduced metabolism, enhanced therapeutic efficiency, a lower effective therapeutic dose, increased bioavailability, increased time between dosages to maintain blood levels within the therapeutic window for the BP, a “tailored” rate of absorption, enhanced lyophilization stability, enhanced serum/plasma stability, increased terminal half-life, increased solubility in blood stream, decreased binding by neutralizing antibodies, decreased receptor-mediated clearance, reduced side effects, retention of receptor/ligand binding affinity or receptor/ligand activation, stability to degradation, stability to freeze-thaw, stability to proteases, stability to ubiquitination, ease of administration, compatibility with other pharmaceutical excipients or carriers, persistence in the subject, increased stability in storage (e.g., increased shelf-life), reduced toxicity in an organism or environment and the like. The net effect of the enhanced properties is that the BPXTEN may result in enhanced therapeutic and/or biologic effect when administered to a subject with a metabolic disease or disorder.
In other cases where, where enhancement of the pharmaceutical or physicochemical properties of the BP is desirable, (such as the degree of aqueous solubility or stability), the length and/or the motif family composition of the first and the second XTEN sequences of the first and the second fusion protein may each be selected to confer a different degree of solubility and/or stability on the respective fusion proteins such that the overall pharmaceutical properties of the BPXTEN composition are enhanced. The BPXTEN fusion proteins can be constructed and assayed, using methods described herein, to confirm the physicochemical properties and the XTEN adjusted, as needed, to result in the desired properties. In one embodiment, the XTEN sequence of the BPXTEN is selected such that the fusion protein has an aqueous solubility that is within at least about 25% greater compared to a BP not linked to the fusion protein, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 75%, or at least about 100%, or at least about 200%, or at least about 300%, or at least about 400%, or at least about 500%, or at least about 1000% greater than the corresponding BP not linked to the fusion protein. In the embodiments hereinabove described in this paragraph, the XTEN of the fusion proteins can have at least about 80% sequence identity, or about 90%, or about 91%, or about 92%, or about 93%, or about 94%, or about 95%, or about 96%, or about 97%, or about 98%, or about 99%, to about 100% sequence identity to an XTEN selected from Table 2.
In one embodiment, the invention provides BPXTEN compositions that can maintain the BP component within a therapeutic window for a greater period of time compared to comparable dosages of the corresponding BP not linked to XTEN. It will be understood in the art that a “comparable dosage” of BPXTEN fusion protein would represent a greater weight of agent but would have the same approximate mole-equivalents of BP in the dose of the fusion protein and/or would have the same approximate molar concentration relative to the BP.
The invention also provides methods to select the XTEN appropriate for conjugation to provide the desired pharmacokinetic properties that, when matched with the selection of dose, enable increased efficacy of the administered composition by maintaining the circulating concentrations of the BP within the therapeutic window for an enhanced period of time. As used herein, “therapeutic window” means that amount of drug or biologic as a blood or plasma concentration range, that provides efficacy or a desired pharmacologic effect over time for the disease or condition without unacceptable toxicity; the range of the circulating blood concentrations between the minimal amount to achieve any positive therapeutic effect and the maximum amount which results in a response that is the response immediately before toxicity to the subject (at a higher dose or concentration). Additionally, therapeutic window generally encompasses an aspect of time; the maximum and minimum concentration that results in a desired pharmacologic effect over time that does not result in unacceptable toxicity or adverse events. A dosed composition that stays within the therapeutic window for the subject could also be said to be within the “safety range.”
Dose optimization is important for all drugs, especially for those with a narrow therapeutic window. For example, many peptides involved in glucose homeostasis have a narrow therapeutic window. For a BP with a narrow therapeutic window, such as glucagon or a glucagon analog, a standardized single dose for all patients presenting with a variety of symptoms may not always be effective. Since different glucose regulating peptides are often used together in the treatment of diabetic subjects, the potency of each and the interactive effects achieved by combining and dosing them together must also be taken into account. A consideration of these factors is well within the purview of the ordinarily skilled clinician for the purpose of determining the therapeutically or pharmacologically effective amount of the BPXTEN, versus that amount that would result in unacceptable toxicity and place it outside of the safety range.
In many cases, the therapeutic window for the BP components of the subject compositions have been established and are available in published literature or are stated on the drug label for approved products containing the BP. In other cases, the therapeutic window can be established. The methods for establishing the therapeutic window for a given composition are known to those of skill in the art (see, e.g., Goodman & Gilman's The Pharmacological Basis of Therapeutics, 11th Edition, McGraw-Hill (2005)). For example, by using dose-escalation studies in subjects with the target disease or disorder to determine efficacy or a desirable pharmacologic effect, appearance of adverse events, and determination of circulating blood levels, the therapeutic window for a given subject or population of subjects can be determined for a given drug or biologic, or combinations of biologics or drugs. The dose escalation studies can evaluate the activity of a BPXTEN through metabolic studies in a subject or group of subjects that monitor physiological or biochemical parameters, as known in the art or as described herein for one or more parameters associated with the metabolic disease or disorder, or clinical parameters associated with a beneficial outcome for the particular indication, together with observations and/or measured parameters to determine the no effect dose, adverse events, maximum tolerated dose and the like, together with measurement of pharmacokinetic parameters that establish the determined or derived circulating blood levels. The results can then be correlated with the dose administered and the blood concentrations of the therapeutic that are coincident with the foregoing determined parameters or effect levels. By these methods, a range of doses and blood concentrations can be correlated to the minimum effective dose as well as the maximum dose and blood concentration at which a desired effect occurs and above which toxicity occurs, thereby establishing the therapeutic window for the dosed therapeutic. Blood concentrations of the fusion protein (or as measured by the BP component) above the maximum would be considered outside the therapeutic window or safety range. Thus, by the foregoing methods, a Cmin blood level would be established, below which the BPXTEN fusion protein would not have the desired pharmacologic effect, and a Cmax blood level would be established that would represent the highest circulating concentration before reaching a concentration that would elicit unacceptable side effects, toxicity or adverse events, placing it outside the safety range for the BPXTEN. With such concentrations established, the frequency of dosing and the dosage can be further refined by measurement of the Cmax and Cmin to provide the appropriate dose and dose frequency to keep the fusion protein(s) within the therapeutic window. One of skill in the art can, by the means disclosed herein or by other methods known in the art, confirm that the administered BPXTEN remains in the therapeutic window for the desired interval or requires adjustment in dose or length or sequence of XTEN. Further, the determination of the appropriate dose and dose frequency to keep the BPXTEN within the therapeutic window establishes the therapeutically effective dose regimen; the schedule for administration of multiple consecutive doses using a therapeutically effective dose of the fusion protein to a subject in need thereof resulting in consecutive Cmax peaks and/or Cmin troughs that remain within the therapeutic window and results in an improvement in at least one measured parameter relevant for the target disease, disorder or condition. In some cases, the BPXTEN administered at an appropriate dose to a subject may result in blood concentrations of the BPXTEN fusion protein that remains within the therapeutic window for a period at least about two-fold longer compared to the corresponding BP not linked to XTEN and administered at a comparable dose; alternatively at least about three-fold longer; alternatively at least about four-fold longer: alternatively at least about five-fold longer; alternatively at least about six-fold longer; alternatively at least about seven-fold longer; alternatively at least about eight-fold longer; alternatively at least about nine-fold longer or at least about ten-fold longer or greater compared to the corresponding BP not linked to XTEN and administered at a comparable dose. As used herein, an “appropriate dose” means a dose of a drug or biologic that, when administered to a subject, would result in a desirable therapeutic or pharmacologic effect and a blood concentration within the therapeutic window.
In one embodiment, the BPXTEN administered at a therapeutically effective dose regimen results in a gain in time of at least about three-fold longer; alternatively at least about four-fold longer; alternatively at least about five-fold longer; alternatively at least about six-fold longer; alternatively at least about seven-fold longer; alternatively at least about eight-fold longer; alternatively at least about nine-fold longer or at least about ten-fold longer between at least two consecutive Cmax peaks and/or Cmin troughs for blood levels of the fusion protein compared to the corresponding biologically active protein of the fusion protein not linked to the fusion protein and administered at a comparable dose regimen to a subject. In another embodiment, the BPXTEN administered at a therapeutically effective dose regimen results in a comparable improvement in one, or two, or three or more measured parameter using less frequent dosing or a lower total dosage in moles of the fusion protein of the pharmaceutical composition compared to the corresponding biologically active protein component(s) not linked to the fusion protein and administered to a subject using a therapeutically effective dose regimen for the BP. The measured parameters may include any of the clinical, biochemical, or physiological parameters disclosed herein, or others known in the art for assessing subjects with glucose- or insulin-related disorders, metabolic diseases or disorders, coagulation or bleeding disorders, or growth hormone-related disorders.
The activity of the BPXTEN compositions of the invention, including functional characteristics or biologic and pharmacologic activity and parameters that result, may be determined by any suitable screening assay known in the art for measuring the desired characteristic. The activity and structure of the BPXTEN polypeptides comprising BP components may be measured by assays described herein; e.g., one or more assays selected from Table 39, assays of the Examples, or by methods known in the art to ascertain the degree of solubility, structure and retention of biologic activity. Assays can be conducted that allow determination of binding characteristics of the BPXTEN for BP receptors or a ligand, including binding constant (Kd), EC50 values, as well as their half-life of dissociation of the ligand-receptor complex (T1/2). Binding affinity can be measured, for example, by a competition-type binding assay that detects changes in the ability to specifically bind to a receptor or ligand. Additionally, techniques such as flow cytometry or surface plasmon resonance can be used to detect binding events. The assays may comprise soluble receptor molecules, or may determine the binding to cell-expressed receptors. Such assays may include cell-based assays, including assays for proliferation, cell death, apoptosis and cell migration. Other possible assays may determine receptor binding of expressed polypeptides, wherein the assay may comprise soluble receptor molecules, or may determine the binding to cell-expressed receptors. The binding affinity of a BPXTEN for the target receptors or ligands of the corresponding BP can be assayed using binding or competitive binding assays, such as Biacore assays with chip-bound receptors or binding proteins or ELISA assays, as described in U.S. Pat. No. 5,534,617, assays described in the Examples herein, radio-receptor assays, or other assays known in the art. In addition, BP sequence variants (assayed as single components or as BPXTEN fusion proteins) can be compared to the native BP using a competitive ELISA binding assay to determine whether they have the same binding specificity and affinity as the native BP, or some fraction thereof such that they are suitable for inclusion in BPXTEN.
The invention provides isolated BPXTEN in which the binding affinity for BP target receptors or ligands by the BPXTEN can be at least about 10%, or at least about 20%, or at least about 30%, or at least about 40%, or at least about 50%, or at least about 60%, or at least about 70%, or at least about 80%, or at least about 90%, or at least about 95%, or at least about 990%, or at least about 100% or more of the affinity of a native BP not bound to XTEN for the target receptor or ligand. In some cases, the binding affinity Kd between the subject BPXTEN and a native receptor or ligand of the BPXTEN is at least about 10−4 M, alternatively at least about 10−5 M, alternatively at least about 10−6 M. or at least about 10−7 M of the affinity between the BPXTEN and a native receptor or ligand.
In other cases, the invention provides isolated BPXTEN in which the fusion protein is designed to bind with high affinity to a target receptor, thereby resulting in antagonistic activity for the native ligand. A non-limiting example of such a BPXTEN is IL-1raXTEN, which is configured to bind to an IL-1 receptor such that the bound composition substantially interferes with the binding of IL-1 α and/or IL-1β to IL-1 receptor. In certain cases, the interference by an antagonist BPXTEN (such as, but not limited to IL-1raXTEN) with the binding the native ligand to the target receptor can be at least about 1%, or about 10° %, or about 20%, or about 30%, or about 40%, or about 50%, or about 60%, or about 70%, or about 80%, or about 90%, or about 95%, or about 99%, or about 100%. In other embodiments, the invention provides isolated BPXTEN fusion proteins (such as, but not limited to IL-1raXTEN) wherein the binding of the isolated fusion protein to a cellular receptor elicits less than 20%, or less than 10%, or less than 5% activation of the signaling pathways of the cell with bound BPXTEN antagonist in comparison to those evoked by the native ligand. In other cases, the antagonistic BPXTEN compositions bind to the target receptor with a dissociation constant of about 10 nM or less, about 5 nM or less, about 1 nM or less, about 500 pM or less, about 250 pM or less, about 100 pM or less, about 50 pM or less, or about 25 pM or less. Non-limiting examples of specific constructs of antagonistic BPXTEN can include IL-1ra-AM875, IL-1ra-AE864, or IL-1ra-AM1296.
In some cases, the BPXTEN fusion proteins of the invention retain at least about 10%, or about 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 98%, or 99% percent of the biological activity of the corresponding BP not linked to the fusion protein with regard to an in vitro biologic activity or pharmacologic effect known or associated with the use of the native BP in the treatment and prevention of metabolic conditions and disorders. In some cases of the foregoing embodiment, the activity of the BP component may be manifest by the intact BPXTEN fusion protein, while in other cases the activity of the BP component would be primarily manifested upon cleavage and release of the BP from the fusion protein by action of a protease that acts on a cleavage sequence incorporated into the BPXTEN fusion protein. In the foregoing, as illustrated in
In other cases, the BPXTEN are designed to reduce the binding affinity of the BP component when linked to the XTEN to, for example, increase the terminal half-life of BPXTEN administered to a subject by reducing receptor-mediated clearance or to reduce toxicity or side effects due to the administered composition. Where the toxicological no-effect dose or blood concentration of a BP not linked to an XTEN is low (meaning that the native peptide has a high potential to result in side effects), the invention provides BPXTEN fusion proteins in which the fusion protein is configured to reduce the biologic potency or activity of the BP component.
In some cases, it has been found that a BPXTEN can be configured to have a substantially reduced binding affinity (expressed as Kd) and a corresponding reduced bioactivity, compared to the activity of a BPXTEN wherein the configuration does not result in reduced binding affinity of the corresponding BP component, and that such configuration is advantageous in terms of having a composition that displays both a long terminal half-life and retains a sufficient degree of bioactivity. In one example, it has been found that while linking a single XTEN to the C-terminus of glucagon results in the retention of significant binding affinity to its target receptor (see Example 31), linking an XTEN to the N-terminus decreases its binding affinity and corresponding biological activity, compared to constructs where the XTEN is bound to the C-terminus. In another example, it has been found, as described in the Examples, that while linking of human growth hormone (hGH) to the C-terminus of an XTEN molecule does not substantially interfere with the binding to hGH receptors, the addition of a second XTEN to the C-terminus of the same molecule (placing the second XTEN to the C-terminus of hGH) reduced the affinity of the molecule to the hGH receptor and also resulted in an increase in terminal half-life of the XTEN-hGH-XTEN configuration compared to XTEN-hGH configuration. The ability to reduce binding affinity of the BP to its target receptor may be dependent on the requirement to have a free N- or C-terminus for the particular BP. Accordingly, the invention provides a method for increasing the terminal half-life of a BPXTEN by producing a single-chain fusion protein construct with a specific N- to C-terminus configuration of the components comprising at least a first biologically active protein and one or more XTEN, wherein the fusion protein in a first N- to C-terminus configuration of the biologically active protein and XTEN components has reduced receptor-mediated clearance (RMC) and a corresponding increase in terminal half-life compared to a BPXTEN in a second N- to C-terminus configuration. In one embodiment of the foregoing, the BPXTEN is configured, N- to C-terminus as BP-XTEN. In another embodiment of the foregoing, the BPXTEN is configured XTEN-BP. In another embodiment of the foregoing, the BPXTEN is configured XTEN-BP-XTEN. In the latter embodiment, the two XTEN molecules can be identical or they can be of a different sequence composition or length. Non-limiting examples of the foregoing embodiment with two XTEN linked to a single BP include the constructs AE921-hGH-AE144 (SEQ ID NO: 1817), AE921-hGH-AE288 (SEQ ID NO: 1818, AE864-hGH-AE144, AM875-hGH-AE144, and AM875-hGH-AE288. Non-limiting examples of the foregoing embodiment with one BP linked to one XTEN include AE144-glucagon (SEQ ID NO: 827). AE288-glucagon (SEQ ID NO: 828), AD576-glucagon (SEQ ID NO: 831), AM923-glucagon (SEQ ID NO: 840), Y72-glucagon (SEQ ID NO: 823), AM875-IL-1ra or AE864-IL-1ra. The invention contemplates other such constructs in which a BP from Tables 3-8 and XTEN from Table 2 are substituted for the respective components of the foregoing examples, and configured such that the construct has reduced receptor mediated clearance compared to an alternate configuration of the respective components.
In some cases, the method provides configured BPXTEN in which the reduced receptor mediated clearance can result in an increase in the terminal half-life of at least two-fold, or at least three-fold, or at least four-fold, or at least five-fold compared to the half-life of a BPXTEN in a second configuration where RMC is not reduced. The invention takes advantage of BP ligands wherein reduced binding affinity to a receptor, either as a result of a decreased on-rate or an increased off-rate, may be effected by the obstruction of either the N- or C-terminus, and using that terminus as the linkage to another polypeptide of the composition, whether another BP, an XTEN, or a spacer sequence. The choice of the particular configuration of the BPXTEN fusion protein can reduce the degree of binding affinity to the receptor such that a reduced rate of receptor-mediated clearance can be achieved. Generally, activation of the receptor is coupled to RMC such that binding of a polypeptide to its receptor without activation does not lead to RMC, while activation of the receptor leads to RMC. However, in some cases, particularly where the ligand has an increased off rate, the ligand may nevertheless be able to bind sufficiently to initiate cell signaling without triggering receptor mediated clearance, with the net result that the BPXTEN remains bioavailable. In such cases, the configured BPXTEN has an increased half-life compared to those configurations that lead to a higher degree of RMC.
In cases where a reduction in binding affinity is desired in order to reduce receptor-mediated clearance but retention of at least a portion of the biological activity is desired, it will be clear that sufficient binding affinity to obtain the desired receptor activation must nevertheless be maintained. Thus, in one embodiment, the invention provides a BPXTEN configured such that the binding affinity of the BPXTEN for a target receptor is in the range of about 0.01%-40%, or about 0.1%-30%, or about 1%-20% of the binding affinity compared to a corresponding BPXTEN in a configuration wherein the binding affinity is not reduced. The binding affinity of the configured BXTEN is thus preferably reduced by at least about 80%, or at least about 85%, or at least about 90%, or at least about 95%, or at least about 99%, or at least about 99.9%, or at least about 99.99% as compared to the binding affinity of a corresponding BPXTEN in a configuration wherein the binding affinity of the BP component to the target receptor is not reduced or compared to the BP not linked to the fusion protein, determined under comparable conditions. Expressed differently, the BP component of the configured BPXTEN may have a binding affinity that is as small as about 0.01%, or at least about 0.1%, or at least about 1%, or at least about 2%, or at least about 3%, or at least about 4%, or at least about 5%, or at least about 10%, or at least about 20% of that of the corresponding BP component of a BPXTEN in a configuration wherein the binding affinity of the BP component is not reduced. In the foregoing embodiments hereinabove described in this paragraph, the binding affinity of the configured BPXTEN for the target receptor would be “substantially reduced” compared to a corresponding native BP or a BPXTEN with a configuration in which the binding affinity of the corresponding BP component is not reduced. Accordingly, the present invention provides compositions and methods to produce compositions with reduced RMC by configuring the BPXTEN so as to be able to bind and activate a sufficient number of receptors to obtain a desired in vivo biological response yet avoid activation of more receptors than is required for obtaining such response. In one embodiment, the BPXTEN is configured such that the subject BP is at the N-terminus of the BPXTEN, wherein the RMC of the administered BPXTEN is reduced compared to a BPXTEN configured with the subject BP linked to the C-terminus of an XTEN and at least a portion of the biological activity of the native BP is retained. In another embodiment, the BPXTEN is configured such that the subject BP is at the C-terminus of the BPXTEN, wherein the RMC of the administered BPXTEN is reduced compared to a BPXTEN configured with the subject BP is at the N-terminus of the BPXTEN and at least a portion of the biological activity of the native BP is retained. In another embodiment, the BPXTEN is configured, N- to C-terminus, as XTEN-BP-XTEN, wherein the RMC of the administered BPXTEN is reduced compared to a BPXTEN configured with one XTEN and at least a portion of the biological activity of the native BP is retained. It will be apparent to one of skill in the art that other configurations to achieve this property are contemplated by the invention; e.g., addition of a second molecule of the BP or a spacer sequence. In the foregoing embodiments hereinabove described in this paragraph, the half-life of the BPXTEN can be increased at least about 50%, or at least about 75%, or at least about 100%, or at least about 150%, or at least about 200%, or at least about 300% compared to a BPXTEN configured wherein the binding affinity and RMC of the BP component is not reduced. In the foregoing embodiments hereinabove described in this paragraph, the increased half-life can permit higher dosages and reduced frequency of dosing compared to BP not linked to XTEN or compared to BPXTEN configurations wherein the BP component retains a binding affinity to the receptor comparable to the native BP.
Specific in vivo and ex vivo biological assays may also be used to assess the biological activity of each configured BPXTEN and/or BP component to be incorporated into BPXTEN. For example, the increase of insulin secretion and/or transcription from the pancreatic beta cells can be measured by methods known in the art. Glucose uptake by tissues can also be assessed by methods such as the glucose clamp assay and the like. Other in vivo and ex vivo parameters suitable to assess the activity of administered BPXTEN fusion proteins in treatment of metabolic diseases and disorders include fasting glucose level, peak postprandial glucose level, glucose homeostasis, response to oral glucose tolerance test, response to insulin challenge. HA1c, caloric intake, satiety, rate of gastric emptying, pancreatic secretion, insulin secretion, peripheral tissue insulin sensitivity, beta cell mass, beta cell destruction, blood lipid levels or profiles, body mass index, or body weight. Based on the results of these assays or other assays known in the art, the BPXTEN configuration or composition can be confirmed or, if needed, adjusted and re-assayed to confirm the target binding affinity or biologic activity.
Specific assays and methods for measuring the physical and structural properties of expressed proteins are known in the art, including methods for determining properties such as protein aggregation, solubility, secondary and tertiary structure, melting properties, contamination and water content, etc. Such methods include analytical centrifugation, EPR, HPLC-ion exchange, HPLC-size exclusion, HPLC-reverse phase, light scattering, capillary electrophoresis, circular dichroism, differential scanning calorimetry, fluorescence, HPLC-ion exchange, HPLC-size exclusion, IR, NMR, Raman spectroscopy, refractometry, and UV/Visible spectroscopy. Additional methods are disclosed in Arnau et al, Prot Expr and Purif (2006) 48, 1-13. Application of these methods to the invention would be within the grasp of a person skilled in the art.
V). Uses of the Compositions of the Present Invention
In another aspect, the invention provides a method of for achieving a beneficial effect in a disease, disorder or condition mediated by BP. The present invention addresses disadvantages and/or limitations of BP that have a relatively short terminal half-life and/or a narrow therapeutic window between the minimum effective dose and the maximum tolerated dose.
In one embodiment, the invention provides a method for achieving a beneficial affect in a subject comprising the step of administering to the subject a therapeutically- or prophylactically-effective amount of a BPXTEN. The effective amount can produce a beneficial effect in helping to treat a disease or disorder. In some cases, the method for achieving a beneficial effect can include administering a therapeutically effective amount of a BPXTEN fusion protein composition to treat a subject with a glucose-related or metabolic disease, disorder, or condition, including, but not limited to, Type 1 diabetes, Type 2 diabetes, Syndrome X, insulin resistance, hyperinsulinemia, atherosclerosis, diabetic neuropathy, dyslipidemia, obesity, eating disorders, gestational diabetes, hypercholesterolemia, hypertension, insufficient pancreatic beta cell mass, pulmonary hypertension, or retinal neurodegenerative processes. Other examples of glucose-related or metabolic diseases or clinical disorders that may benefit from treatment with the BPXTEN compositions of the present invention include, but are not limited to, the “honeymoon period” of Type I diabetes, juvenile diabetes, excessive appetite, insufficient satiety, metabolic disorder, glucagonomas, Crohn's disease, ulcerative colitis, renal failure, congestive heart failure, nephrotic syndrome, disorders wherein the reduction of food intake is desired, post-surgical catabolic changes, hibernating myocardium or diabetic cardiomyopathy, insufficient urinary sodium excretion, excessive urinary potassium concentration, conditions or disorders associated with toxic hypervolemia, polycystic ovary syndrome, nephropathy, gastrointestinal disorders such as diarrhea, postoperative dumping syndrome, irritable bowel syndrome, critical illness polyneuropathy (CIPN), systemic inflammatory response syndrome (SIRS), dyslipidemia, stroke, reperfusion injury following ischemia, and coronary heart disease risk factor (CHDRF) syndrome, or disorders wherein the reduction of food intake is desired.
In some cases, the method for achieving a beneficial effect can include administering a therapeutically effective amount of a BPXTEN fusion protein composition to treat a subject with a coagulation protein deficiency or a bleeding disorder, including but not limited to Factor VII deficiency, Factor X deficiency, Factor XII deficiency, hemophilia A, hemophilia B (Christmas Disease), hemophilia C, idiopathic thrombocytopenic purpura (ITP). Von Willebrand's disease (type I and type II), trauma-associated bleeding, or surgical bleeding.
In other cases, the method for achieving a beneficial effect can include administering a therapeutically effective amount of a BPXTEN fusion protein composition to treat a subject with a growth-hormone related disorder or condition that can include, but not be limited to, GH deficiency in adults and children, Turner's Syndrome, Prader-Willi Syndrome, chronic renal failure, intrauterine growth retardation, idiopathic short stature, AIDS wasting, obesity, multiple sclerosis, aging, fibromyalgia, Crohn's disease, ulcerative colitis, muscular dystrophy or low muscle mass (e.g. bodybuilding), low bone density, or any other indication for which GH is utilized.
In one embodiment, the method comprises administering a therapeutically-effective amount of a pharmaceutical composition comprising a BPXTEN fusion protein composition comprising a BP linked to an XTEN sequence(s) and at least one pharmaceutically acceptable carrier to a subject in need thereof that results in greater improvement in at least one parameter, physiologic condition, or clinical outcome mediated by the BP component(s) compared to the effect mediated by administration of a pharmaceutical composition comprising a BP not linked to XTEN and administered at a comparable dose. In one embodiment, the pharmaceutical composition is administered at a therapeutically effective dose. In another embodiment, the pharmaceutical composition is administered using multiple consecutive doses using a therapeutically effective dose regimen (as defined herein) for the length of the dosing period.
As a result of the enhanced PK parameters of BPXTEN, as described herein, the BP may be administered using longer intervals between doses compared to the corresponding BP not linked to XTEN to prevent, treat, alleviate, reverse or ameliorate symptoms or clinical abnormalities of the metabolic disease, disorder or condition or prolong the survival of the subject being treated.
The methods of the invention may include administration of consecutive doses of a therapeutically effective amount of the BPXTEN for a period of time sufficient to achieve and/or maintain the desired parameter or clinical effect, and such consecutive doses of a therapeutically effective amount establishes the therapeutically effective dose regimen for the BPXTEN; i.e., the schedule for consecutively administered doses of the fusion protein composition, wherein the doses are given in therapeutically effective amounts to result in a sustained beneficial effect on any clinical sign or symptom, aspect, measured parameter or characteristic of a metabolic disease state or condition, including, but not limited to, those described herein.
A therapeutically effective amount of the BPXTEN may vary according to factors such as the disease state, age, sex, and weight of the individual, and the ability of the antibody or antibody portion to elicit a desired response in the individual. A therapeutically effective amount is also one in which any toxic or detrimental effects of the BPXTEN are outweighed by the therapeutically beneficial effects. A prophylactically effective amount refers to an amount of BPXTEN required for the period of time necessary to achieve the desired prophylactic result.
For the inventive methods, longer acting BPXTEN compositions are preferred, so as to improve patient convenience, to increase the interval between doses and to reduce the amount of drug required to achieve a sustained effect. In one embodiment, a method of treatment comprises administration of a therapeutically effective dose of a BPXTEN to a subject in need thereof that results in a gain in time spent within a therapeutic window established for the fusion protein of the composition compared to the corresponding BP component(s) not linked to the fusion protein and administered at a comparable dose to a subject. In some cases, the gain in time spent within the therapeutic window is at least about three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold, or at least about eight-fold, or at least about 10-fold, or at least about 20-fold, or at least about 40-fold compared to the corresponding BP component not linked to the fusion protein and administered at a comparable dose to a subject. The methods further provide that administration of multiple consecutive doses of a BPXTEN administered using a therapeutically effective dose regimen to a subject in need thereof can result in a gain in time between consecutive Cmax peaks and/or Cmin troughs for blood levels of the fusion protein compared to the corresponding BP(s) not linked to the fusion protein and administered using a dose regimen established for that BP. In the foregoing embodiment, the gain in time spent between consecutive Cmax peaks and/or Cmin troughs can be at least about three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold, or at least about eight-fold, or at least about 10-fold, or at least about 20-fold, or at least about 40-fold compared to the corresponding BP component(s) not linked to the fusion protein and administered using a dose regimen established for that BP. In the embodiments hereinabove described in this paragraph the administration of the fusion protein can result in an improvement in at least one of the parameters (disclosed herein as being useful for assessing the subject diseases, conditions or disorders) using a lower unit dose in moles of fusion protein compared to the corresponding BP component(s) not linked to the fusion protein and administered at a comparable unit dose or dose regimen to a subject.
In one embodiment, the BPXTEN can have activity that results in an improvement in one of the clinical, biochemical or physiologic parameters that is greater than the activity of the BP component not linked to XTEN, determined using the same assay or based on a measured clinical parameter. In another embodiment, the BPXTEN can have activity in two or more clinical or metabolic-related parameters (e.g., glucose homeostasis and weight control in a diabetic subject, or reduced prothrombin and bleeding times in a hemophiliac subject, or increased muscle mass and bone density in a growth-hormone deficient subject), each mediated by one of the different BP that collectively result in an enhanced effect compared the BP component not linked to XTEN, determined using the same assays or based on measured clinical parameters. In another embodiment, administration of the BPXTEN can result in activity in one or more of the clinical or biochemical or physiologic parameters that is of longer duration than the activity of one of the single BP components not linked to XTEN, determined using that same assay or based on a measured clinical parameter.
In one embodiment, the method of treatment comprises administration of a BPXTEN using a therapeutically effective dose regimen to effect improvements in one or more parameters associated with diabetes or insulin resistance. In the foregoing embodiment, the improvements may be assessed by a primary efficacy or clinical endpoint, for example an improvement in hemoglobin A1c (HbA1c, see for example Reynolds et al., BMJ, 333(7568):586-589, 2006). Improvements in HbA1c that are indicative of therapeutic efficacy may vary depending on the initial baseline measurement in a patient, with a larger decrease often corresponding to a higher initial baseline and a smaller decrease often corresponding to a lower initial baseline. In some embodiments, the method can result in an HbA1c decrease of at least about 0.5%, or alternatively at least about 1%, or alternatively at least about 1.5%, or alternatively at least about 2%, or alternatively at least about 2.5%, or alternatively at least about 3%, or alternatively at least about 3.5%, or at least about 4% or more compared with pre-dose levels. In other embodiments, the method of treatment can result in fasting blood sugar (e.g., glucose) levels to less than 130 mg/dL, alternatively less than 125 mg/dL, alternatively less than 120 mg/dL, alternatively less than 115 mg/dL, alternatively less than 110 mg/dL, alternatively less than 105 mg/dL, or fasting blood sugar levels less than 100 mg/dL. In other embodiments, the method can result in reductions in fasting blood sugar (e.g., glucose) levels of greater than about 20%, more preferably greater than about 30%, more preferably greater than about 40%, more preferably greater than about 50%, more preferably greater than about 60%, more preferably greater than about 70%, more preferably greater than about 80%, and most preferably greater than about 90% compared to pre-dose levels. In other embodiments, the method can result in 120 minute oral glucose tolerance test (OGTT) glucose levels of less than about 200 mg/dL, more preferably less than about 190 mg/dL, more preferably less than about 180 mg/dL, more preferably less than about 170 mg/dL, more preferably less than about 160 mg/dL, more preferably less than about 150 mg/dL, and most preferably less than about 140 mg/dL. Other examples of methods of treatment being assessed by a parameter included improving prothrombin times in a subject with hemophilia: e.g., administering a BPXTEN comprising a FIX can result in a prothrombin time that is at least about 40%, more preferably at least about 50%, more preferably at least about 60%, more preferably at least about 70%, more preferably at least about 80%, more preferably at least about 90%, or more preferably at least about 95% compared to a normal subject.
The invention further contemplates that BPXTEN used in accordance with the methods provided herein may be administered in conjunction with other treatment methods and pharmaceutical compositions useful for treating diabetes, insulin resistance, metabolic disorders, bleeding disorders, or growth disorders. Such compositions, may include for example, DPP-IV inhibitors, insulin, insulin analogues, PPAR gamma agonists, dual-acting PPAR agonists, GLP-1 agonists or analogues, PTP1B inhibitors, SGLT inhibitors, insulin secretagogues, RXR agonists, glycogen synthase kinase-3 inhibitors, insulin sensitizers, immune modulators, beta-3 adrenergic receptor agonists, Pan-PPAR agonists, 11beta-HSD1 inhibitors, biguanides, alpha-glucosidase inhibitors, meglitinides, thiazolidinediones, sulfonylureas and other diabetes medicants known in the art, or anti-hypertensive drugs, calcium channel blockers, or coagulation factors and related products. In some cases, the administration of a BPXTEN may permit use of lower dosages of the co-administered pharmaceutical composition to achieve a comparable clinical effect or measured parameter for the disease, disorder or condition in the subject.
The foregoing notwithstanding, in certain embodiments, the BPXTEN used in accordance with the methods of the present invention may prevent or delay the need for additional treatment methods or use of drugs or other pharmaceutical compositions in subjects with glucose-related diseases, metabolic diseases or disorders, coagulation disorders, or growth-hormone deficiency or growth disorders. In other embodiments, the BPXTEN may reduce the amount, frequency or duration of additional treatment methods or drugs or other pharmaceutical compositions required to treat the underlying disease, disorder or condition.
In another aspect, the invention provides a method of designing the BPXTEN compositions with desired pharmacologic or pharmaceutical properties. The BPXTEN fusion proteins are designed and prepared with various objectives in mind (compared to the BP components not linked to the fusion protein), including improving the therapeutic efficacy for the treatment of metabolic diseases or disorders, enhancing the pharmacokinetic characteristics of the fusion proteins compared to the BP, lowering the dose or frequency of dosing required to achieve a pharmacologic effect, enhancing the pharmaceutical properties, and to enhance the ability of the BP components to remain within the therapeutic window for an extended period of time.
In general, the steps in the design and production of the fusion proteins and the inventive compositions may, as illustrated in
In other cases, where in increase in half-life is not required, but an increase in a pharmaceutical property (e.g., solubility) is desired, a BPXTEN can be designed to include XTEN of shorter lengths. In some embodiments of the foregoing, the BPXTEN can comprise a BP linked to an XTEN having at least about 24, or about 36, or about 48, or about 60, or about 72, or about 84, or about 96 amino acid residues, in which the solubility of the fusion protein under physiologic conditions is at least three-fold greater than the corresponding BP not linked to XTEN, or alternatively, at least four-fold, or five-fold, or six-fold, or seven-fold, or eight-fold, or nine-fold, or at least 10-fold, or at least 20-fold, or at least 30-fold, or at least 50-fold, or at least 60-fold or greater than glucagon not linked to XTEN. In one embodiment of the foregoing, the BP is glucagon. In another embodiment of the foregoing, a BPXTEN can comprise glucagon and a polypeptide sequence selected from Tables 12-15. In still other cases, where a half-life of 2-6 hours for a glucagon-containing BPXTEN fusion protein is desired (e.g., in the treatment of nocturnal hypoglycemia), a fusion protein can be designed with XTEN of intermediate lengths such as about 100 amino acids, or about 144 amino acids, or about 156 amino acids, or about 168 amino acids, or about 180 amino acids, or about 196 amino acids in the XTEN component of the glucagon-containing BPXTEN.
In another aspect, the invention provides methods of making BPXTEN compositions to improve ease of manufacture, result in increased stability, increased water solubility, and/or ease of formulation, as compared to the native BPs. In one embodiment, the invention includes a method of increasing the water solubility of a BP comprising the step of linking the BP to one or more XTEN such that a higher concentration in soluble form of the resulting BPXTEN can be achieved, under physiologic conditions, compared to the BP in an un-fused state. Factors that contribute to the property of XTEN to confer increased water solubility of BPs when incorporated into a fusion protein include the high solubility of the XTEN fusion partner and the low degree of self-aggregation between molecules of XTEN in solution. In some embodiments, the method results in a BPXTEN fusion protein wherein the water solubility is at least about 50%, or at least about 60% greater, or at least about 70% greater, or at least about 80% greater, or at least about 90% greater, or at least about 100% greater, or at least about 150% greater, or at least about 200% greater, or at least about 400% greater, or at least about 600% greater, or at least about 800% greater, or at least about 1000% greater, or at least about 2000% greater, or at least about 4000% greater, or at least about 6000% greater under physiologic conditions, compared to the un-fused BP.
In another embodiment, the invention includes a method of enhancing the shelf-life of a BP comprising the step of linking the BP with one or more XTEN selected such that the shelf-life of the resulting BPXTEN is extended compared to the BP in an un-fused state. As used herein, shelf-life refers to the period of time over which the functional activity of a BP or BPXTEN that is in solution or in some other storage formulation remains stable without undue loss of activity. As used herein, “functional activity” refers to a pharmacologic effect or biological activity, such as the ability to bind a receptor or ligand, or an enzymatic activity, or to display one or more known functional activities associated with a BP, as known in the art. A BP that degrades or aggregates generally has reduced functional activity or reduced bioavailability compared to one that remains in solution. Factors that contribute to the ability of the method to extend the shelf life of BPs when incorporated into a fusion protein include the increased water solubility, reduced self-aggregation in solution, and increased heat stability of the XTEN fusion partner. In particular, the low tendency of XTEN to aggregate facilitates methods of formulating pharmaceutical preparations containing higher drug concentrations of BPs, and the heat-stability of XTEN contributes to the property of BPXTEN fusion proteins to remain soluble and functionally active for extended periods. In one embodiment, the method results in BPXTEN fusion proteins with “prolonged” or “extended” shelf-life that exhibit greater activity relative to a standard that has been subjected to the same storage and handling conditions. The standard may be the un-fused full-length BP. In one embodiment, the method includes the step of formulating the isolated BPXTEN with one or more pharmaceutically acceptable excipients that enhance the ability of the XTEN to retain its unstructured conformation and for the BPXTEN to remain soluble in the formulation for a time that is greater than that of the corresponding un-fused BP. In one embodiment, the method encompasses linking a BP to an XTEN to create a BPXTEN fusion protein results in a solution that retains greater than about 100% of the functional activity, or greater than about 105%, 110%, 120%, 130%, 150% or 200% of the functional activity of a standard when compared at a given time point and when subjected to the same storage and handling conditions as the standard, thereby enhancing its shelf-life.
Shelf-life may also be assessed in terms of functional activity remaining after storage, normalized to functional activity when storage began. BPXTEN fusion proteins of the invention with prolonged or extended shelf-life as exhibited by prolonged or extended functional activity may retain about 50% more functional activity, or about 60%, 70%, 80° %, or 90% more of the functional activity of the equivalent BP not linked to XTEN when subjected to the same conditions for the same period of time. For example, a BPXTEN fusion protein of the invention comprising exendin-4 or glucagon fused to a XTEN sequence may retain about 80% or more of its original activity in solution for periods of up to 5 weeks or more under various temperature conditions. In some embodiments, the BPXTEN retains at least about 50%, or about 60%, or at least about 70%, or at least about 80/%, and most preferably at least about 90% or more of its original activity in solution when heated at 80° C. for 10 min. In other embodiments, the BPXTEN retains at least about 50%, preferably at least about 60%, or at least about 70%, or at least about 80%, or alternatively at least about 90% or more of its original activity in solution when heated or maintained at 37° C. for about 7 days. In another embodiment, BPXTEN fusion protein retains at least about 80% or more of its functional activity after exposure to a temperature of about 30° C. to about 70° C. over a period of time of about one hour to about 18 hours. In the foregoing embodiments hereinabove described in this paragraph, the retained activity of the BPXTEN would be at least about two-fold, or at least about three-fold, or at least about four-fold, or at least about five-fold, or at least about six-fold greater at a given time point than that of the corresponding BP not linked to the fusion protein.
VI). The DNA Sequences of the Invention
The present invention provides isolated polynucleic acids encoding BPXTEN chimeric polypeptides and sequences complementary to polynucleic acid molecules encoding BPXTEN chimeric polypeptides, including homologous variants. In another aspect, the invention encompasses methods to produce polynucleic acids encoding BPXTEN chimeric polypeptides and sequences complementary to poly nucleic acid molecules encoding BPXTEN chimeric polypeptides, including homologous variants. In general, and as illustrated in
In accordance with the invention, nucleic acid sequences that encode BPXTEN may be used to generate recombinant DNA molecules that direct the expression of BPXTEN fusion proteins in appropriate host cells. Several cloning strategies are envisioned to be suitable for performing the present invention, many of which can be used to generate a construct that comprises a gene coding for a fusion protein of the BPXTEN composition of the present invention, or its complement. In one embodiment, the cloning strategy would be used to create a gene that encodes a monomeric BPXTEN that comprises at least a first BP and at least a first XTEN polypeptide, or its complement. In another embodiment, the cloning strategy would be used to create a gene that encodes a monomeric BPXTEN that comprises a first and a second molecule of the one BP and at least a first XTEN (or its complement) that would be used to transform a host cell for expression of the fusion protein used to formulate a BPXTEN composition. In the foregoing embodiments hereinabove described in this paragraph, the gene can further comprise nucleotides encoding spacer sequences that may also encode cleavage sequence(s).
In designing a desired XTEN sequences, it was discovered that the non-repetitive nature of the XTEN of the inventive compositions can be achieved despite use of a “building block” molecular approach in the creation of the XTEN-encoding sequences. This was achieved by the use of a library of polynucleotides encoding sequence motifs that are then multimerized to create the genes encoding the XTEN sequences (see
In one approach, a construct is first prepared containing the DNA sequence corresponding to BPXTEN fusion protein. DNA encoding the BP of the compositions may be obtained from a cDNA library prepared using standard methods from tissue or isolated cells believed to possess BP mRNA and to express it at a detectable level. If necessary, the coding sequence can be obtained using conventional primer extension procedures as described in Sambrook, et al., supra, to detect precursors and processing intermediates of mRNA that may not have been reverse-transcribed into cDNA. Accordingly, DNA can be conveniently obtained from a cDNA library prepared from such sources. The BP encoding gene(s) may also be obtained from a genomic library or created by standard synthetic procedures known in the art (e.g., automated nucleic acid synthesis) using DNA sequences obtained from publicly available databases, patents, or literature references. Such procedures are well known in the art and well described in the scientific and patent literature. For example, sequences can be obtained from Chemical Abstracts Services (CAS) Registry Numbers (published by the American Chemical Society) and/or GenBank Accession Numbers (e.g., Locus ID, NP_XXXXX, and XP_XXXXX) Model Protein identifiers available through the National Center for Biotechnology Information (NCBI) webpage, available on the world wide web at ncbi.nlm.nih.gov that correspond to entries in the CAS Registry or GenBank database that contain an amino acid sequence of the BAP or of a fragment or variant of the BAP. For such sequence identifiers provided herein, the summary pages associated with each of these CAS and GenBank and GenSeq Accession Numbers as well as the cited journal publications (e.g., PubMed ID number (PMID)) are each incorporated by reference in their entireties, particularly with respect to the amino acid sequences described therein. In one embodiment, the BP encoding gene encodes a protein from any one of Tables 3-8, or a fragment or variant thereof.
A gene or polynucleotide encoding the BP portion of the subject BPXTEN protein, in the case of an expressed fusion protein that will comprise a single BP can be then be cloned into a construct, which can be a plasmid or other vector under control of appropriate transcription and translation sequences for high level protein expression in a biological system. In a later step, a second gene or polynucleotide coding for the XTEN is genetically fused to the nucleotides encoding the N- and/or C-terminus of the BP gene by cloning it into the construct adjacent and in frame with the gene(s) coding for the BP. This second step can occur through a ligation or multimerization step. In the foregoing embodiments hereinabove described in this paragraph, it is to be understood that the gene constructs that are created can alternatively be the complement of the respective genes that encode the respective fusion proteins.
The gene encoding for the XTEN can be made in one or more steps, either fully synthetically or by synthesis combined with enzymatic processes, such as restriction enzyme-mediated cloning, PCR and overlap extension. XTEN polypeptides can be constructed such that the XTEN-encoding gene has low repetitiveness while the encoded amino acid sequence has a degree of repetitiveness. Genes encoding XTEN with non-repetitive sequences can be assembled from oligonucleotides using standard techniques of gene synthesis. The gene design can be performed using algorithms that optimize codon usage and amino acid composition. In one method of the invention, a library of relatively short XTEN-encoding polynucleotide constructs is created and then assembled, as illustrated in
Polynucleotide Libraries
In another aspect, the invention provides libraries of polynucleotides that encode XTEN sequences that can be used to assemble genes that encode XTEN of a desired length and sequence.
In certain embodiments, the XTEN-encoding library constructs comprise polynucleotides that encode polypeptide segments of a fixed length. As an initial step, a library of oligonucleotides that encode motifs of 9-14 amino acid residues can be assembled. In a preferred embodiment, libraries of oligonucleotides that encode motifs of 12 amino acids are assembled.
The XTEN-encoding sequence segments can be dimerized or multimerized into longer encoding sequences. Dimerization or multimerization can be performed by ligation, overlap extension, PCR assembly or similar cloning techniques known in the art. This process of can be repeated multiple times until the resulting XTEN-encoding sequences have reached the organization of sequence and desired length, providing the XTEN-encoding genes. As will be appreciated, a library of polynucleotides that encodes 12 amino acids can be dimerized into a library of polynucleotides that encode 36 amino acids. In turn, the library of polynucleotides that encode 36 amino acids can be serially dimerized into a library containing successively longer lengths of polynucleotides that encode XTEN sequences. In some embodiments, libraries can be assembled of polynucleotides that encode amino acids that are limited to specific sequence XTEN families, e.g., AD, AE, AF, AG, AM, or AQ sequences of Table 1. In other embodiments, libraries can comprises sequences that encode two or more of the motif family sequences from Table 1. The names and sequences of representative, non-limiting polynucleotide sequences of libraries that encode 36mers are presented in Tables 12-15, and the methods used to create them are described more fully in the Examples. The libraries can be used, in turn, for serial dimerization or ligation to achieve polynucleotide sequence libraries that encode XTEN sequences, for example, of 72, 144, 288, 576, 864, 912, 923, 1296 amino acids, or up to a total length of about 3000 amino acids, as well as intermediate lengths. In some cases, the polynuclcotide library sequences may also include additional bases used as “sequencing islands,” described more fully below.
One may clone the library of XTEN-encoding genes into one or more expression vectors known in the art. To facilitate the identification of well-expressing library members, one can construct the library as fusion to a reporter protein. Non-limiting examples of suitable reporter genes are green fluorescent protein, luciferace, alkaline phosphatase, and beta-galactosidase. By screening, one can identify short XTEN sequences that can be expressed in high concentration in the host organism of choice. Subsequently, one can generate a library of random XTEN dimers and repeat the screen for high level of expression. Subsequently, one can screen the resulting constructs for a number of properties such as level of expression, protease stability, or binding to antiserum.
One aspect of the invention is to provide polynucleotide sequences encoding the components of the fusion protein wherein the creation of the sequence has undergone codon optimization. Of particular interest is codon optimization with the goal of improving expression of the polypeptide compositions and to improve the genetic stability of the encoding gene in the production hosts. For example, codon optimization is of particular importance for XTEN sequences that are rich in glycine or that have very repetitive amino acid sequences. Codon optimization can be performed using computer programs (Gustafsson, C., et al. (2004) Trends Biotechnol, 22: 346-53), some of which minimize ribosomal pausing (Coda Genomics Inc.). In one embodiment, one can perform codon optimization by constructing codon libraries where all members of the library encode the same amino acid sequence but where codon usage is varied. Such libraries can be screened for highly expressing and genetically stable members that are particularly suitable for the large-scale production of XTEN-containing products. When designing XTEN sequences one can consider a number of properties. One can minimize the repetitiveness in the encoding DNA sequences. In addition, one can avoid or minimize the use of codons that are rarely used by the production host (e.g. the AGG and AGA arginine codons and one leucine codon in E. coli). In the case of E. coli, two glycine codons, GGA and GGG, are rarely used in highly expressed proteins. Thus codon optimization of the gene encoding XTEN sequences can be very desirable. DNA sequences that have a high level of glycine tend to have a high GC content that can lead to instability or low expression levels. Thus, when possible, it is preferred to choose codons such that the GC-content of XTEN-encoding sequence is suitable for the production organism that will be used to manufacture the XTEN.
Optionally, the full-length XTEN-encoding gene may comprise one or more sequencing islands. In this context, sequencing islands are short-stretch sequences that are distinct from the XTEN library construct sequences and that include a restriction site not present or expected to be present in the full-length XTEN-encoding gene. In one embodiment, a sequencing island is the sequence
In another embodiment, a sequencing island is the sequence
As an alternative, one can construct codon libraries where all members of the library encode the same amino acid sequence but where codon usage is varied. Such libraries can be screened for highly expressing and genetically stable members that are particularly suitable for the large-scale production of XTEN-containing products.
Optionally, one can sequence clones in the library to eliminate isolates that contain undesirable sequences. The initial library of short XTEN sequences can allow some variation in amino acid sequence. For instance one can randomize some codons such that a number of hydrophilic amino acids can occur in a particular position.
During the process of iterative multimerization one can screen the resulting library members for other characteristics like solubility or protease resistance in addition to a screen for high-level expression.
Once the gene that encodes the XTEN of desired length and properties is selected, it is genetically fused to the nucleotides encoding the N- and/or the C-terminus of the BP gene(s) by cloning it into the construct adjacent and in frame with the gene coding for BP or adjacent to a spacer sequence. The invention provides various permutations of the foregoing, depending on the BPXTEN to be encoded. For example, a gene encoding a BPXTEN fusion protein comprising two BP such as embodied by formula III or IV, as depicted above, the gene would have polynucleotides encoding two BP, at least a first XTEN, and optionally a second XTEN and/or spacer sequences. The step of cloning the BP genes into the XTEN construct can occur through a ligation or multimerization step. As shown in
The invention also encompasses polynucleotides comprising XTEN-encoding polynucleotide variants that have a high percentage of sequence identity to (a) a polynucleotide sequence from Table 11, or (b) sequences that are complementary to the polynucleotides of (a). A polynucleotide with a high percentage of sequence identity is one that has at least about an 80% nucleic acid sequence identity, alternatively at least about 81%, alternatively at least about 82%, alternatively at least about 83%, alternatively at least about 84%, alternatively at least about 85%, alternatively at least about 86%, alternatively at least about 87%, alternatively at least about 88%, alternatively at least about 89%, alternatively at least about 90%, alternatively at least about 91%, alternatively at least about 92%, alternatively at least about 93%, alternatively at least about 94%, alternatively at least about 95%, alternatively at least about 96%, alternatively at least about 97%, alternatively at least about 98%, and alternatively at least about 99% nucleic acid sequence identity to (a) or (b) of the foregoing, or that can hybridize with the target polynucleotide or its complement under stringent conditions.
Homology, sequence similarity or sequence identity of nucleotide or amino acid sequences may also be determined conventionally by using known software or computer programs such as the BestFit or Gap pairwise comparison programs (GCG Wisconsin Package, Genetics Computer Group, 575 Science Drive. Madison. Wis. 53711). BestFit uses the local homology algorithm of Smith and Waterman (Advances in Applied Mathematics. 1981. 2: 482-489), to find the best segment of identity or similarity between two sequences. Gap performs global alignments: all of one sequence with all of another similar sequence using the method of Needleman and Wunsch, (Journal of Molecular Biology. 1970. 48:443-453). When using a sequence alignment program such as BestFit, to determine the degree of sequence homology, similarity or identity, the default setting may be used, or an appropriate scoring matrix may be selected to optimize identity, similarity or homology scores.
Nucleic acid sequences that are “complementary” are those that are capable of base-pairing according to the standard Watson-Crick complementarity rules. As used herein, the term “complementary sequences” means nucleic acid sequences that are substantially complementary, as may be assessed by the same nucleotide comparison set forth above, or as defined as being capable of hybridizing to the polynucleotides that encode the BPXTEN sequences under stringent conditions, such as those described herein.
The resulting polynucleotides encoding the BPXTEN chimeric compositions can then be individually cloned into an expression vector. The nucleic acid sequence may be inserted into the vector by a variety of procedures. In general, DNA is inserted into an appropriate restriction endonuclease site(s) using techniques known in the art. Vector components generally include, but are not limited to, one or more of a signal sequence, an origin of replication, one or more marker genes, an enhancer element, a promoter, and a transcription termination sequence. Construction of suitable vectors containing one or more of these components employs standard ligation techniques which are known to the skilled artisan. Such techniques are well known in the art and well described in the scientific and patent literature.
Various vectors are publicly available. The vector may, for example, be in the form of a plasmid, cosmid, viral particle, or phage. Both expression and cloning vectors contain a nucleic acid sequence that enables the vector to replicate in one or more selected host cells. Such vector sequences are well known for a variety of bacteria, yeast, and viruses. Useful expression vectors that can be used include, for example, segments of chromosomal, non-chromosomal and synthetic DNA sequences. Suitable vectors include, but are not limited to, derivatives of SV40 and pcDNA and known bacterial plasmids such as col EI, pCR1, pBR322, pMa1-C2, pET, pGEX as described by Smith, et al., Gene 57:31-40 (1988), pMB9 and derivatives thereof, plasmids such as RP4, phage DNAs such as the numerous derivatives of phage I such as NM98 9, as well as other phage DNA such as M 13 and filamentous single stranded phage DNA; yeast plasmids such as the 2 micron plasmid or derivatives of the 2 m plasmid, as well as centromeric and integrative yeast shuttle vectors, vectors useful in eukaryotic cells such as vectors useful in insect or mammalian cells; vectors derived from combinations of plasmids and phage DNAs, such as plasmids that have been modified to employ phage DNA or the expression control sequences; and the like. The requirements are that the vectors are replicable and viable in the host cell of choice. Low- or high-copy number vectors may be used as desired.
Promoters suitable for use in expression vectors with prokaryotic hosts include the β-lactamase and lactose promoter systems [Chang et al., Nature, 275:615 (1978); Goeddel t al., Nature, 281:544 (1979)], alkaline phosphatase, a tryptophan (trp) promoter system [Goeddel, Nucleic Acids Res., 8:4057 (1980); EP 36,776], and hybrid promoters such as the tac promoter [deBoer et al., Proc. Natl. Acad. Sci. USA. 80:21-25 (1983)]. Promoters for use in bacterial systems can also contain a Shine-Dalgarno (S.D.) sequence operably linked to the DNA encoding BPXTEN polypeptides.
For example, in a baculovirus expression system, both non-fusion transfer vectors, such as, but not limited to pVL941 (BamHI cloning site, available from Summers, et al., Virology 84:390-402 (1978)), pVL1393 (BamHI, Smal, Xbal, EcoRI, IVotl, Xmalll, BgIII and Pstl cloning sites; Invitrogen), pVL1392 (BgIII, Pstl, NotI, XmaIII, EcoRI, Xball, Smal and BamHI cloning site; Summers, t al., Virology 84:390-402 (1978) and Invitrogen) and pBlucBacIII (BamHI, BgIII, Pstl, NcoI and Hindi II cloning site, with blue/white recombinant screening, Invitrogen), and fusion transfer vectors such as, but not limited to, pAc700 (BamHI and Kpnl cloning sites, in which the BamHI recognition site begins with the initiation codon; Summers, et al., Virology 84:390-402 (1978)), pAc701 and pAc70-2 (same as pAc700, with different reading frames), pAc360 [BamHI cloning site 36 base pairs downstream of a polyhedrin initiation codon; Invitrogen (1995)) and pBlueBacHisA, B, C (three different reading frames with BamH I, BgI II, Pstl, Nco 1 and Hind III cloning site, an N-terminal peptide for ProBond purification and blue/white recombinant screening of plaques; Invitrogen (220) can be used.
Mammalian expression vectors can comprise an origin of replication, a suitable promoter and enhancer, and also any necessary ribosome binding sites, polyadenylation site, splice donor and acceptor sites, transcriptional termination sequences, and 5′ flanking nontranscribed sequences. DNA sequences derived from the SV40 splice, and polyadenylation sites may be used to provide the required nontranscribed genetic elements. Mammalian expression vectors contemplated for use in the invention include vectors with inducible promoters, such as the dihydrofolate reductase promoters, any expression vector with a DHFR expression cassette or a DHFR/methotrexate co-amplification vector such as pED (Pstl, Sail, Sbal, Smal and EcoRI cloning sites, with the vector expressing both the cloned gene and DHFR; Randal J. Kaufman, 1991, Randal J. Kaufman, Current Protocols in Molecular Biology, 16, 12 (1991)). Alternatively a glutamine synthetase/methionine sulfoximine co-amplification vector, such as pEE14 (Hindlll, Xball, Smal, Sbal, EcoRI and Sell cloning sites in which the vector expresses glutamine synthetase and the cloned gene; Celltech). A vector that directs episomal expression under the control of the Epstein Barr Virus (EBV) or nuclear antigen (EBNA) can be used such as pREP4 (BamHI r SfH, Xhol, NotI, Nhel, Hindi II, NheI, Pvull and Kpnl cloning sites, constitutive RSV-LTR promoter, hygromycin selectable marker; Invitrogen), pCEP4 (BamHI, SfH, Xhol, NotI, Nhel, Hindlll, Nhel, PvuII and Kpnl cloning sites, constitutive hCMV immediate early gene promoter, hygromycin selectable marker; Invitrogen), pMEP4 (.Kpnl, Pvul, Nhel, Hindlll, NotI, Xhol, Sfil, BamHI cloning sites, inducible metallothionein H a gene promoter, hygromycin selectable marker, Invitrogen), pREP8 (BamHI, Xhol, NotI, Hindlll, Nhel and Kpnl cloning sites, RSV-LTR promoter, histidinol selectable marker: Invitrogen), pREP9 (Kpnl, Nhel, Hind lll, NotI, Xho 1, Sfi 1, BamH I cloning sites, RSV-LTR promoter, G418 selectable marker; Invitrogen), and pEBVHis (RSV-LTR promoter, hygromycin selectable marker, N-terminal peptide purifiable via ProBond resin and cleaved by enterokinase: Invitrogen).
Selectable mammalian expression vectors for use in the invention include, but are not limited to, pRc/CMV (Hind lll, BstXI, NotI, Sbal and Apal cloning sites, G418 selection, Invitrogen), pRc/RSV (Hind II, Spel, BstXI, NotI, Xbal cloning sites. G418 selection, Invitrogen) and the like. Vaccinia virus mammalian expression vectors (see, for example, Randall J. Kaufman, Current Protocols in Molecular Biology 16.12 (Frederick M. Ausubel, et al., eds. Wiley 1991) that can be used in the present invention include, but are not limited to, pSC11 (Smal cloning site. TK- and beta-gal selection), pMJ601 (Sal 1. Sma 1, A flI, Narl. BspMlI, BamHI, Apal, Nhel, SacII, Kpnl and Hindlll cloning sites: TK- and -gal selection), pTKgptFlS (EcoRI, Pstl, SaIII, Accl, HindII, Sbal, BamHI and Hpa cloning sites, TK or XPRT selection) and the like.
Yeast expression systems that can also be used in the present invention include, but are not limited to, the non-fusion pYES2 vector (XJbal, Sphl, Shol, NotI, GstXI, EcoRI, BstXI, BamHI, Sad, Kpnl and Hindlll cloning sites, Invitrogen), the fusion pYESHisA, B, C (Xball, Sphl, Shol, NotI, BstXI, EcoRI, BamHI, Sad, Kpnl and Hindi II cloning sites, N-terminal peptide purified with ProBond resin and cleaved with enterokinase; Invitrogen), pRS vectors and the like.
In addition, the expression vector containing the chimeric BPXTEN fusion protein-encoding polynucleotide molecule may include drug selection markers. Such markers aid in cloning and in the selection or identification of vectors containing chimeric DNA molecules. For example, genes that confer resistance to neomycin, puromycin, hygromycin, dihydrofolate reductase (DHFR) inhibitor, guanine phosphoribosyl transferase (GPT), zeocin, and histidinol are useful selectable markers. Alternatively, enzymes such as herpes simplex virus thymidine kinase (tk) or chloramphenicol acetyltransferase (CAT) may be employed. Immunologic markers also can be employed. Any known selectable marker may be employed so long as it is capable of being expressed simultaneously with the nucleic acid encoding a gene product. Further examples of selectable markers are well known to one of skill in the art and include reporters such as enhanced green fluorescent protein (EGFP), beta-galactosidase (β-gal) or chloramphenicol acetyltransferase (CAT).
In one embodiment, the polynucleotide encoding a BPXTEN fusion protein composition can be fused C-terminally to an N-terminal signal sequence appropriate for the expression host system. Signal sequences are typically proteolytically removed from the protein during the translocation and secretion process, generating a defined N-terminus. A wide variety of signal sequences have been described for most expression systems, including bacterial, yeast, insect, and mammalian systems. A non-limiting list of preferred examples for each expression system follows herein. Preferred signal sequences are OmpA, PhoA, and DsbA for E. coli expression. Signal peptides preferred for yeast expression are ppL-alpha, DEX4, invertase signal peptide, acid phosphatase signal peptide, CPY, or INU1. For insect cell expression the preferred signal sequences are sexta adipokinetic hormone precursor, CP1, CP2, CP3, CP4, TPA, PAP, or gp67. For mammalian expression the preferred signal sequences are IL2L, SV40, IgG kappa and IgG lambda.
In another embodiment, a leader sequence, potentially comprising a well-expressed, independent protein domain, can be fused to the N-terminus of the BPXTEN sequence, separated by a protease cleavage site. While any leader peptide sequence which does not inhibit cleavage at the designed proteolytic site can be used, sequences in preferred embodiments will comprise stable, well-expressed sequences such that expression and folding of the overall composition is not significantly adversely affected, and preferably expression, solubility, and/or folding efficiency are significantly improved. A wide variety of suitable leader sequences have been described in the literature. A non-limiting list of suitable sequences includes maltose binding protein, cellulose binding domain, glutathione S-transferase, 6×His tag (SEQ ID NO: 263), FLAG tag, hemaglutinin tag, and green fluorescent protein. The leader sequence can also be further improved by codon optimization, especially in the second codon position following the ATG start codon, by methods well described in the literature and hereinabove.
Various in vitro enzymatic methods for cleaving proteins at specific sites are known. Such methods include use of enterokinase (DDDK (SEQ ID NO: 264)), Factor Xa (IDGR (SEQ ID NO: 265)), thrombin (LVPRGS (SEQ ID NO: 266)), PreScission™ (LEVLFQGP (SEQ ID NO: 267)), TEV protease (EQLYFQG (SEQ ID NO: 268)), 3C protease (ETLFQGP (SEQ ID NO: 269)), Sortase A (LPETG), Granzyme B (D/X, N/X, M/N or S/X), inteins, SUMO, DAPase (TAGZyme™), Aeromonas aminopeptidase. Aminopeptidase M, and carboxypeptidases A and B. Additional methods are disclosed in Amau, et al., Protein Expression and Purification 48: 1-13 (2006).
In other embodiments, an optimized polynucleotide sequence encoding at least about 20 to about 60 amino acids with XTEN characteristics can be included at the N-terminus of the XTEN sequence to promote the initiation of translation to allow for expression of XTEN fusions at the N-terminus of proteins without the presence of a helper domain. In an advantage of the foregoing, the sequence does not require subsequent cleavage, thereby reducing the number of steps to manufacture XTEN-containing compositions. As described in more detail in the Examples, the optimized N-terminal sequence has attributes of an unstructured protein, but may include nucleotide bases encoding amino acids selected for their ability to promote initiation of translation and enhanced expression. In one embodiment of the foregoing, the optimized polynucleotide encodes an XTEN sequence with at least about 90% sequence identity to AE912 (SEQ ID NO: 217). In another embodiment of the foregoing, the optimized polynucleotide encodes an XTEN sequence with at least about 90% sequence identity to AM923 (SEQ ID NO: 218).
In another embodiment, the protease site of the leader sequence construct is chosen such that it is recognized by an in vivo protease. In this embodiment, the protein is purified from the expression system while retaining the leader by avoiding contact with an appropriate protease. The full-length construct is then injected into a patient. Upon injection, the construct comes into contact with the protease specific for the cleavage site and is cleaved by the protease. In the case where the uncleaved protein is substantially less active than the cleaved form, this method has the beneficial effect of allowing higher initial doses while avoiding toxicity, as the active form is generated slowly in vivo. Some non-limiting examples of in vivo proteases which are useful for this application include tissue kallikrein, plasma kallikrein, trypsin, pepsin, chymotrypsin, thrombin, and matrix metalloproteinases, or the proteases of Table 10.
In this manner, a chimeric DNA molecule coding for a monomeric BPXTEN fusion protein is generated within the construct. Optionally, this chimeric DNA molecule may be transferred or cloned into another construct that is a more appropriate expression vector. At this point, a host cell capable of expressing the chimeric DNA molecule can be transformed with the chimeric DNA molecule. The vectors containing the DNA segments of interest can be transferred into the host cell by well-known methods, depending on the type of cellular host. For example, calcium chloride transfection is commonly utilized for prokaryotic cells, whereas calcium phosphate treatment, lipofection, or electroporation may be used for other cellular hosts. Other methods used to transform mammalian cells include the use of polybrene, protoplast fusion, liposomes, electroporation, and microinjection. See, generally, Sambrook, et al., supra.
The transformation may occur with or without the utilization of a carrier, such as an expression vector. Then, the transformed host cell is cultured under conditions suitable for expression of the chimeric DNA molecule encoding of BPXTEN.
The present invention also provides a host cell for expressing the monomeric fusion protein compositions disclosed herein. Examples of suitable eukaryotic host cells include, but are not limited to mammalian cells, such as VERO cells, HELA cells such as ATCC No. CCL2, CHO cell lines, COS cells, WI38 cells, BHK cells, HepG2 cells, 3T3 cells, A549 cells, PC12 cells, K562 cells, 293 cells, Sf9 cells and CvI cells. Examples of suitable non-mammalian eukaryotic cells include eukaryotic microbes such as filamentous fungi or yeast are suitable cloning or expression hosts for encoding vectors. Saccharomyces cerevisiae is a commonly used lower eukaryotic host microorganism. Others include Schizosaccharomyces pombe (Beach and Nurse, Nature, 290: 140 [1981]; EP 139,383 published 2 May 1985); Kluyveromyces hosts (U.S. Pat. No. 4,943,529: Fleer et al., Bio/Technology, 9:968-975 (1991)) such as, e.g., K. lactis (MW98-8C, CBS683, CBS4574; Louvencourt et al., J. Bacteriol., 737 [1983]), K. fragilis (ATCC 12,424), K. bulgaricus (ATCC 16,045), K. wickeramii (ATCC 24,178), K. waltii (ATCC 56,500), K. drosophilarum (ATCC 36,906; Van den Berg et al., Bio/Technology, 8:135 (1990)), K. thermotolerans, and K. marxianus; yarrowia (EP 402,226); Pichia pastoris (EP 183,070; Sreekrishna et al., J. Basic Microbiol., 28:265-278 [1988]); Candida; Trichoderma reesia (EP 244,234); Neurospora crassa (Case et al., Proc. Natl. Acad. Sci. USA, 76:5259-5263 [1979]); Schwanniomyces such as Schwanniomyces occidentalis (EP 394,538 published 31 Oct. 1990); and filamentous fungi such as, e.g., Neurospora. Penicillium, Tolypocladium (WO 91/00357 published 10 Jan. 1991), and Aspergillus hosts such as A. nidulans (Ballance et al., Biochem. Biophys. Res. Commun., 112:284-289 [1983]; Tilburn et al., Gene, 26:205-221 119831; Yelton et al., Proc. Natl. Acad. Sci. USA, 81: 1470-1474 [1984]) and A. niger (Kelly and Hynes, EMBO J., 4:475-479 [1985]). Methylotropic yeasts are suitable herein and include, but are not limited to, yeast capable of growth on methanol selected from the genera consisting of Hansenula, Candida, Kloeckera, Pichia, Saccharomvices, Torulopsis, and Rhodotorula. A list of specific species that are exemplary of this class of yeasts may be found in C. Anthony, The Biochemistry of Methylotrophs, 269 (1982).
Other suitable cells that can be used in the present invention include, but are not limited to, prokaryotic host cells strains such as Escherichia coli. (e.g., strain DH5-α). Bacillus subtilis, Salmonella typhimurium, or strains of the genera of Pseudomonas. Streptomyces and Staphylococcus. Non-limiting examples of suitable prokaryotes include those from the genera: Actinoplanes: Archaeoglobus: Bdellovibrno: Borrelia; Chloroflexus; Enterococcus; Escherichia; Lactobacilhus; Listeria; Oceanobacillus: Paracoccus; Pseudomonas: Staphylococcus: Streptococcus; Streptomyces; Thermoplasnma; and Vibrio. Non-limiting examples of specific strains include: Archaeoglobus fulgidus; Bdellovibrio bacteriovorus: Borrelia burgdorerin: Chloroflexus aurantiacus: Enterococcus faecalis; Enterococcus faecium; Lactobacillus johnsonii: Lactobacillus plantarum: Lactococcus lactis: Listeria innocua: Listeria monocytogenes; Oceanobacillus iheyensis: Paracoccus zeaxanthinifaciens: Pseudomonas mevalonii: Staphylococcus aureus; Staphylococcus epidermidis; Staphylococcus haemolyticus; Streptococcus agalactiae; Streptomyces griseolosporeus; Streptococcus mutans: Streptococcus pneumoniae; Streptococcus pyogenes; Thermoplasma acidophilum: Thermoplasma volcanium: Vibrio cholerae; Vibrio parahaemolyticus; and Vibrio vulnificus.
Host cells containing the polynucleotides of interest can be cultured in conventional nutrient media (e.g., Ham's nutrient mixture) modified as appropriate for activating promoters, selecting transformants or amplifying genes. The culture conditions, such as temperature, pH and the like, are those previously used with the host cell selected for expression, and will be apparent to the ordinarily skilled artisan. Cells are typically harvested by centrifugation, disrupted by physical or chemical means, and the resulting crude extract retained for further purification. For compositions secreted by the host cells, supernatant from centrifugation is separated and retained for further purification. Microbial cells employed in expression of proteins can be disrupted by any convenient method, including freeze-thaw cycling, sonication, mechanical disruption, or use of cell lysing agents, all of which are well known to those skilled in the art. Embodiments that involve cell lysis may entail use of a buffer that contains protease inhibitors that limit degradation after expression of the chimeric DNA molecule. Suitable protease inhibitors include, but are not limited to leupeptin, pepstatin or aprotinin. The supernatant then may be precipitated in successively increasing concentrations of saturated ammonium sulfate.
Gene expression may be measured in a sample directly, for example, by conventional Southern blotting, Northern blotting to quantitate the transcription of mRNA ([Thomas, Proc. Natl. Acad. Sci. USA, 77:5201-5205 (1980)]), dot blotting (DNA analysis), or in situ hybridization, using an appropriately labeled probe, based on the sequences provided herein. Alternatively, antibodies may be employed that can recognize specific duplexes, including DNA duplexes, RNA duplexes, and DNA-RNA hybrid duplexes or DNA-protein duplexes. The antibodies in turn may be labeled and the assay may be carried out where the duplex is bound to a surface, so that upon the formation of duplex on the surface, the presence of antibody bound to the duplex can be detected.
Gene expression, alternatively, may be measured by immunological of fluorescent methods, such as immunohistochemical staining of cells or tissue sections and assay of cell culture or body fluids or the detection of selectable markers, to quantitate directly the expression of gene product. Antibodies useful for immunohistochemical staining and/or assay of sample fluids may be either monoclonal or polyclonal, and may be prepared in any mammal. Conveniently, the antibodies may be prepared against a native sequence BP polypeptide or against a synthetic peptide based on the DNA sequences provided herein or against exogenous sequence fused to BP and encoding a specific antibody epitope. Examples of selectable markers are well known to one of skill in the art and include reporters such as enhanced green fluorescent protein (EGFP), beta-galactosidase (β-gal) or chloramphenicol acetyltransferase (CAT).
Expressed BPXTEN polypeptide product(s) may be purified via methods known in the art or by methods disclosed herein. Procedures such as gel filtration, affinity purification, salt fractionation, ion exchange chromatography, size exclusion chromatography, hydroxyapatite adsorption chromatography, hydrophobic interaction chromatography and gel electrophoresis may be used, each tailored to recover and purify the fusion protein produced by the respective host cells. Some expressed BPXTEN may require refolding during isolation and purification. Methods of purification are described in Robert K. Scopes. Protein Purification: Principles and Practice. Charles R. Castor (ed.), Springer-Verlag 1994, and Sambrook, et al., supra. Multi-step purification separations are also described in Baron, et al., Crit. Rev. Biotechnol. 10:179-90 (1990) and Below, et al., J. Chromatogr. A. 679:67-83 (1994).
VII). Pharmaceutical Compositions
The present invention provides pharmaceutical compositions comprising BPXTEN. In one embodiment, the pharmaceutical composition comprises the BPXTEN fusion protein and at least one pharmaceutically acceptable carrier. BPXTEN polypeptides of the present invention can be formulated according to known methods to prepare pharmaceutically useful compositions, whereby the polypeptide is combined in admixture with a pharmaceutically acceptable carrier vehicle, such as aqueous solutions or buffers, pharmaceutically acceptable suspensions and emulsions. Examples of non-aqueous solvents include propyl ethylene glycol, polyethylene glycol and vegetable oils. Therapeutic formulations are prepared for storage by mixing the active ingredient having the desired degree of purity with optional physiologically acceptable carriers, excipients or stabilizers, as described in Remington's Pharmaceutical Sciences 16th edition, Osol, A. Ed. (1980), in the form of lyophilized formulations or aqueous solutions.
The pharmaceutical compositions can be administered orally, intranasally, parenterally or by inhalation therapy, and may take the form of tablets, lozenges, granules, capsules, pills, ampoules, suppositories or aerosol form. They may also take the form of suspensions, solutions and emulsions of the active ingredient in aqueous or nonaqueous diluents, syrups, granulates or powders. In addition, the pharmaceutical compositions can also contain other pharmaceutically active compounds or a plurality of compounds of the invention.
More particularly, the present pharmaceutical compositions may be administered for therapy by any suitable route including oral, rectal, nasal, topical (including transdermal, aerosol, buccal and sublingual), vaginal, parenteral (including subcutaneous, subcutaneous by infusion pump, intramuscular, intravenous and intradermal), intravitreal, and pulmonary. It will also be appreciated that the preferred route will vary with the condition and age of the recipient, and the disease being treated.
In one embodiment, the pharmaceutical composition is administered subcutaneously. In this embodiment, the composition may be supplied as a lyophilized powder to be reconstituted prior to administration. The composition may also be supplied in a liquid form, which can be administered directly to a patient. In one embodiment, the composition is supplied as a liquid in a pre-filled syringe such that a patient can easily self-administer the composition.
Extended release formulations useful in the present invention may be oral formulations comprising a matrix and a coating composition. Suitable matrix materials may include waxes (e.g., camauba, bees wax, paraffin wax, ceresine, shellac wax, fatty acids, and fatty alcohols), oils, hardened oils or fats (e.g., hardened rapeseed oil, castor oil, beef tallow, palm oil, and soya bean oil), and polymers (e.g., hydroxypropyl cellulose, polyvinylpyrrolidone, hydroxypropyl methyl cellulose, and polyethylene glycol). Other suitable matrix tabletting materials are microcrystalline cellulose, powdered cellulose, hydroxypropyl cellulose, ethyl cellulose, with other carriers, and fillers. Tablets may also contain granulates, coated powders, or pellets. Tablets may also be multi-layered. Multi-layered tablets are especially preferred when the active ingredients have markedly different pharmacokinetic profiles. Optionally, the finished tablet may be coated or uncoated.
The coating composition may comprise an insoluble matrix polymer and/or a water soluble material. Water soluble materials can be polymers such as polyethylene glycol, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyvinylpyrrolidone, polyvinyl alcohol, or monomeric materials such as sugars (e.g., lactose, sucrose, fructose, mannitol and the like), salts (e.g., sodium chloride, potassium chloride and the like), organic acids (e.g., fumaric acid, succinic acid, lactic acid, and tartaric acid), and mixtures thereof. Optionally, an enteric polymer may be incorporated into the coating composition. Suitable enteric polymers include hydroxypropyl methyl cellulose, acetate succinate, hydroxypropyl methyl cellulose, phthalate, polyvinyl acetate phthalate, cellulose acetate phthalate, cellulose acetate trimellitate, shellac, zein, and polymethacrylates containing carboxyl groups. The coating composition may be plasticised by adding suitable plasticisers such as, for example, diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides, acetylated citrate esters, dibutylsebacate, and castor oil. The coating composition may also include a filler, which can be an insoluble material such as silicon dioxide, titanium dioxide, talc, kaolin, alumina, starch, powdered cellulose, MCC, or polacrilin potassium. The coating composition may be applied as a solution or latex in organic solvents or aqueous solvents or mixtures thereof. Solvents such as water, lower alcohol, lower chlorinated hydrocarbons, ketones, or mixtures thereof may be used.
The compositions of the invention may be formulated using a variety of excipients. Suitable excipients include microcrystalline cellulose (e.g. Avicel PH102, Avicel PH101), polymethacrylate, poly(ethyl acrylate, methyl methacrylate, trimethylammonioethyl methacrylate chloride) (such as Eudragit RS-30D), hydroxypropyl methylcellulose (Methocel K100M, Premium CR Methocel K100M, Methocel E5, Opadryn®), magnesium stearate, talc, triethyl citrate, aqueous ethylcellulose dispersion (Surelease®), and protamine sulfate. The slow release agent may also comprise a carrier, which can comprise, for example, solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents. Pharmaceutically acceptable salts can also be used in these slow release agents, for example, mineral salts such as hydrochlorides, hydrobromides, phosphates, or sulfates, as well as the salts of organic acids such as acetates, proprionates, malonates, or benzoates. The composition may also contain liquids, such as water, saline, glycerol, and ethanol, as well as substances such as wetting agents, emulsifying agents, or pH buffering agents. Liposomes may also be used as a carrier.
In another embodiment, the compositions of the present invention are encapsulated in liposomes, which have demonstrated utility in delivering beneficial active agents in a controlled manner over prolonged periods of time. Liposomes are closed bilayer membranes containing an entrapped aqueous volume. Liposomes may also be unilamellar vesicles possessing a single membrane bilayer or multilamellar vesicles with multiple membrane bilayers, each separated from the next by an aqueous layer. The structure of the resulting membrane bilayer is such that the hydrophobic (non-polar) tails of the lipid are oriented toward the center of the bilayer while the hydrophilic (polar) heads orient towards the aqueous phase. In one embodiment, the liposome may be coated with a flexible water soluble polymer that avoids uptake by the organs of the mononuclear phagocyte system, primarily the liver and spleen. Suitable hydrophilic polymers for surrounding the liposomes include, without limitation, PEG, polyvinylpyrrolidone, polyvinylmethylether, polymethyloxazoline, polyethyloxazoline, polyhydroxypropyloxazoline, polyhydroxypropylmethacrylamide, polymethacrylamide, polydimethylacrylamide, polyhydroxypropylmethacrylate, polyhydroxyethylacrylate, hydroxymethylcellulose hydroxyethylcellulose, polyethyleneglycol, polyaspartamide and hydrophilic peptide sequences as described in U.S. Pat. Nos. 6,316,024; 6,126,966; 6,056,973; 6,043,094, the contents of which are incorporated by reference in their entirety.
Liposomes may be comprised of any lipid or lipid combination known in the art. For example, the vesicle-forming lipids may be naturally-occurring or synthetic lipids, including phospholipids, such as phosphatidylcholine, phosphatidylethanolamine, phosphatidic acid, phosphatidylserine, phosphatidylglycerol, phosphatidylinositol, and sphingomyelin as disclosed in U.S. Pat. Nos. 6,056,973 and 5,874,104. The vesicle-forming lipids may also be glycolipids, cerebrosides, or cationic lipids, such as 1,2-dioleyloxy-3-(trimethylamino) propane (DOTAP); N-[1-(2,3,-ditetradecyloxy)propyl]-N,N-dimethyl-N-hydroxyethylammonium bromide (DMRIE); N-[1[(2,3,-dioleyloxy)propyl]-N,N-dimethyl-N-hydroxy ethylammonium bromide (DORIE): N-[1-(2,3-dioleyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA); 3 [N—(N′,N′-dimethylaminoethane) carbamoyl] cholesterol (DC-Chol); or dimethyldioctadecylammonium (DDAB) also as disclosed in U.S. Pat. No. 6,056,973. Cholesterol may also be present in the proper range to impart stability to the vesicle as disclosed in U.S. Pat. Nos. 5,916,588 and 5,874,104.
Additional liposomal technologies are described in U.S. Pat. Nos. 6,759,057; 6,406,713; 6,352,716; 6,316,024; 6,294,191; 6,126,966; 6,056,973; 6,043,094; 5,965,156; 5,916,588; 5,874,104; 5,215,680, and 4,684,479, the contents of which are incorporated herein by reference. These describe liposomes and lipid-coated microbubbles, and methods for their manufacture. Thus, one skilled in the art, considering both the disclosure of this invention and the disclosures of these other patents could produce a liposome for the extended release of the polypeptides of the present invention.
For liquid formulations, a desired property is that the formulation be supplied in a form that can pass through a 25, 28, 30, 31, 32 gauge needle for intravenous, intramuscular, intraarticular, or subcutaneous administration.
Administration via transdermal formulations can be performed using methods also known in the art, including those described generally in, e.g., U.S. Pat. Nos. 5,186,938 and 6,183,770, 4,861,800, 6,743,211, 6,945,952, 4,284,444, and WO 89/09051, incorporated herein by reference in their entireties. A transdermal patch is a particularly useful embodiment with polypeptides having absorption problems. Patches can be made to control the release of skin-permeable active ingredients over a 12 hour, 24 hour, 3 day, and 7 day period. In one example, a 2-fold daily excess of a polypeptide of the present invention is placed in a non-volatile fluid. The compositions of the invention are provided in the form of a viscous, non-volatile liquid. The penetration through skin of specific formulations may be measures by standard methods in the art (for example, Franz et al., J. Invest. Derm. 64:194-195 (1975)). Examples of suitable patches are passive transfer skin patches, iontophoretic skin patches, or patches with microneedles such as Nicoderm.
In other embodiments, the composition may be delivered via intranasal, buccal, or sublingual routes to the brain to enable transfer of the active agents through the olfactory passages into the CNS and reducing the systemic administration. Devices commonly used for this route of administration are included in U.S. Pat. No. 6,715,485. Compositions delivered via this route may enable increased CNS dosing or reduced total body burden reducing systemic toxicity risks associated with certain drugs. Preparation of a pharmaceutical composition for delivery in a subdermally implantable device can be performed using methods known in the art, such as those described in, e.g., U.S. Pat. Nos. 3,992,518; 5,660,848; and 5,756,115.
Osmotic pumps may be used as slow release agents in the form of tablets, pills, capsules or implantable devices. Osmotic pumps are well known in the art and readily available to one of ordinary skill in the art from companies experienced in providing osmotic pumps for extended release drug delivery. Examples are ALZA's DUROS™; ALZA's OROS™: Osmotica Pharmaceutical's Osmodex™ system; Shire Laboratories' EnSoTrol™ system; and Alzet™. Patents that describe osmotic pump technology are U.S. Pat. Nos. 6,890,918; 6,838,093; 6,814,979; 6,713,086; 6,534,090; 6,514,532; 6,361,796; 6,352,721; 6,294,201; 6,284,276; 6,110,498; 5,573,776; 4,200,0984; and 4,088,864, the contents of which are incorporated herein by reference. One skilled in the art, considering both the disclosure of this invention and the disclosures of these other patents could produce an osmotic pump for the extended release of the polypeptides of the present invention.
Syringe pumps may also be used as slow release agents. Such devices are described in U.S. Pat. Nos. 4,976,696; 4,933,185; 5,017,378; 6,309,370; 6,254,573; 4,435,173; 4,398,908; 6,572,585; 5,298,022; 5,176,502; 5,492,534; 5,318,540; and 4,988,337, the contents of which are incorporated herein by reference. One skilled in the art, considering both the disclosure of this invention and the disclosures of these other patents could produce a syringe pump for the extended release of the compositions of the present invention.
VIII). Pharmaceutical Kits
In another aspect, the invention provides a kit to facilitate the use of the BPXTEN polypeptides. In one embodiment, the kit comprises, in at least a first container: (a) an amount of a BPXTEN fusion protein composition sufficient to treat a disease, condition or disorder upon administration to a subject in need thereof; and (b) an amount of a pharmaceutically acceptable carrier; together in a formulation ready for injection or for reconstitution with sterile water, buffer, or dextrose; together with a label identifying the BPXTEN drug and storage and handling conditions, and a sheet of the approved indications for the drug, instructions for the reconstitution and/or administration of the BPXTEN drug for the use for the prevention and/or treatment of a approved indication, appropriate dosage and safety information, and information identifying the lot and expiration of the drug. In another embodiment of the foregoing, the kit can comprise a second container that can carry a suitable diluent for the BPXTEN composition, which will provide the user with the appropriate concentration of BPXTEN to be delivered to the subject.
The following example describes the construction of a collection of codon-optimized genes encoding motif sequences of 36 amino acids. As a first step, a stuffer vector pCW0359 was constructed based on a pET vector and that includes a T7 promoter. pCW0359 encodes a cellulose binding domain (CBD) and a TEV protease recognition site followed by a stuffer sequence that is flanked by BsaI, BbsI, and KpnI sites. The BsaI and BbsI sites were inserted such that they generate compatible overhangs after digestion. The stuffer sequence is followed by a truncated version of the GFP gene and a His tag. The stuffer sequence contains stop codons and thus E. coli cells carrying the stuffer plasmid pCW0359 form non-fluorescent colonies. The stuffer vector pCW0359 was digested with BsaI and KpnI to remove the stuffer segment and the resulting vector fragment was isolated by agarose gel purification. The sequences were designated XTEN_AD36, reflecting the AD family of motifs. Its segments have the amino acid sequence [X]3 where X is a 12mer peptide with the sequences: GESPGGSSGSES (SEQ ID NO: 270), GSEGSSGPGESS (SEQ ID NO: 271), GSSESGSSEGGP (SEQ ID NO: 272), or GSGGEPSESGSS (SEQ ID NO: 273). The insert was obtained by annealing the following pairs of phosphorylated synthetic oligonucleotide pairs:
We also annealed the phosphorylated oligonucleotide 3KpnIstopperFor: AGGTICGTCTTCACTCGAGGGTAC (SEQ ID NO: 281) and the non-phosphorylated oligonucleotide pr_3KpnIstopperRev: CCTCGAGTGAAGACGA (SEQ ID NO: 282). The annealed oligonucleotide pairs were ligated, which resulted in a mixture of products with varying length that represents the varying number of 12mer repeats ligated to one BbsI/KpnI segment. The products corresponding to the length of 36 amino acids were isolated from the mixture by preparative agarose gel electrophoresis and ligated into the BsaI/KpnI digested stuffer vector pCW0359. Most of the clones in the resulting library designated LCW0401 showed green fluorescence after induction, which shows that the sequence of XTEN_AD36 had been ligated in frame with the GFP gene and that most sequences of XTEN_AD36 had good expression levels.
We screened 96 isolates from library LCW0401 for high level of fluorescence by stamping them onto agar plate containing IPTG. The same isolates were evaluated by PCR and 48 isolates were identified that contained segments with 36 amino acids as well as strong fluorescence. These isolates were sequenced and 39 clones were identified that contained correct XTEN_AD36 segments. The file names of the nucleotide and amino acid constructs and the SEQ ID NOS for these segments are listed in Table 12.
A codon library encoding XTEN sequences of 36 amino acid length was constructed. The XTEN sequence was designated XTEN_AE36. Its segments have the amino acid sequence [X]3 where X is a 12mer peptide with the sequence: GSPAGSPTSTEE (SEQ ID NO: 359), GSEPATSGSE TP (SEQ ID NO: 360). GTSESA TPESGP (SEQ ID NO: 361), or GTSTEPSEGSAP (SEQ ID NO: 362). The insert was obtained by annealing the following pairs of phosphorylated synthetic oligonucleotide pairs:
We also annealed the phosphorylated oligonucleotide 3KpnIstopperFor: AGGTTCGTCTTCACTCGAGGGTAC (SEQ ID NO: 371) and the non-phosphorylated oligonucleotide pr_3KpnIstopperRev: CCTCGAGTGAAGACGA (SEQ ID NO: 372). The annealed oligonucleotide pairs were ligated, which resulted in a mixture of products with varying length that represents the varying number of 12mer repeats ligated to one BbsI/KpnI segment. The products corresponding to the length of 36 amino acids were isolated from the mixture by preparative agarose gel electrophoresis and ligated into the BsaI/KpnI digested stuffer vector pCW0359. Most of the clones in the resulting library designated LCW0402 showed green fluorescence after induction which shows that the sequence of XTEN_AE36 had been ligated in frame with the GFP gene and most sequences of XTEN_AE36 show good expression.
We screened 96 isolates from library LCW0402 for high level of fluorescence by stamping them onto agar plate containing IPTG. The same isolates were evaluated by PCR and 48 isolates were identified that contained segments with 36 amino acids as well as strong fluorescence. These isolates were sequenced and 37 clones were identified that contained correct XTEN_AE36 segments. The file names of the nucleotide and amino acid constructs and the SEQ ID NOS for these segments are listed in Table 13.
A codon library encoding sequences of 36 amino acid length was constructed. The sequences were designated XTEN_AF36. Its segments have the amino acid sequence [X]3 where X is a 12mer peptide with the sequence: GSTSESPSGTAP (SEQ ID NO: 447). GTSTPESGSASP (SEQ ID NO: 448), GTSPSGESSTAP (SEQ ID NO: 449), or GSTSSTAESPGP (SEQ ID NO: 450). The insert was obtained by annealing the following pairs of phosphorylated synthetic oligonucleotide pairs:
We also annealed the phosphorylated oligonucleotide 3KpnIstopperFor: AGGTTCGTCTTCACTCGAGGGTAC (SEQ ID NO: 459) and the non-phosphorylated oligonucleotide pr_3KpnIstopperRev: CCTCGAGTGAAGACGA (SEQ ID NO: 460). The annealed oligonucleotide pairs were ligated, which resulted in a mixture of products with varying length that represents the varying number of 12mer repeats ligated to one BbsI/KpnI segment The products corresponding to the length of 36 amino acids were isolated from the mixture by preparative agarose gel electrophoresis and ligated into the BsaI/KpnI digested stuffer vector pCW0359. Most of the clones in the resulting library designated LCW0403 showed green fluorescence after induction which shows that the sequence of XTEN_AF36 had been ligated in frame with the GFP gene and most sequences of XTEN_AF36 show good expression.
We screened 96 isolates from library LCW0403 for high level of fluorescence by stamping them onto agar plate containing IPTG. The same isolates were evaluated by PCR and 48 isolates were identified that contained segments with 36 amino acids as well as strong fluorescence. These isolates were sequenced and 44 clones were identified that contained correct XTEN_AF36 segments. The file names of the nucleotide and amino acid constructs and the SEQ ID NOS for these segments are listed in Table 14.
A codon library encoding sequences of 36 amino acid length was constructed. The sequences were designated XTEN_AG36. Its segments have the amino acid sequence [X]3 where X is a 12mer peptide with the sequence: GTPGSGTASSSP (SEQ ID NO: 549), GSSTPSGATGSP (SEQ ID NO: 550). GSSPSASTGTGP (SEQ ID NO: 551), or GASPGTSSTGSP (SEQ ID NO: 552). The insert was obtained by annealing the following pairs of phosphorylated synthetic oligonucleotide pairs:
We also annealed the phosphorylated oligonucleotide 3KpnIstopperFor: AGGTTCGTCTCACTCGAGGGTAC (SEQ ID NO: 561) and the non-phosphorylated oligonucleotide pr_3KpnIstopperRev: CCTCGAGTGAAGACGA (SEQ ID NO: 562). The annealed oligonucleotide pairs were ligated, which resulted in a mixture of products with varying length that represents the varying number of 12mer repeats ligated to one BbsI/KpnI segment. The products corresponding to the length of 36 amino acids were isolated from the mixture by preparative agarose gel electrophoresis and ligated into the BsaI/KpnI digested stuffer vector pCW0359. Most of the clones in the resulting library designated LCW0404 showed green fluorescence after induction which shows that the sequence of XTEN_AG36 had been ligated in frame with the GFP gene and most sequences of XTEN_AG36 show good expression.
We screened 96 isolates from library LCW0404 for high level of fluorescence by stamping them onto agar plate containing IPTG. The same isolates were evaluated by PCR and 48 isolates were identified that contained segments with 36 amino acids as well as strong fluorescence. These isolates were sequenced and 44 clones were identified that contained correct XTEN_AG36 segments. The file names of the nucleotide and amino acid constructs and the SEQ ID NOS for these segments are listed in Table 15.
XTEN_AE864 was constructed from serial dimerization of XTEN_AE36 to AE72, 144, 288, 576 and 864. A collection of XTEN_AE72 segments was constructed from 37 different segments of XTEN_AE36. Cultures of E. coli harboring all 37 different 36-amino acid segments were mixed and plasmid was isolated. This plasmid pool was digested with BsaI/NcoI to generate the small fragment as the insert. The same plasmid pool was digested with BbsI/NcoI to generate the large fragment as the vector. The insert and vector fragments were ligated resulting in a doubling of the length and the ligation mixture was transformed into BL21Gold(DE3) cells to obtain colonies of XTEN_AE72.
This library of XTEN_AE72 segments was designated LCW0406. All clones from LCW0406 were combined and dimerized again using the same process as described above yielding library LCW0410 of XTEN_AE144. All clones from LCW0410 were combined and dimerized again using the same process as described above yielding library LCW0414 of XTEN_AE288. Two isolates LCW0414.001 and LCW0414.002 were randomly picked from the library and sequenced to verify the identities. All clones from LCW0414 were combined and dimerized again using the same process as described above yielding library LCW0418 of XTEN_AE576. We screened 96 isolates from library LCW0418 for high level of GFP fluorescence. 8 isolates with right sizes of inserts by PCR and strong fluorescence were sequenced and 2 isolates (LCW0418.018 and LCW0418.052) were chosen for future use based on sequencing and expression data.
The specific clone pCW0432 of XTEN_AE864 was constructed by combining LCW0418.018 of XTEN_AE576 and LCW0414.002 of XTEN_AE288 using the same dimerization process as described above.
A collection of XTEN_AM144 segments was constructed starting from 37 different segments of XTEN_AE36, 44 segments of XTEN_AF36, and 44 segments of XTEN_AG36.
Cultures of E. coli that harboring all 125 different 36-amino acid segments were mixed and plasmid was isolated. This plasmid pool was digested with BsaI/NcoI to generate the small fragment as the insert. The same plasmid pool was digested with BbsI/NcoI to generate the large fragment as the vector. The insert and vector fragments were ligated resulting in a doubling of the length and the ligation mixture was transformed into BL21Gold(DE3) cells to obtain colonies of XTEN_AM72.
This library of XTEN_AM72 segments was designated LCW0461. All clones from LCW0461 were combined and dimerized again using the same process as described above yielding library LCW0462. 1512 Isolates from library LCW0462 were screened for protein expression. Individual colonies were transferred into 96 well plates and cultured overnight as starter cultures. These starter cultures were diluted into fresh autoinduction medium and cultured for 20-30 h. Expression was measured using a fluorescence plate reader with excitation at 395 nm and emission at 510 nm. 192 isolates showed high level expression and were submitted to DNA sequencing. Most clones in library LCW0462 showed good expression and similar physicochemical properties suggesting that most combinations of XTEN_AM36 segments yield useful XTEN sequences. 30 isolates from LCW0462 were chosen as a preferred collection of XTEN_AM144 segments for the construction of multifunctional proteins that contain multiple XTEN segments. The file names of the nucleotide and amino acid constructs and the SEQ ID NOS for these segments are listed in Table 16.
The entire library LCW0462 was dimerized as described in Example 6 resulting in a library of XTEN_AM288 clones designated LCW0463. 1512 isolates from library LCW0463 were screened using the protocol described in Example 6. 176 highly expressing clones were sequenced and 40 preferred XTEN_AM288 segments were chosen for the construction of multifunctional proteins that contain multiple XTEN segments with 288 amino acid residues.
We generated a library of XTEN_AM432 segments by recombining segments from library LCW0462 of XTEN_AM144 segments and segments from library LCW0463 of XTEN_AM288 segments. This new library of XTEN_AM432 segment was designated LCW0464. Plasmid was isolated from cultures of E. coli harboring LCW0462 and LCW0463, respectively. 1512 isolates from library LCW0464 were screened using the protocol described in Example 6. 176 highly expressing clones were sequenced and 39 preferred XTEN_AM432 segment were chosen for the construction of longer XTENs and for the construction of multifunctional proteins that contain multiple XTEN segments with 432 amino acid residues.
In parallel we constructed library LMS0100 of XTEN_AM432 segments using preferred segments of XTEN_AMI44 and XTEN_AM288. Screening this library yielded 4 isolates that were selected for further construction
The stuffer vector pCW0359 was digested with BsaI and KpnI to remove the stuffer segment and the resulting vector fragment was isolated by agarose gel purification.
We annealed the phosphorylated oligonucleotide BsaI-AscI-KpnIforP: AGGTGCAAGCGCAAGCGGCGCGCCAAGCACGGGAGGTrCGTCTFCACTCGAGGGTAC (SEQ ID NO: 717) and the non-phosphorylated oligonucleotide BsaI-AscI-KpnIrev: CCTCGAGTGAAGACGAACCTCCCGTGCTTGGCGCGCCGCTTGCGCTTGC (SEQ ID NO: 718) for introducing the sequencing island A (SI-A) which encodes amino acids GASASGAPSTG (SEQ ID NO: 719) and has the restriction enzyme AscI recognition nucleotide sequence GGCGCGCC inside. The annealed oligonucleotide pairs were ligated with BsaI and KpnI digested stuffer vector pCW0359 prepared above to yield pCW0466 containing SI-A. We then generated a library of XTEN_AM443 segments by recombining 43 preferred XTEN_AM432 segments from Example 8 and SI-A segments from pCW0466 at C-terminus using the same dimerization process described in Example 5. This new library of XTEN_AM443 segments was designated LCW0479.
We generated a library of XTEN_AM875 segments by recombining segments from library LCW0479 of XTEN_AM443 segments and 43 preferred XTEN_AM432 segments from Example 8 using the same dimerization process described in example 5. This new library of XTEN_AM875 segment was designated LCW0481.
We annealed the phosphorylated oligonucleotide BsaI-FseI-KpnIforP: AGGTCCAGAACCAACGGGGCCGGCCCCAAGCGGAGGTTCGTCTTCACTCGAGGGTAC (SEQ ID NO: 720) and the non-phosphorylated oligonucleotide BsaI-FseI-KpnIrev: CCTCGAGTGAAGACGAACCTCCGCTTGGGGCCGGCCCGTTGGTTCTGG (SEQ ID NO: 721) for introducing the sequencing island B (SI-B) which encodes amino acids GPEPTGPAPSG (SEQ ID NO: 722) and has the restriction enzyme FseI recognition nucleotide sequence GGCCGGCC inside. The annealed oligonucleotide pairs were ligated with BsaI and KpnI digested stuffer vector pCW0359 as used in Example 9 to yield pCW0467 containing SI-B. We then generated a library of XTEN_AM443 segments by recombining 43 preferred XTEN_AM432 segments from Example 8 and SI-B segments from pCW0467 at C-terminus using the same dimerization process described in example 5. This new library of XTEN_AM443 segments was designated LCW0480.
We generated a library of XTEN_AMI1318 segments by recombining segments from library LCW0480 of XTEN_AM443 segments and segments from library LCW0481 of XTEN_AM875 segments using the same dimerization process as in example 5. This new library of XTEN_AM1318 segment was designated LCW0487.
Using the several consecutive rounds of dimerization, we assembled a collection of XTEN_AD864 sequences starting from segments of XTEN_AD36 listed in Example 1. These sequences were assembled as described in Example 5. Several isolates from XTEN_AD864 were evaluated and found to show good expression and excellent solubility under physiological conditions. One intermediate construct of XTEN_AD576 was sequenced. This clone was evaluated in a PK experiment in cynomolgus monkeys and a half-life of about 20 h was measured.
Using the several consecutive rounds of dimerization, we assembled a collection of XTEN_AF864 sequences starting from segments of XTEN_AF36 listed in Example 3. These sequences were assembled as described in Example 5. Several isolates from XTEN_AF864 were evaluated and found to show good expression and excellent solubility under physiological conditions. One intermediate construct of XTEN_AF540 was sequenced. This clone was evaluated in a PK experiment in cynomolgus monkeys and a half-life of about 20 h was measured. A full length clone of XTEN_AF864 had excellent solubility and showed half-life exceeding 60 h in cynomolgus monkeys. A second set of XTEN_AF sequences was assembled including a sequencing island as described in Example 9.
Using the several consecutive rounds of dimerization, we assembled a collection of XTEN_AG864 sequences starting from segments of XTEN_AD36 listed in Example 1. These sequences were assembled as described in Example 5. Several isolates from XTEN_AG864 were evaluated and found to show good expression and excellent solubility under physiological conditions. A full length clone of XTEN_AG864 had excellent solubility and showed half-life exceeding 60 h in cynomolgus monkeys.
This example details a step in the optimization of the N-terminus of the XTEN protein to promote the initiation of translation to allow for expression of XTEN fusions at the N-terminus of fusion proteins without the presence of a helper domain. To create diversity at the codon level, seven amino acid sequences were selected and prepared with a diversity of codons. Seven pairs of oligonucleotides encoding 12 amino acids with codon diversities were designed, annealed and ligated into the NdeI/BsaI restriction enzyme digested stuffer vector pCW0551 (Stuffer-XTEN_AM875-GFP), and transformed into E. coli BL21Gold(DE3) competent cells to obtain colonies of seven libraries. The resulting clones have N-terminal XTEN 12mers fused in-frame to XTEN_AM875-GFP to allow use of GFP fluorescence for screening the expression. Individual colonies from the seven created libraries were picked and grown overnight to saturation in 500 μl of super broth media in a 96 deep well plate. The number of colonies picked ranged from approximately half to a third of the theoretical diversity of the library (see Table 17).
MASTPESGSSG
The saturated overnight cultures were used to inoculate fresh 500 (l cultures in auto-induction media in which they were grown overnight at 26° C. These expression cultures were then assayed using a fluorescence plate reader (excitation 395 nm, emission 510 nm) to determine the amount of GFP reporter present. The results indicate that median expression levels are approximately half of the expression levels with the CBD N-terminal helper domain. However, the best clones from the libraries were much closer to the benchmarks and indicate that further optimization around those sequences was warranted. It also was clear that the libraries starting with amino acids MA produced better expression than those beginning with ME. This was most apparent when looking at the best clones, which were closer to the benchmarks as they mostly start with MA. Of the 176 clones within 33% of the CBD-AM875 benchmark, 87% begin with MA, where as only 75% of the sequences in the libraries beginning with MA, a clear over representation of the clones beginning with MA at the highest level of expression. 96 of the best clones were sequenced to confirm identity and twelve sequences (see Table 18), 4 from LCW546, 4 from LCW547 and 4 from LCW552 were selected for further optimization.
This example details a step in the optimization of the N-terminus of the XTEN protein to promote the initiation of translation to allow for expression of XTEN fusions at the N-terminus of proteins without the presence of a helper domain. With preferences for the first two codons established (see Example supra), the third and fourth codons were randomized to determine preferences. Three libraries, based upon best clones from LCW546. LCW547 and LCW552, were designed with the third and fourth residues modified such that all combinations of allowable XTEN codons were present at these positions. In order to include all the allowable XTEN codons for each library, nine pairs of oligonucleotides encoding 12 amino acids with codon diversities of third and fourth residues were designed, annealed and ligated into the NdeI/BsaI restriction enzyme digested stuffer vector pCW0551 (Stuffer-XTEN_AM875-GFP), and transformed into E. coli BL21Gold(DE3) competent cells to obtain colonies of three libraries LCW0569-571. With 24 XTEN codons the theoretical diversity of each library is 576 unique clones. A total of 504 individual colonies from the three created libraries were picked and grown overnight to saturation in 500 μl of super broth media in a 96 deep well plate. This provided sufficient coverage to understand relative library performance and sequence preferences. The saturated overnight cultures were used to inoculate new 500 μl cultures in auto-induction media in which were grown overnight at 26° C. These expression cultures were then assayed using a fluorescence plate reader (excitation 395 nm, emission 510 nm) to determine the amount of GFP reporter present. The top 75 clones from the screen were sequenced and retested for GFP reporter expression versus the benchmark samples. 52 clones yielded usable sequencing data and were used for subsequent analysis. The results were broken down by library and indicate that LCW546 was the superior library. The results are presented in Table 19.
Further trends were seen in the data showing preferences for particular codons at the third and fourth position. Within the LCW569 library the glutamate codon GAA at the third position and the threonine codon ACT were associated with higher expression as seen in Table 20.
Additionally, the retest of the top 75 clones indicated that several were now superior to the benchmark clones.
This example details a step in the optimization of the N-terminus of the XTEN protein to promote the initiation of translation to allow for expression of XTEN fusions at the N-terminus of proteins without the presence of a helper domain. With preferences for the first two codons established (see Example supra), the N-terminus was examined in a broader context by combining the 12 selected 12mer sequences (see Example supra) at the very N-terminus followed by 125 previously constructed 36mer segments (see example supra) in a combinatorial manner. This created novel 48mers at the N-terminus of the XTEN protein and enabled the assessment of the impact of longer range interactions at the N-terminus on expression of the longer sequences (
The sequencing and retest also revealed several instances of independent replicates of the same sequence in the data producing similar results, thus increasing confidence in the assay. Additionally, 10 clones with 6 unique sequences were superior to the benchmark clone. They are presented in Table 22. It was noted that these were the only occurrences of these sequences and in no case did one of these sequences occur and fail to beat the bench-mark clone. These six sequences were advanced for further optimization.
This example details a step in the optimization of the N-terminus of the XTEN protein to promote the initiation of translation to allow for expression of XTEN fusions at the N-terminus of proteins without the presence of a helper domain. With preferences for the first four codons (see Examples supra, and for the best pairing of N-terminal 12mers and 36mers (see Example supra) established, a combinatorial approach was undertaken to examine the union of these preferences. This created novel 48mers at the N-terminus of the XTEN protein and enabled the testing of the confluence of previous conclusions. Additionally, the ability of these leader sequences to be a universal solution for all XTEN proteins was assessed by placing the new 48mers in front of both XTEN-AE864 and XTEN-AM875. Instead of using all 125 clones of 36mer segment, the plasmids from 6 selected clones of 36mer segment with best GFP expression in the combinatorial library were digested with NdeI/EcoRI/BsaI and the appropriate fragments were gel-purified. The plasmids from clones AC94 (CBD-XTEN_AM875-GFP) and AC104 (CBD-XTEN_AE864-GFP) were digested with digested with NdeI/EcoRI/BsaI and the appropriate fragments were gel-purified. These fragments were ligated together and transformed into E. coli BL21Gold(DE3) competent cells to obtain colonies of the libraries LCW0585 (-XTEN_AM875-GFP) and LCW0586 (-XTEN_AE864-GFP), which could also serve as the vectors for further cloning 8 selected 12mers at the very N-terminus. The plasmids of LCW0585 and LCW0586 were digested with NdeI/EcoRI/BsaI and the appropriate fragments were gel-purified. 8 pairs of oligonucleotides encoding 8 selected 12mer sequences with best GFP expression in the previous (Generation 2) screening were designed, annealed and ligated with the NdeI/EcoRI/BsaI digested LCW0585 and LCW0586 vectors, and transformed into E. coli BL21Gold(DE3) competent cells to obtain colonies of the final libraries LCW0587 (XTEN_AM923-GFP) and LCW0588 (XTEN_AE912-GFP). With a theoretical diversity of 48 unique clones, a total of 252 individual colonies from the created libraries were picked and grown overnight to saturation in 500 μl of super broth media in a 96 deep well plate. This provided sufficient coverage to understand relative library performance and sequence preferences. The saturated overnight cultures were used to inoculate new 500 μl cultures in auto-induction media in which were grown overnight at 26° C. These expression cultures were then assayed using a fluorescence plate reader (excitation 395 nm, emission 510 nm) to determine the amount of GFP reporter present. The top 36 clones were sequenced and retested for GFP reporter expression. 36 clones yielded usable sequencing data and these 36 were used for the subsequent analysis. The sequencing data determined the 12mer, the third codon, the fourth codon and the 36mer present in the clone and revealed that many of the clones were independent replicates of the same sequence. Additionally, the retest results for these clones are close in value, indicating the screening process was robust. Preferences for certain combinations at the N-terminus were seen and were consistently yielding higher fluorescence values than the benchmark controls (see Tables 23 and 24).
Notably, the preferred combination of the N-terminal for the XTEN-AM875 and the preferred combination for the XTEN-AE864 are not the same (Tables 23 and 24), indicating more complex interactions further than 150 bases from the initiation site influence expression levels. The sequences for the preferred nucleotide sequences are listed in Table 25 and the preferred clones were analyzed by SDS-PAGE to independently confirm expression. The complete sequences of XTEN_AM923 and XTEN_AE912 were selected for further analysis.
A general schema for producing and evaluating BPXTEN compositions is presented in
The general schema for producing polynucleotides encoding XTEN is presented in
DNA sequences encoding Ex4 (or another candidate BP) can be conveniently obtained by standard procedures known in the art from a cDNA library prepared from an appropriate cellular source, from a genomic library, or may be created synthetically (e.g., automated nucleic acid synthesis) using DNA sequences obtained from publicly available databases, patents, or literature references. A gene or polynucleotide encoding the Ex4 portion of the protein can be then be cloned into a construct such as those described herein, which can be a plasmid or other vector under control of appropriate transcription and translation sequences for high level protein expression in a biological system. A second gene or polynucleotide coding for the XTEN portion (in the case of
Host cells containing the XTEN-Ex4 expression vector would be cultured in conventional nutrient media modified as appropriate for activating the promoter. The culture conditions, such as temperature, pH and the like, are those previously used with the host cell selected for expression, and will be apparent to the ordinarily skilled artisan. After expression of the fusion protein, cells would be harvested by centrifugation, disrupted by physical or chemical means, and the resulting crude extract retained for purification of the fusion protein, as described below. For BPXTEN compositions secreted by the host cells, supernatant from centrifugation would be separated and retained for further purification.
Gene expression would be measured in a sample directly, for example, by conventional Southern blotting, Northern blotting to quantitate the transcription of mRNA [Thomas, Proc. Natl. Acad. Sci. USA, 77:5201-5205 (1980)], dot blotting (DNA analysis), or in situ hybridization, using an appropriately labeled probe, based on the sequences provided herein. Alternatively, gene expression would be measured by immunological of fluorescent methods, such as immunohistochemical staining of cells to quantitate directly the expression of gene product. Antibodies useful for immunohistochemical staining and/or assay of sample fluids may be either monoclonal or polyclonal, and may be prepared in any mammal. Conveniently, the antibodies may be prepared against the Ex4 sequence polypeptide using a synthetic peptide based on the sequences provided herein or against exogenous sequence fused to Ex4 and encoding a specific antibody epitope. Examples of selectable markers are well known to one of skill in the art and include reporters such as enhanced green fluorescent protein (EGFP), beta-galactosidase (i-gal) or chloramphenicol acetyltransferase (CAT).
The XTEN-Ex4 polypeptide product would be purified via methods known in the art. Procedures such as gel filtration, affinity purification, salt fractionation, ion exchange chromatography, size exclusion chromatography, hydroxyapatite adsorption chromatography, hydrophobic interaction chromatography or gel electrophoresis are all techniques that may be used in the purification. Specific methods of purification are described in Robert K. Scopes, Protein Purification: Principles and Practice, Charles R. Castor, ed., Springer-Verlag 1994, and Sambrook, et al., supra. Multi-step purification separations are also described in Baron, et al., Crit. Rev. Biotechnol. 10:179-90 (1990) and Below, et al., J. Chromatogr. A. 679:67-83 (1994).
As illustrated in
In addition, the XTEN-Ex4 fusion protein would be administered to one or more animal species to determine standard pharmacokinetic parameters, as described in Example 25.
By the iterative process of producing, expressing, and recovering XTEN-Ex4 constructs, followed by their characterization using methods disclosed herein or others known in the art, the BPXTEN compositions comprising Ex4 and an XTEN can be produced and evaluated by one of ordinary skill in the art to confirm the expected properties such as enhanced solubility, enhanced stability, improved pharmacokinetics and reduced immunogenicity, leading to an overall enhanced therapeutic activity compared to the corresponding unfused Ex4. For those fusion proteins not possessing the desired properties, a different sequence can be constructed, expressed, isolated and evaluated by these methods in order to obtain a composition with such properties.
Size exclusion chromatography analysis was performed on fusion proteins containing various therapeutic proteins and unstructured recombinant proteins of increasing length. An exemplary assay used a TSKGcl-G4000 SWXL (7.8 mm×30 cm) column in which 40 μg of purified glucagon fusion protein at a concentration of 1 mg/ml was separated at a flow rate of 0.6 ml/min in 20 mM phosphate pH 6.8, 114 mM NaCl. Chromatogram profiles were monitored using OD214 nm and OD280 nm. Column calibration for all assays were performed using a size exclusion calibration standard from BioRad; the markers include thyroglobulin (670 kDa), bovine gamma-globulin (158 kDa), chicken ovalbumin (44 kDa), equine myoglobuin (17 kDa) and vitamin B12 (1.35 kDa). Representative chromatographic profiles of Glucagon-Y288, Glucagon-Y144, Glucagon-Y72, Glucagon-Y36 are shown as an overlay in
The pharmacokinetics of GFP-L288, GFP-L576, GFP-XTEN_AF576, GFP-XTEN_Y576 and XTEN_AD836-GFP were tested in cynomolgus monkeys to determine the effect of composition and length of the unstructured polypeptides on PK parameters. Blood samples were analyzed at various times after injection and the concentration of GFP in plasma was measured by ELISA using a polyclonal antibody against GFP for capture and a biotinylated preparation of the same polyclonal antibody for detection. Results are summarized in
A fusion protein containing XTEN_AE864 fused to the N-terminus of GFP was incubated in monkey plasma and rat kidney lysate for up to 7 days at 37° C. Samples were withdrawn at time 0, Day 1 and Day 7 and analyzed by SDS PAGE followed by detection using Western analysis and detection with antibodies against GFP as shown in
The gene encoding human IL-1ra of 153aa was amplified by polymerase chain reaction (PCR) with primers 5′-ATAAAGGGTCTCCAGGTCGTCCGTCCGGTCGTAAATC (SEQ ID NO: 756) and 5′-AACTCGAAGCTTTTATTTCGTCCTCCTGGAAGTAAAA (SEQ ID NO: 757), which introduced flanking BsaI and Hindlll (underlined) restriction sites that are compatible with the BbsI and Hindlll sites that flank the stuffer in the XTEN destination vector (
Constructs were generated by replacing GFP in the XTEN destination vectors with the IL-1ra encoding fragment (
Cell Culture Production
A starter culture was prepared by inoculating glycerol stocks of E. coli carrying a plasmid encoding for IL-ra fused to AE864, AM875, or AM1296 into 100 mL 2×YT media containing 40 ug/mL kanamycin. The culture was then shaken overnight at 37° C. 100 mL of the starter culture was used to inoculate 25 liters of 2×YT containing 40 μg/mL kanamycin and shaken until the OD600 reached about 1.0 (for 5 hours) at 37° C. The temperature was then reduced to 26° C. and protein expression was induced with IPTG at 1.0 mM final concentration. The culture was then shaken overnight at 26° C. Cells were harvested by centrifugation yielding a total of 200 grams cell paste. The paste was stored frozen at −80° C. until use.
Purification of BPXTEN Comprising IL-1Ra-XTEN_AE864 or IL-1Ra-AM875
Cell paste was suspended in 20 mM Tris pH 6.8, 50 mM NaCl at a ratio of 4 ml of buffer per gram of cell paste. The cell paste was then homogenized using a top-stirrer. Cell lysis was achieved by passing the sample once through a microfluidizer at 20000 psi. The lysate was clarified to by centrifugation at 12000 rpm in a Sorvall G3A rotor for 20 minutes.
Clarified lysate was directly applied to 800 ml of Macrocap Q anion exchange resin (GE Life Sciences) that had been equilibrated with 20 mM Tris pH 6.8, 50 mM NaCl. The column was sequentially washed with Tris pH 6.8 buffer containing 50 mM, 100 mM, and 150 mM NaCl. The product was eluted with 20 mM Tris pH 6.8, 250 mM NaCl.
A 250 mL Octyl Sepharose FF column was equilibrated with equilibration buffer (20 mM Tris pH 6.8, 1.0 M Na2SO4). Solid Na2SO4 was added to the Macrocap Q eluate pool to achieve a final concentration of 1.0 M. The resultant solution was filtered (0.22 micron) and loaded onto the HIC column. The column was then washed with equilibration buffer for 10 CV to remove unbound protein and host cell DNA. The product was then eluted with 20 mM Tris pH 6.8, 0.5 M Na2SO4.
The pooled HIC eluate fractions were then diluted with 20 mM Tris pH 7.5 to achieve a conductivity of less than 5.0 mOhms. The dilute product was loaded onto a 300 ml Q Sepharose FF anion exchange column that had been equilibrated with 20 mM Tris pH 7.5, 50 mM NaCl.
The buffer exchanged proteins were then concentrated by ultrafiltration/diafiltration (UF/DF), using a Pellicon XL Biomax 30000 mwco cartridge, to greater than 30 mg/ml. The concentrate was sterile filtered using a 0.22 micron syringe filter. The final solution was aliquoted and stored at −80° C., and was used for the experiments that follow, infra.
SDS-PAGE Analysis
2 and 10 meg of final purified protein were subjected to non-reducing SDS-PAGE using NuPAGE 4-12% Bis-Tris gel from Invitrogen according to manufacturer's specifications. The results (
Analytical Size Exclusion Chromatography
Size exclusion chromatography analysis was performed using a Phenomenex BioSEP SEC S4000 (7.8×300 mm) column. 20 μg of the purified protein at a concentration of 1 mg/ml was separated at a flow rate of 0.5 ml/min in 20 mM Tris-Cl pH 7.5, 300 mM NaCl. Chromatogram profiles were monitored by absorbance at 214 and 280 nm. Column calibration was performed using a size exclusion calibration standard from BioRad, the markers include thyroglobulin (670 kDa), bovine gamma-globulin (158 kDa), chicken ovalbumin (44 kDa), equine myoglobuin (17 kDa) and vitamin B12 (1.35 kDa). A representative chromatographic profile of IL-ra-XTEN AM875 is shown in
Analytical RP-HPLC
Analytical RP-HPLC chromatography analysis was performed using a Vydac Protein C4 (4.6×150 mm) column. The column was equilibrated with 0.1% trifluoroacetic acid in HPLC grade water at a flow rate of 1 ml/min. Ten micrograms of the purified protein at a concentration of 0.2 mg/ml was injected separately. The protein was eluted with a linear gradient from 5% to 90% acetonitrile in 0.1% TFA.
Chromatogram profiles were monitored using OD214 nm and OD280 nm. A chromatogram of a representative batch of IL-ra-XTEN_AM875 is shown in
IL-1 Receptor Binding
To evaluate the activity of the IL-1ra-containing XTEN fusion proteins, an ELISA based receptor binding assay was used. Here the wells of a Costar 3690 assay plate were coated overnight with 50 ng per well of mouse IL-1 receptor fused to Fc domain of human IgG (IL-IR/Fc, R&D Systems). Subsequently the wells were blocked with 3% BSA to prevent nonspecific interactions with the solid phase. After thoroughly washing the wells, a dilution series of either IL-1ra-XTEN_AM875, XTEN_AM875-IL-1ra, or IL-1ra (anakinra) was applied to the wells. The binding reaction was allowed to proceed for 2 hr at room temperature. Unbound Il-1ra was removed by repeated washing. The bound IL-1ra ad IL-1ra-XTEn fusions were detected with a biotinylated anti-human II-1ra antibody and a horseradish peroxidase-conjugated streptavidin. The reaction was developed with TMB substrate for 20 minutes at room temperature. Color development was stopped with the addition of 0.2 N sulfuric acid. The absorbance of each well at 450 nm and 570 nm was recorded on a SpectrMax 384Plus spectrophotometer. The corrected absorbance signal (Abscorr=Abs450 nm−Abs570 nm) was plotted as a function of IL-1ra-XTEN or IL-1ra concentration to produce a binding isotherm as shown in
To estimate the binding affinity of each fusion protein for the IL-1 receptor, the binding data was fit to a sigmoidal dose-response curve. From the fit of the data an EC50 (the concentration of IL-1ra or IL-1ra-XTEN at which the signal is half maximal) for each construct was determined. As shown in
Thermal Stabilization of IL-1Ra by XTEN
In addition to extending the serum half-life of protein therapeutics, XTEN polypeptides have the property improving the thermal stability of a payload to which it is fused. For example, the hydrophilic nature of the XTEN polypeptide may reduce or prevent aggregation and thus favor refolding of the payload protein. This feature of XTEN may aid in the development of room temperature stable formulations for a variety of protein therapeutics.
In order to demonstrate thermal stabilization of IL-1ra conferred by XTEN conjugation, IL-1ra-XTEN and recombinant IL-1ra, 200 micromoles per liter, were incubated at 25° C. and 85° C. for 15 min, at which time any insoluble protein was rapidly removed by centrifugation. The soluble fraction was then analyzed by SDS-PAGE as shown in
The IL-1 receptor binding activity of IL-1ra-XTEN was evaluated following the heat treatment described above. Receptor binding was performed as described above. Recombinant IL-1ra, which was fully denatured by heat treatment, retained less than 0.1% of its receptor activity following heat treatment. However, IL-1ra-XTEN retained approximately 40% of its receptor binding activity (
The BPXTEN fusion proteins IL-1ra AE864, IL-1ra_AM875, and IL-1ra_AM1296 were evaluated in cynomolgus monkeys in order to determine in vivo pharmacokinetic parameters of the respective fusion proteins. All compositions were provided in an aqueous buffer and were administered by subcutaneous (SC) route into separate animals (n=4/group) using 1 mg/kg and/or 10 mg/kg single doses. Plasma samples were collected at various time points following administration and analyzed for concentrations of the test articles. Analysis was performed using a sandwich ELISA format. Rabbit polyclonal anti-XTEN antibodies were coated onto wells of an ELISA plate. The wells were blocked, washed and plasma samples were then incubated in the wells at varying dilutions to allow capture of the compound by the coated antibodies. Wells were washed extensively, and bound protein was detected using a biotinylated preparation of the polyclonal anti IL-1ra antibody and streptavidin HRP. Concentrations of test article were calculated at each time point by comparing the colorimetric response at each serum dilution to a standard curve. Pharmacokinetic parameters were calculated using the WinNonLin software package.
Conclusions:
The incorporation of different XTEN sequences into BPXTEN fusion proteins comprising IL-1ra results in significant enhancement of pharmacokinetic parameters for all three compositions, as demonstrated in the primate model, demonstrating the utility of such fusion protein compositions.
The BPXTEN fusion protein Ex4_AE864 was evaluated in cynomolgus monkeys in order to determine in vivo pharmacokinetic parameters of the fusion proteins after a single subcutaneous dose.
Methods:
The BPXTEN fusion protein was formulated in 20 mM Tris, pH 7.5, 135 mM NaCl at two different concentrations: 8 mg/mL and 40 mg/mL. Three groups of four monkeys (2 males and 2 females, 2-6 kg) each were dosed at 1 mg/kg (Group 1, 0.125 mL/kg), 1 mg/kg (Group 2, 0.025 mL/kg), or 5 mg/kg (Group 3, 0.125 mL/kg) via bolus injection between the skin and underlying layers of tissue in the scapular region on the back of each animal. Serial blood samples (1 ml±0.5 ml) were drawn over fourteen days from the femoral vein or artery of previously acclimated animals through a syringe with no anesthesia utilizing chair restraint. If necessary, chair restraint was utilized for a maximum of 30 minutes. All animals were fasted overnight prior to dosing and through the first 4 hours of blood sample collection (food was returned within 30 minutes following collection of the last blood sample at the 4 hour collection interval, where applicable). Each blood sample was collected into heparin plasma separator and kept on ice (2° C. to 8° C.) for approximately 5 minutes pending centrifugation. The blood samples were centrifuged (8,000×g for 5 min) and the plasma was transferred into a polypropylene tube. Plasma samples were snap frozen, and stored at approximately −70° C. until assayed. Analysis was performed using a sandwich ELISA format.
Results:
The pharmacokinetic parameters were calculated for the monkeys and the results are tabulated in Table 28. The pharmacokinetic parameters were analyzed using both a naïve pooling of all animals and using a standard two-stage analysis. The results show a difference in absorption of the fusion protein, based on dose volume administered in Group 1 versus Group 2, as evidenced by the Tmax, Cmax, AUC and volume of distribution (Vz) values. However, the calculated half-life values are comparable across the three Groups, and greatly exceed the reported terminal half-life of exenatide of 2.4 h.
Conclusions:
The linking of exendin-4 to XTEN to create a BPXTEN fusion results in significant enhancement of pharmacokinetic parameters for all three formulations, as demonstrated in the primate model, with an increase of at least 30-fold in the half-life, demonstrating the utility of such fusion protein compositions.
The effects of combination therapy of glucose regulating peptides linked to XTEN were evaluated in a mouse model of diet-induced obesity to confirm the utility of fixed combinations of monomeric fusion proteins as a single BPXTEN composition.
Methods:
The effects of combination therapy of glucagon linked to Y-288-XTEN (“Gcg-XTEN”) and exenatide linked to AE576-XTEN (“Ex4-XTEN”) or exenatide singly were tested in male C57BL/6J Diet-Induced Obese (DIO) Mice, age 10 weeks old. Mice raised on a 60% high fat diet were randomized into the treatment groups (n=10 per group) Ex4-XTEN864 (10 mg/kg IP Q2D), Ex4-XTEN864 (20 mg/kg IP Q4D). Ex4-XTEN864 (10 mg/kg IP Q2D) plus Gcg-XTEN288 (20 μg/kg IP BID), and Ex4-XTEN864 (20 mg/kg IP Q4D) plus Gcg-XTEN288 (40 μg/kg IP Q1D). A placebo group (n=10) treated with 20 mM Tris pH 7.5, 135 mM NaCl IP Q1D was tested in parallel. All groups were dosed continuously for 28 days. Body weight was monitored at regular intervals throughout the study and fasting blood glucose was measured before and after the treatment period. Groups were dosed continuously for a 28 day treatment period. Body weight was monitored continuously throughout the study and fasting blood glucose was measured before and after the treatment period, and lipid levels were determined after the treatment period.
Results:
The results are shown in
The data also show that continuous dosing for one month yielded a significant reduction in fasting blood glucose for the animals treated with Ex4-XTEN alone relative to placebo, but not for animals treated with Gcg-XTEN alone. However, animals dosed with both Gcg-XTEN and exenatide concurrently showed a statistically significantly greater reduction in fasting blood glucose levels compared to either glucose regulating peptide administered alone. Of note, the doses of Gcg-XTEN composition that resulted in the beneficial effects in combination with Ex4-XTEN were 20 and 40 μg/kg (complete fusion protein composition weight); at least 25-fold lower than the no-effect dose reported for glucagon alone in a rodent species.
Conclusions:
The data support the conclusion that combination therapy with two fusion proteins of glucose regulating peptides linked to XTEN can result in a synergistic beneficial effect over that seen with a single glucose regulating peptide such that administration of a combination composition can be tailored to reduce frequency of dosing or dosage compared to administration of a single biologic in order to reduce the threat of toxicity or unacceptable side effects.
The pharmacokinetics of Ex4-AE864 BPXTEN were determined in cynomolgus monkeys (three per group) with the BPXTEN administered by subcutaneous or intravenous injections of BPXTEN at 0.5 mg/kg over a 1 minute period. Plasma samples were collected at various time points up to 14 days after injection and analyzed by ELISA for determination of both test article serum concentration and immunogenicity. No anti-test article antibody response was observed for Ex4-AE864 in any animal after administration. Sandwich ELISA was carried out by >12 h immobilization of 100 ng capture antibody (rabbit anti-exenatide, Peninsula Laboratories, San Carlos, Calif.) to each well in a polystyrene microtiter plate (Costar 3690, Corning Inc, Corning, N.Y.), followed by blocking with 3% bovine serum albumin (BSA). After 3 washes with PBS, plasma samples were serially titrated across the plate in PBS containing 1% BSA and 0.5% Tween 20. After a 2 hour incubation and washing, the samples were probed by the addition of biotinylated IgG (rabbit anti-exenatide biotinylated in house, Peninsula Laboratories, San Carlos, Calif.) to each well. After incubation and washing, plates were developed by incubation with horseradish peroxidase-conjugated streptavidin (Thermo Fisher Scientific, Rockford, Ill.) followed by tetramethylbenzidine substrate (Neogen Corporation, Lexington, Ky.), then quenched with 0.2 N H2SO4 and read at 450 nm. Non compartmental pharmacokinetic parameters were calculated using the WinNonLin program, Version 2.1 (Pharsight Corporation. Mt. View, Calif.).
The results are depicted in
Conclusions:
It can be concluded from the results that addition of an XTEN to a glucose-regulating peptide, such as exendin-4, can greatly increase the terminal half-life compared to the peptide not linked to XTEN, and enhance other pharmacokinetic parameters, as well.
To determine the predicted pharmacokinetic profile in humans of a therapeutic protein fused to XTEN, studies were performed using exendin-4 fused to the AE864 XTEN as a single fusion polypeptide. The Ex4-XTEN construct was administered to four different animal species at 0.5-1.0 mg/kg, subcutaneously and intravenously. Serum samples were collected at intervals following administration, with serum concentrations determined using standard methods. The half-life for each species was determined, and is tabulated in Table 29. The results were used to predict the human half-life using allometric scaling of terminal half-life, volume of distribution, and clearance rates based on average body mass.
Conclusions:
It can be concluded from the results that addition of an XTEN to a glucose-regulating peptide, such as exendin-4, can greatly increase the terminal half-life compared to the peptide not linked to XTEN, and that a BPXTEN formulation with comparable half-life would permit considerably less frequent dosing than is currently employed with commercial products of glucose-regulating peptides, with dosing at weekly, every other week, or even monthly intervals.
In order to evaluate the ability of XTEN to enhance the physical/chemical properties of solubility and stability, fusion proteins of glucagon plus shorter-length XTEN were prepared and evaluated. The test articles were prepared in Tris-buffered saline at neutral pH and characterization of the Gcg-XTEN solution was by reverse-phase HPLC and size exclusion chromatography to affirm that the protein was homogeneous and non-aggregated in solution. The data are presented in Table 30. For comparative purposes, the solubility limit of unmodified glucagon in the same buffer was measured at 60 μM (0.2 mg/mL), and the result demonstrate that for all lengths of XTEN added, a substantial increase in solubility was attained. Importantly, in most cases the glucagon-XTEN fusion proteins were prepared to achieve target concentrations and were not evaluated to determine the maximum solubility limits for the given construct. However, in the case of glucagon linked to the AF-144 XTEN, the limit of solubility was determined, with the result that a 60-fold increase in solubility was achieved, compared to glucagon not linked to XTEN. In addition, the glucagon-AF144 BPXTEN was evaluated for stability, and was found to be stable in liquid formulation for at least 6 months under refrigerated conditions and for approximately one month at 37° C. (data not shown).
Conclusions:
The data support the conclusion that the linking of short-length XTEN polypeptides to a biologically active protein such as glucagon can markedly enhance the solubility properties of the protein by the resulting fusion protein, as well as confer stability at the higher protein concentrations.
The BPXTEN Ex4-AE864 was evaluated for degree of secondary structure by circular dichroism spectroscopy. CD spectroscopy was performed on a Jasco J-715 (Jasco Corporation. Tokyo, Japan) spectropolarimeter equipped with Jasco Peltier temperature controller (TPC-348WI). The concentration of protein was adjusted to 0.2 mg/mL in 20 mM sodium phosphate pH 7.0, 50 mM NaCl. The experiments were carried out using HELLMA quartz cells with an optical path-length of 0.1 cm. The CD spectra were acquired at 5°, 250, 45°, and 65° C. and processed using the J-700 version 1.08.01 (Build 1) Jasco software for Windows. The samples were equilibrated at each temperature for 5 min before performing CD measurements. All spectra were recorded in duplicate from 300 nm to 185 nm using a bandwidth of 1 nm and a time constant of 2 sec, at a scan speed of 100 nm/min. The CD spectrum shown in
Purified glucagon and exendin-3, each linked to Y288 as a BPXTEN fusion protein, were assayed for biological activity using an in vitro cell assay. Briefly, a ChemiScreen Stable Calcium Optimized glucagon receptor cell line was used for real-time calcium mobilization assays for glucagon and the glucagon-XTEN constructs, while an optimized exendin-4 receptor cell line expressing native GLP-1 receptor was used for exendin-4 and the Ex4 constructs. In this system, the cells express the native receptors and activation of this receptor results in calcium flux within the cell that can be detected using a FLIPR apparatus. As shown in
Conclusions:
The results indicate that the fusion of the glucose-regulating peptides to an unstructured recombinant protein results in compositions that retain biological activity.
The gene encoding hGH was amplified by polymerase chain reaction (PCR), which introduced NdeI and BbsI restriction sites that are compatible with the NdeI and BsaI sites that flank the stuffer in the XTEN destination vector. The pXTEN plasmid is a pET30 derivative from Novagen in the format of Stuffer-XTEN, where Stuffer can be either green fluorescent protein (GFP) or CBD and XTEN can be any length from 36 to 576 or greater. Constructs were generated by replacing a stuffer sequence in pXTEN with the hGH-encoding fragment. The pXTEN features a T7 promoter upstream of the stuffer sequence, and an XTEN sequence fused in-frame downstream of the stuffer sequence. The XTEN sequences employed belong to family XTEN_AE or XTEN_AM and encode lengths that include 36, 72, 144, 288, 576, 864, 875 and 1296 amino acids. The stuffer fragment was removed by restriction digest using NdeI and BsaI endonucleases. Restriction digested hGH DNA fragment was ligated into the cleaved pXTEN vector using T4 DNA ligase and electroporated into BL2 (DE3) Gold (Stratagene). Transformants were screened by DNA miniprep and the desired construct was confirmed by DNA sequencing. The final vector yields the hGH_XTEN gene under the control of a T7 promoter.
The gene encoding hGH was amplified by polymerase chain reaction (PCR), which introduced BbsI and HindIII restriction sites that are compatible with the BbsI and HindIII sites that flank the stuffer in the XTEN destination vector. The pCBD-XTEN plasmid is a pET30 derivative from Novagen in the format of Cellulose Binding Domain (CBD)-XTEN-Stuffer, where Stuffer is green fluorescent protein (GFP) and XTEN can be any length from 36 to 576 or greater. Constructs were generated by replacing a stuffer sequence in pCBD-XTEN with the hGH-encoding fragment. The pCBD-XTEN features a T7 promoter upstream of CBD followed by an XTEN sequence fused in-frame upstream of the stuffer sequence. The XTEN sequences employed belong to family XTEN_AE and XTEN_AM and encode lengths that include 36, 72, 144, 288, 576, 864, 875 and 1296 amino acids. The stuffer fragment was removed by restriction digest using BbsI and HindIII endonucleases. Restriction digested hGH DNA fragment was ligated into the cleaved pCBD-XTEN vector using T4 DNA ligase and electroporated into BL21(DE3) Gold (Stratagene). Transformants were screened by DNA miniprep and the desired construct was confirmed by DNA sequencing. The final vector yields the CBD_XTEN_hGH gene under the control of a T7 promoter.
The gene encoding hGH was amplified by polymerase chain reaction (PCR), which introduced BbsI and BsaI restriction sites that are compatible with the BbsI and BsaI sites that flank the stuffer in the XTEN destination vector. The pNTS-XTEN plasmid is a pET30 derivative from Novagen in the format of N-terminal XTEN expression sequence of 48 amino acids, where Stuffer is green fluorescent protein (GFP) and XTEN can be any length from 36 to 576 or greater. Constructs were generated by replacing a stuffer sequence in pCBD-XTEN with the hGH-encoding fragment. The pNTS-XTEN features a T7 promoter upstream of NTS followed by an XTEN sequence fused in-frame upstream of the stuffer sequence. The XTEN sequences employed belong to family XTEN_AE and encode lengths that include 36, 72, 144, 288, 576, 864, and 1296 amino acids. The stuffer fragment was removed by restriction digest using BbsI and BsaI endonucleases. Restriction digested hGH DNA fragment was ligated into the cleaved pNTS-XTEN vector using T4 DNA ligase and electroporated into BL21(DE3) Gold (Stratagene). In some cases, a second XTEN_AE sequence of 144 or 288 amino acids was ligated to the C-terminus of the hGH gene.
Transformants were screened by DNA miniprep and the desired construct was confirmed by DNA sequencing. The final vector yields the NTS_XTEN_hGH or NTS_XTEN_hGH_XTEN gene under the control of a T7 promoter.
Protein Expression
The plasmids described above were transformed into BL21(DE3)-Gold E. coli strain (Novagen) and plated on an LB-agar plate with the appropriate antibiotics and grown overnight at 37° C. A single colony was inoculated into 5 ml of TB125 medium and grown overnight at 37° C. The next day the inoculum was transformed into a 2 L vessel with 500 ml of TB125, and grown until an OD0.6 was reached, followed by continued growth at 26° C. for 16 hr with 0.1 mM IPTG.
Cells were collected by centrifugation and the cell pellet was resuspended in 50 ml Buffer containing 5 mM Tris pH=8.0, 100 mM NaCl. Cells were disrupted using an ultrasonic sonicator cell disruptor, and cell debris was removed by centrifugation at 15000 RPM at 4° C. The pH of the lysate was then adjusted to pH 4.5 with acetic acid to precipitate contaminating host cell proteins and was subsequently clarified by centrifugation. The clarified, acid-treated lysate was then applied to a DE52 Anion exchange chromatography column and eluted with NaCl. The eluted fraction was then further acidified to pH 4.0 and applied to a MacroCapSP cation exchange chromatography column. Product was eluted using sequential elution with NaCl.
Protein purity was estimated to be above 98%. The quantity of eluted fusion protein was determined by SDS-PAGE analysis and by measurement of total protein concentration. A high quantity of eluted fusion protein reflects higher solubility of the fusion protein relative to hGH alone.
Final Formulation and Storage
The buffer exchanged proteins were then concentrated using 10K MWCO Ultrafree concentrator to a final volume of 2 mL. The concentrate was sterile filtered using a 0.22 um syringe filter. The final solution was aliquoted and stored at −80° C.
XTEN fusions to GH were tested in a standard ELISA-based assay to evaluate their ability to bind to GH Receptor. Assays were performed using a sandwich ELISA format in which a recombinant hGH receptor (hGHR-Fc) is coated onto wells of an ELISA plate. The wells were then blocked, washed, and BPXTEN samples are then incubated in the wells at varying dilutions to allow capture of the BPXTEN. Wells were washed extensively, and bound protein was detected using a biotinylated preparation of a polyclonal or monoclonal anti-GH or anti-XTEN antibody and streptavidin HRP. The fraction of bound protein can be calculated by comparing the colorimetric response at each serum dilution to a standard curve of unmodified GH. The results, shown in
Conclusions:
The results show that the XTEN fusions retain a significant amount of receptor binding activity after fusion, with the BPXTEN fusion protein having the hGH on the C-terminus retaining more binding affinity, compared to the fusion protein having the hGH on the N-terminus.
The BPXTEN fusion proteins AE912-hGH. AM864-hGH (synonym to AM875-hGH for this and following Examples), AE912-hGH-AE144 and AE912-hGH-AE288 were evaluated in rats in order to determine in vivo pharmacokinetic parameters of the hGHXTEN polypeptides. All compositions were provided in an aqueous buffer and were administered by subcutaneous (SC) route into separate animals using 1.5 mg/kg single doses. Plasma samples were collected at various time points following administration and analyzed for concentrations of the test articles. Analysis was performed using a sandwich ELISA format. Recombinant hGHR-Fc was coated onto wells of an ELISA plate. The wells were blocked, washed and plasma samples were then incubated in the wells at varying dilutions to allow capture of the compound by the coated antibodies. Wells were washed extensively, and bound protein was detected using a biotinylated preparation of the polyclonal anti hGH antibody and streptavidin HRP. Concentrations of test article were calculated at each time point by comparing the colorimetric response at each serum dilution to a standard curve. Pharmacokinetic parameters were calculated using the WinNonLin software package.
Conclusions:
The incorporation of different XTEN sequences into fusion proteins comprising hGH results in significant enhancement of pharmacokinetic parameters for all four compositions compared to unmodified hGH, as demonstrated in the rodent model, demonstrating the utility of such fusion protein compositions. The addition of a second XTEN protein to the C-terminus of the AE-hGH constructs results in a further enhancement of the terminal half-life compared to the constructs with a single XTEN; likely due to reduced receptor mediated clearance.
BPXTEN fusion proteins containing one or two XTEN molecules (AE912-hGH, AM864-hGH, and AE912-hGH-AE144) were evaluated in cynomolgus monkeys in order to determine the effect of the inclusion of a second XTEN on in vivo pharmacokinetic parameters of the hGHXTEN polypeptides. All compositions were provided in an aqueous buffer and were administered by subcutaneous (SC) route into separate animals using 1.5 mg/kg single doses. Plasma samples were collected at various time points following administration and analyzed for concentrations of the test articles. Analysis was performed using a sandwich ELISA format. Recombinant hGHR-Fc was coated onto wells of an ELISA plate. The wells were blocked, washed and plasma samples were then incubated in the wells at varying dilutions to allow capture of the compound by the coated antibodies. Wells were washed extensively, and bound protein was detected using a biotinylated preparation of the polyclonal anti hGH antibody and streptavidin HRP. Concentrations of test article were calculated at each time point by comparing the colorimetric response at each serum dilution to a standard curve. Pharmacokinetic parameters were calculated using the WinNonLin software package. The average terminal half-life for the fusion proteins were 33 h for AM864-hGH, 44 h for AE912-hGH, and 110 h for the AE912-hGH-AE144 (containing two XTEN linked to the N- and C-termini of hGH).
Conclusions:
The incorporation of different XTEN sequences into fusion proteins comprising hGH results in significant enhancement of pharmacokinetic parameters for all three compositions, as demonstrated in the cyno model, demonstrating the utility of such fusion protein compositions, with the construct containing a second XTEN linked to the C-terminus of the hGH showing a two-fold enhancement of the terminal half-life.
The ability of the BPXTEN AM864-hGH to retain pharmacologic potency was assessed using the measured parameter of body weight gain in a hypox rat in response to administered compound.
The ability of a BPXTEN of AM864 linked to hGH to retain pharmacologic potency was assessed using the measured parameter of increase in tibial epiphyseal plate width in hypox rats.
Groups are the same as shown in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein fused to the C-terminus of FIX can be created with a XTEN release site cleavage sequence placed in between the FIX and XTEN components, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein inserted into a loop of FIX can be created, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein inserted into a loop of FIX can be created, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein inserted into a loop of FIX can be created, as depicted in
An FIX-XTEN fusion protein consisting of an XTEN protein inserted into a loop of FIX can be created, as depicted in
Variants of the foregoing Examples 41-57 can be created in which the release rate of C-terminal XTEN is altered. As the rate of XTEN release by an XTEN release protease is dependent on the sequence of the XTEN release site, by varying the amino acid sequence in the XTEN release site one can control the rate of XTEN release. The sequence specificity of many proteases is well known in the art, and is documented in several databases. In this case, the amino acid specificity of proteases would be mapped using combinatorial libraries of substrates [Harris, J. L., et al. (2000) Proc Natl Acad Sci US A, 97: 7754] or by following the cleavage of substrate mixtures as illustrated in [Schellenberger, V., et al. (1993) Biochemistry, 32: 4344]. An alternative is the identification of desired protease cleavage sequences by phage display [Matthews, D., et al. (1993) Science, 260: 1113]. Constructs would be made with variant sequences and assayed for XTEN release using standard assays for detection of the XTEN polypeptides.
An XTEN release site specific for FXI was inserted into FIX-XTEN_AE864, resulting in construct AC299. An XTEN release site specific for thrombin was inserted into FIX-XTEN_AE864 resulting in construct AC300. Construct AC296 that lacks an XTEN release site was used as a control. Expression plasmids were transfected using FuGene6 transfection reagent (Roche) into BHK-21 cells (1.2×10e6 cells in 10 ml of OptiMEM medium from Invitrogen). Medium was harvested after 4 days and concentrated 40-fold using an Amicon Ultra centrifugal filter (Ultracel_30K, Millipore) concentrator. 67 μl of concentrated medium was diluted into 10× thrombin buffer and incubated with 25 μl of immobilized thrombin (Thrombin CleanCleave Kit, RECOM-T, Sigma) for 8 hours at room temperature. The concentration of FIX in all samples was determined by ELISA using antibodies (cat # FIX-EIA, Affinity Biologicals inc. Canada). Clotting activity was determined using an aPPT assay (Thermo Scientific Pacific Hemostasis, Fisher) and activities were converted into concentrations of FIX assuming that 1 mU of FIX is equivalent to 4.5 ng/ml. Results are compiled in Table 31 below. The data show that thrombin incubation had no significant effect on ELISA signal and clotting activity of AC296 and AC299, which is consistent with the fact that both constructs lack a thrombin site. In contrast, thrombin treatment resulted in an 27-fold increase of clotting activity for AC300. Thrombin treatment restored clotting activity of AC300 to 80% of free FIX. These data demonstrate that fusion of XTEN to the C-terminus of FIX resulted in a 50- to 100-fold reduction of clotting activity. Supporting the concept of the pro-drug properties of these C-terminal FIX-XTEN constructs, proteolytic release of XTEN restored most of the clotting activity
The exon structure of proteins provides valuable information about domain boundaries that can guide the insertion of XTEN into mammalian proteins [Kolkman, J. A., et al. (2001) Nat Biotechnol, 19: 423].
Many mutants of FIX have been engineered for improved activity. Of particular utility are mutants with increased protease activity. However, mutants with improvements in Gla and/or EGF domains can be useful as well for the treatment of hemophilia B such that, after experimental or clinical evaluation, they could be used instead of the native FIX sequence. Examples of useful FIX mutants are presented in Table 7.
FIX-XTEN fusion proteins can be expressed in a variety of mammalian expression vectors. An exemplary vector pCW05090, based on pSecTag2 (Invitrogen) is illustrated in
Initial Process Capture by Anion Exchange Chromatography
Cell culture medium from cultures of the transfected cells was directly applied to 800 ml of Macrocap Q anion exchange resin (GE Life Sciences) that had been equilibrated with 20 mM Tris pH 6.8, 50 mM NaCl. The column was sequentially washed with Tris pH 6.8 buffer containing 50 mM, 100 mM, and 150 mM NaCl. The product was eluted with 20 mM Tris pH 6.8, 250 mM NaCl.
Hydrophobic Interaction Chromatography (HIC) Using Octyl Sepharose FF
A 250 mL Octyl Sepharose FF column was equilibrated with equilibration buffer (20 mM Tris pH 6.8, 1.0 M Na2SO4). Solid Na2SO4 was added to the Macrocap Q eluate pool to achieve a final concentration of 1.0 M. The resultant solution was filtered (0.22 micron) and loaded onto the HIC column. The column was then washed with equilibration buffer for 10 CV to remove unbound protein and host cell DNA. The product was then eluted with 20 mM Tris pH 6.8, 0.5 M Na2SO4.
Product Polishing by Anion Exchange Chromatography
The pooled HIC eluate fractions were then diluted with 20 mM Tris pH 7.5 to achieve a conductivity of less than 5.0 mOhms. The dilute product was loaded onto a 300 ml Q Sepharose FF anion exchange column that had been equilibrated with 20 mM Tris pH 7.5, 50 mM NaCl.
Final Formulation and Storage
The buffer exchanged proteins were then concentrated by ultrafiltration/diafiltration (UF/DF), using a Pellicon XL Biomax 30000 mwco cartridge, to greater than 30 mg/ml. The concentrate was sterile filtered using a 0.22 micron syringe filter. The final solution was aliquoted and stored at −80° C.
Codon optimization can be applied to increase expression of FIX-XTEN. This can be performed using computer algorithms that consider the codon preference in human genes, RNA structure prediction as well as the prediction of internal repeats.
XTEN can be chosen with particular properties for formulation to form depots at the injection site. This would result in slow release of FIX-XTEN from the injection site and increase the time between dosing intervals. Depot formation can be facilitated by formulating FIX-XTEN with excipients that interact with FIX-XTEN and result in complex or aggregate formation. Examples of useful excipients are zinc, protamine, PEG, polycations, polymers, polyarginine, polylysine. Depots can also be formed by loading FIX-XTEN into particles such as alginate, chitin, polylactic acid, PLGA, hyaluronic acid, hydroxyapatite or other polymers known to one of skill in the art.
Free FIX is prone to aggregation, which complicates formulation of the protein. This characteristic also prevents the development of high-concentration formulations that allow small injection volumes required for sc injection. Because of the properties of XTEN in reducing aggregation of fusion partners, compositions of FIX-XTEN can be created that 1) prevent FIX from aggregating; and 2) permit subcutaneous or intramuscular administration.
The gene encoding factor VII (“FVII”) was fused in frame to XTEN_AE864 and inserted into expression vector pCW0590. CHO-K cells were transfected with the expression vector and stable pools were selected using zeocin, and expressed protein was recovered. The amino acid sequence for the expressed Factor VII-XTEN_AE864 is listed in Table 43. Expression levels of 159 ng/ml of FVII equivalent were detected by ELISA and 214 ng/ml of FVII equivalent were detected using a PPT clotting assay (Thermo Scientific Pacific Hemostasis, Fisher). This demonstrates that fusion of XTEN_AE864 to FVII to create the BPXTEN results in a fusion protein that retains the clotting activity of FVII.
FVIIa-XTEN can be manufactured essentially as described in Example 61 for FIX-XTEN. An activation step would be added to convert FVII-XTEN into FVIIa-XTEN. Alternatively, a bicistronic vector could be utilized such that both protein chains of FVIIa are expressed separately and assemble directly into activated FVIIa-XTEN.
A standard curve was prepared by diluting normal control plasma (Pacific Hemostasis 100595) ten fold with FVII deficient plasma (100070) and then conducting 4, 5 fold serial dilutions again with factor VII deficient plasma. This created a standard curve with points at 100, 20, 4, 0.8 and 0.16 mUnits/ml of activity, where one unit of activity is defined as the amount of FVII activity in 1 ml of normal human plasma. A FVII-deficient plasma was also included to determine the background level of activity in the null plasma. The sample was prepared by adding FVII-XTEN secreted by HEK293 cells that were transiently transfected with a vector containing FVII-XTEN coding sequence in conditioned media from the cell growth, to FVII deficient plasma at a ratio of 1:10 by volume. To compensate for possible interference from the conditioned media, conditioned media from a HEK293 cells transfection with an empty vector was added in a 1:10 volume ratio to the standard curve samples. The samples were tested using a prothrombin time assay as follows. The samples were incubated at 37 C in a molecular devices plate reader spectrophotometer for 3 minutes at which point the clotting reaction was initiated by the addition of 2 volumes of thromboplastin (Dade Innovin, B4212-50) per one volume of sample. The turbidity was monitored at 405 nm for 5 minutes to create reaction profiles. The PT time, or time to onset of clotting activity, was defined as the first time where OD405 nm increased by 0.06 over baseline. A log-linear standard curve was created with the log of activity relating linearly to the PT time. From this the activity of the sample in the plate well was determined and then the activity in the sample determined by multiplying by 11 to account for the dilution into the FVII deficient plasma. Based upon duplicate measurements the activity of the FVII-XTEN fusion was 203 mUnits/ml. The reaction profiles are presented in
FVII-XTEN fusion protein can be expressed in a variety of mammalian expression vectors. Vector pCW05090 that is based on pSecTag2 (Invitrogen) is illustrated in
Initial Process Capture by Anion Exchange Chromatography.
Cell culture medium was directly applied to 800 ml of Macrocap Q anion exchange resin (GE Life Sciences) that had been equilibrated with 20 mM Tris pH 6.8, 50 mM NaCl. The column was sequentially washed with Tris pH 6.8 buffer containing 50 mM, 100 mM, and 150 mM NaCl. The product was eluted with 20 mM Tris pH 6.8, 250 mM NaCl and verified using the methods of Example 67.
Factor IX is in the intrinsic or contact activated coagulation pathway. The activity of this coagulation pathway is used to assess the activity of FIX-XTEN and proteolytic by-products using an activated partial thromboplastin time assay (aPTT). FIX activity specifically was measured as follows, a standard curve was prepared by diluting normal control plasma (Pacific Hemostasis cat#100595) two fold with FIX deficient plasma (cat#100900) and then conducting 6, 4 fold serial dilutions again with factor IX deficient plasma. This created a standard curve with points at 500, 130, 31, 7.8, 2.0, 0.5 and 0.1 mUnits/ml of activity, where one unit of activity is defined as the amount of FIX activity in 1 ml of normal human plasma. A FIX-deficient plasma was also included to determine the background level of activity in the null plasma. The sample was prepared by adding FIX-XTEN secreted by CHO cells that were transiently transfected with a vector containing FIX-XTEN coding sequence in conditioned media from the cell growth, to FIX deficient plasma at a ratio of 1:10 by volume. To compensate for possible interference from the conditioned media, conditioned media from a CHO cells transfection with an empty vector was added in a 1:10 volume ratio to the standard curve samples. The samples were tested using an aPTT assay as follows. The samples were incubated at 37 C in a molecular devices plate reader spectrophotometer for 2 minutes at which point an equal volume of aPTT reagent (Pacific Hemostasis cat#100402) was added and an additional 3 minute 37 C incubation performed. After the incubation the assay was activated by adding one volume of calcium chloride (Pacific Hemostasis cat#100304). The turbidity was monitored at 450 nm for 5 minutes to create reaction profiles. The aPTT time, or time to onset of clotting activity, was defined as the first time where OD450 nm increased by 0.06 over baseline. A log-linear standard curve was created with the log of activity relating linearly to the aPTT time. From this the activity of the sample in the plate well was determined and then the activity in the sample determined by multiplying by 11 to account for the dilution into the FIX deficient plasma.
Factor IX concentrations for the various FIX-XTEN compositions and proteolytic by-products were determined using an ELISA assay with a specific matching pair of antibodies, where the detection antibody was conjugated to HRP to simplify detection (Affinity Biologicals cat# FIX-EIA). The capture antibody was coated at 4° C. overnight on to a high binding 96 well assay plate (Corning 3690). The plate was blocked with 3% BSA in PBS for 1 hour at room temperature. The plate was washed 6 times in PBST with a plate washer. Samples or standards, diluted in PBST, were then bound into the appropriate wells for 2 hours at room temperature. The standard curve ranged from 25 ng/ml to <1 pg/ml and was prepared by serially diluting commercial FIX at a know concentration (Abcam Cat# ab62544) in PBST. The plate was again washed 6 times with PBST using a plate washer. The FIX was then detected using the detection antibody which was bound for 1 hour at 37° C. The plate was again washed 6 times with PBST using a plate washer and washed one further time with water. Signal was then developed with TMB substrate and quantified by reading at 405 nm on a molecular devices plate reader spectrophotometer. A four parameter fit is then performed on the standards and the concentration of the samples determined by comparison to the standard curve.
Clinical trials can be designed such that the efficacy and advantages of the BPXTEN compositions, relative to single biologics, can be verified in humans. For example, the BPXTEN fusion constructs comprising both glucagon and exenatide, as described in the Examples above, can be used in clinical trials for characterizing the efficacy of the compositions. The trials could be conducted in one or more metabolic diseases, disorders, or conditions that is improved, ameliorated, or inhibited by the administration of glucagon and exenatide. Such studies in adult patients would comprise three phases. First, a Phase I safety and pharmacokinetics study in adult patients would be conducted to determine the maximum tolerated dose and pharmacokinetics and pharmacodynamics in humans (either normal subjects or patients with a metabolic disease or condition), as well as to define potential toxicities and adverse events to be tracked in future studies. The study would be conducted in which single rising doses of compositions of fusion proteins of XTEN linked to glucagon and exenatide would be administered and biochemical, PK, and clinical parameters would be measured. This would permit the determination of the maximum tolerated dose and establish the threshold and maximum concentrations in dosage and circulating drug that constitute the therapeutic window for the respective components. Thereafter, clinical trials would be conducted in patients with the disease, disorder or condition.
Clinical Trial in Diabetes
A phase II dosing study would be conducted in diabetic patients where serum glucose pharmacodynamics and other physiologic. PK, safety and clinical parameters (such as listed below) appropriate for diabetes, insulin resistance and obesity conditions would be measured as a function of the dosing of the fusion proteins comprising XTEN linked to glucagon and exenatide, yielding dose-ranging information on doses appropriate for a Phase III trial, in addition to collecting safety data related to adverse events. The PK parameters would be correlated to the physiologic, clinical and safety parameter data to establish the therapeutic window for each component of the BPXTEN composition, permitting the clinician to establish either the appropriate ratio of the two component fusion proteins each comprising one glucose regulating peptide, or to determine the single dose for a monomeric BPXTEN comprising two glucose regulating peptides. Finally, a phase III efficacy study would be conducted wherein diabetic patients would be administered either the BPXTEN composition, a positive control, or a placebo daily, bi-weekly, or weekly (or other dosing schedule deemed appropriate given the pharmacokinetic and pharmacodynamic properties of the BPXTEN composition) for an extended period of time. Primary outcome measures of efficacy could include HbA1c concentrations, while secondary outcome measures could include insulin requirement during the study, stimulated C peptide and insulin concentrations, fasting plasma glucose (FPG), serum cytokine levels. CRP levels, and insulin secretion and Insulin-sensitivity index derived from an OGTT with insulin and glucose measurements, as well as body weight, food consumption, and other accepted diabetic markers that would be tracked relative to the placebo or positive control group. Efficacy outcomes would be determined using standard statistical methods. Toxicity and adverse event markers would also be followed in this study to verify that the compound is safe when used in the manner described.
Clinical Trial in Arthritis
A phase II clinical study of human patients would be conducted in arthritis patients administered BPXTEN comprising XTEN linked to IL-1ra and/or anti-IL-2, anti-CD3 or a suitable anti-inflammatory protein to determine an appropriate dose to relieve at least one symptom associated with rheumatoid arthritis, including reducing joint swelling, joint tenderness, inflammation, morning stiffness, and pain, or at least one biological surrogate marker associated with rheumatoid arthritis, including reducing erythrocyte sedimentation rates, and serum levels of C-reactive protein and/or IL2 receptor. In addition, safety data related to adverse events would be collected. A phase III efficacy study would be conducted wherein arthritis patients would be administered either the BPXTEN, a positive control, or a placebo daily, bi-weekly, or weekly (or other dosing schedule deemed appropriate given the pharmacokinetic and pharmacodynamic properties of the compound) for an extended period of time. Patients would be evaluated for baseline symptoms of disease activity prior to receiving any treatments, including joint swelling, joint tenderness, inflammation, morning stiffness, disease activity evaluated by patient and physician as well as disability evaluated by, for example, a standardized Health Questionnaire Assessment (HAQ), and pain. Additional baseline evaluations could include erythrocyte sedimentation rates (ESR), serum levels of C-reactive protein (CRP) and soluble IL-2 receptor (IL-2r). The clinical response to treatment could be assessed using the criteria established by the American College of Rheumatology (ACR), such as the ACR20 criterion; i.e., if there was a 20 percent improvement in tender and swollen joint counts and 20 percent improvement in three of the five remaining symptoms measured, such as patient and physician global disease changes, pain, disability, and an acute phase reactant (Felson, D. T., et al., 1993 Arthritis and Rheumatism 36:729-740; Felson, D. T., et al., 1995 Arthritis and Rheumatism 38:1-9). Similarly, a subject would satisfy the ACR50 or ACR70 criterion if there was a 50 or 70 percent improvement, respectively, in tender and swollen joint counts and 50 or 70 percent improvement, respectively, in three of the five remaining symptoms measured, such as patient and physician global disease changes, pain, physical disability, and an acute phase reactant such as CRP or ESR. In addition, potential biomarkers of disease activity could be measured, including rheumatoid factor, CRP, ESR, soluble IL-2R, soluble ICAM-1, soluble E-selectin, and MMP-3. Efficacy outcomes would be determined using standard statistical methods. Toxicity and adverse event markers would also be followed in this study to verify that the compound is safe when used in the manner described.
Clinical Trial in Acute Coronary Syndrome and Acute Myocardial Infarction.
A phase III trial in acute coronary syndrome (ACS) and/or acute myocardial infarction (AMI) would be conducted wherein patients diagnosed with ACS and/or AMI would be administered either a BPXTEN fusion protein comprising, for example, IL-1ra and BNP, a positive control, the combination of the BPXTEN fusion protein plus a positive control substance, or a placebo daily, bi-weekly, or weekly (or other dosing schedule deemed appropriate given the pharmacokinetic and pharmacodynamic properties of the compound) for an extended period of time. The study would be conducted to determine whether the BPXTEN is superior to the other treatment regimens for preventing cardiovascular death, non-fatal myocardial infarction, or ischemic stroke in subjects with a recent acute coronary syndrome. Patients would be evaluated for baseline symptoms of disease activity prior to receiving any treatments, including signs or symptoms of unstable angina, chest pain experienced as tightness around the chest radiating to the left arm and the left angle of the jaw, diaphoresis (sweating), nausea and vomiting, shortness of breath, as well as electrocardiogram (ECG) evidence of non-Q-wave myocardial infarction and Q-wave myocardial infarction. Additional baseline evaluations could include measurement of biomarkers, including ischemia-modified albumin (IMA), myeloperoxidase (MPO), glycogen phosphorylase isoenzyme BB-(GPBB), troponin, natriuretic peptide (both B-type natriuretic peptide (BNP) and N-terminal Pro BNP), and monocyte chemo attractive protein (MCP)-1. The clinical response to treatment could be assessed using time to first occurrence of cardiovascular death, myocardial infarction, or ischemic stroke as primary outcome measures, while occurrences of or time to first unstable angina, hemorrhagic stroke, or fatal bleeding could serve as secondary outcome measures. Efficacy outcomes would be determined using standard statistical methods. Toxicity and adverse event markers would also be followed in this study to verify that the compound is safe when used in the manner described.
Amino acid sequences can be assessed for secondary structure via certain computer programs or algorithms, such as the well-known Chou-Fasman algorithm (Chou, P. Y., et al. (1974) Biochemistry, 13: 222-45) and the Gamier-Osguthorpe-Robson, or “GOR” method (Gamier J, Gibrat J F, Robson B. (1996). GOR method for predicting protein secondary structure from amino acid sequence. Methods Enzymol 266:540-553). For a given sequence, the algorithms can predict whether there exists some or no secondary structure at all, expressed as total and/or percentage of residues of the sequence that form, for example, alpha-helices or beta-sheets or the percentage of residues of the sequence predicted to result in random coil formation.
Several representative sequences from XTEN “families” have been assessed using two algorithm tools for the Chou-Fasman and GOR methods to assess the degree of secondary structure in these sequences. The Chou-Fasman tool was provided by William R. Pearson and the University of Virginia, at the “Biosupport” internet site, URL located on the World Wide Web at .fasta.bioch.virginia.edu/fasta_www2/fasta_www.cgi?rm-misc1 as it existed on Jun. 19, 2009. The GOR tool was provided by Pole Informatique Lyonnais at the Network Protein Sequence Analysis internet site, URL located on the World Wide Web at .npsa-pbil.ibcp.fr/cgi-bin/secpred_gor4.pl as it existed on Jun. 19, 2008.
As a first step in the analyses, a single XTEN sequence was analyzed by the two algorithms. The AE864 composition is a XTEN with 864 amino acid residues created from multiple copies of four 12 amino acid sequence motifs consisting of the amino acids G, S, T, E, P, and A. The sequence motifs are characterized by the fact that there is limited repetitiveness within the motifs and within the overall sequence in that the sequence of any two consecutive amino acids is not repeated more than twice in any one 12 amino acid motif, and that no three contiguous amino acids of full-length the XTEN are identical. Successively longer portions of the AF 864 sequence from the N-terminus were analyzed by the Chou-Fasman and GOR algorithms (the latter requires a minimum length of 17 amino acids). The sequences were analyzed by entering the FASTA format sequences into the prediction tools and running the analysis. The results from the analyses are presented in Table 32.
The results indicate that, by the Chou-Fasman calculations, the four motifs of the AE family (Table 1) have no alpha-helices or beta sheets. The sequence up to 288 residues was similarly found to have no alpha-helices or beta sheets. The 432 residue sequence is predicted to have a small amount of secondary structure, with only 2 amino acids contributing to an alpha-helix for an overall percentage of 0.5%. The full-length AF864 polypeptide has the same two amino acids contributing to an alpha-helix, for an overall percentage of 0.2%. Calculations for random coil formation revealed that with increasing length, the percentage of random coil formation increased. The first 24 amino acids of the sequence had 91% random coil formation, which increased with increasing length up to the 99.77% value for the full-length sequence.
Numerous XTEN sequences of 500 amino acids or longer from the other motif families were also analyzed and revealed that the majority had greater than 95% random coil formation. The exceptions were those sequences with one or more instances of three contiguous serine residues, which resulted in predicted beta-sheet formation. However, even these sequences still had approximately 99% random coil formation.
In contrast, a polypeptide sequence of 84 residues limited to A, S, and P amino acids was assessed by the Chou-Fasman algorithm, which predicted a high degree of predicted alpha-helices. The sequence, which had multiple repeat “AA” and “AAA” sequences, had an overall predicted percentage of alpha-helix structure of 69%. The GOR algorithm predicted 78.57% random coil formation; far less than any sequence consisting of 12 amino acid sequence motifs consisting of the amino acids G, S, T, E, P, analyzed in the present Example.
Conclusions:
The analysis supports the conclusion that: 1) XTEN created from multiple sequence motifs of G, S, T, E. P, and A that have limited repetitiveness as to contiguous amino acids are predicted to have very low amounts of alpha-helices and beta-sheets; 2) that increasing the length of the XTEN does not appreciably increase the probability of alpha-helix or beta-sheet formation; and 3) that progressively increasing the length of the XTEN sequence by addition of non-repetitive 12-mers consisting of the amino acids G, S, T, E, P, and A results in increased percentage of random coil formation. In contrast, polypeptides created from amino acids limited to A, S and P that have a higher degree of internal repetitiveness are predicted to have a high percentage of alpha-helices, as determined by the Chou-Fasman algorithm, as well as random coil formation. Based on the numerous sequences evaluated by these methods, it is generally the case that XTEN created from sequence motifs of G, S, T, E, P, and A that have limited repetitiveness (defined as no more than two identical contiguous amino acids in any one motif) greater than about 400 amino acid residues in length are expected to have very limited secondary structure. With the exception of motifs containing three contiguous serines, it is believed that any order or combination of sequence motifs from Table 1 can be used to create an XTEN polypeptide of a length greater than about 400 residues that will result in an XTEN sequence that is substantially devoid of secondary structure. Such sequences are expected to have the characteristics described in the BPXTEN embodiments of the invention disclosed herein.
Polypeptide amino acid sequences can be assessed for repetitiveness by quantifying the number of times a shorter subsequence appears within the overall polypeptide. For example, a polypeptide of 200 amino acid residues has 192 overlapping 9-amino acid subsequences (or 9-mer “frames”), but the number of unique 9-mer subsequences will depend on the amount of repetitiveness within the sequence. In the present analysis, different sequences were assessed for repetitiveness by summing the occurrence of all unique 3-mer subsequences for each 3-amino acid frame across the first 200 amino acids of the polymer portion divided by the absolute number of unique 3-mer subsequences within the 200 amino acid sequence. The resulting subsequence score is a reflection of the degree of repetitiveness within the polypeptide.
The results, shown in Table 33, indicate that the unstructured polypeptides consisting of 2 or 3 amino acid types have high subsequence scores, while those of consisting of 12 amino acids motifs of the six amino acids G, S, T, E, P, and A with a low degree of internal repetitiveness, have subsequence scores of less than 10, and in some cases, less than 5. For example, the L288 sequence has two amino acid types and has short, highly repetitive sequences, resulting in a subsequence score of 50.0. The polypeptide J288 has three amino acid types but also has short, repetitive sequences, resulting in a subsequence score of 33.3. Y576 also has three amino acid types, but is not made of internal repeats, reflected in the subsequence score of 15.7 over the first 200 amino acids. W576 consists of four types of amino acids, but has a higher degree of internal repetitiveness, e.g., “GGSG” (SEQ ID NO: 782), resulting in a subsequence score of 23.4. The AD576 consists of four types of 12 amino acid motifs, each consisting of four types of amino acids. Because of the low degree of internal repetitiveness of the individual motifs, the overall subsequence score over the first 200 amino acids is 13.6. In contrast, XTEN's consisting of four motifs contains six types of amino acids, each with a low degree of internal repetitiveness have lower subsequence scores: i.e., AE864 (6.1), AF864 (7.5), and AM875 (4.5).
Conclusions:
The results indicate that the combination of 12 amino acid subsequence motifs, each consisting of four to six amino acid types that are essentially non-repetitive, into a longer XTEN polypeptide results in an overall sequence that is non-repetitive. This is despite the fact that each subsequence motif may be used multiple times across the sequence. In contrast, polymers created from smaller numbers of amino acid types resulted in higher subsequence scores, although the actual sequence can be tailored to reduce the degree of repetitiveness to result in lower subsequence scores.
TEPITOPE scores of 9mer peptide sequence can be calculated by adding pocket potentials as described by Sturniolo [Sturniolo, T., et al. (1999) Nat Biotechnol, 17: 555]. In the present Example, separate Tepitope scores were calculated for individual HLA alleles. Table 34 shows as an example the pocket potentials for HLA*0101B, which occurs in high frequency in the Caucasian population. To calculate the TEPITOPE score of a peptide with sequence P1-P2-P3-P4-P5-P6-P7-P8-P9, the corresponding individual pocket potentials in Table 34 were added. The HLA*0101B score of a 9mer peptide with the sequence FDKLPRTSG (SEQ ID NO: 800) would be the sum of 0, −1.3, 0, 0.9, 0, −1.8, 0.09, 0, 0.
To evaluate the TEPITOPE scores for long peptides one can repeat the process for all 9mer subsequences of the sequences. This process can be repeated for the proteins encoded by other HLA alleles. Tables 35-38 give pocket potentials for the protein products of HLA alleles that occur with high frequency in the Caucasian population.
TEPITOPE scores calculated by this method range from approximately −10 to +10. However, 9mer peptides that lack a hydrophobic amino acid (FKLMVWY (SEQ ID NO: 801)) in P1 position have calculated TEPITOPE scores in the range of −1009 to −989. This value is biologically meaningless and reflects the fact that a hydrophobic amino acid serves as an anchor residue for HLA binding and peptides lacking a hydrophobic residue in P1 are considered non binders to HLA. Because most XTEN sequences lack hydrophobic residues, all combinations of 9mer subsequences will have TEPITOPEs in the range in the range of −1009 to −989. This method confirms that XTEN polypeptides may have few or no predicted T-cell epitopes.
This application is a Continuation Application which claims the priority benefit of U.S. application Ser. No. 14/168,973, filed Jan. 30, 2014, now U.S. Pat. No. 9,371,369, which is a Continuation Application which claims the priority benefit of U.S. application Ser. No. 12/699,761, filed Feb. 3, 2010, now U.S. Pat. No. 8,673,860; which claims the priority benefit of U.S. Provisional application Ser. Nos. 61/149,669 filed on Feb. 3, 2009; 61/268,193, filed Jun. 8, 2009; 61/185,112, filed Jun. 8, 2009; 61/236,493, filed Aug. 24, 2009; 61/236,836, filed Aug. 25, 2009; 61/243,707, filed Sep. 18, 2009; 61/245,490, filed Sep. 24, 2009; 61/280,955, filed Nov. 10, 2009; 61/280,956, filed Nov. 10, 2009; and 61/281,109, filed Nov. 12, 2009, which are hereby incorporated herein by reference in their entirety.
This invention was made with government support under SBIR grant 2R44GM079873-02 awarded by the National Institutes of Health. The government has certain rights in the invention.
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