IL-7 drug substance, composition, preparation and uses
The present invention relates, generally, to the fields of immunology and molecular biology. The invention discloses, more particularly, new and improved interleukin-7 drug substances, corresponding specific immunoreactive antibodies, as well as compositions comprising the same, their preparation and uses. The invention also discloses methods to characterize the impurity profile of a r-hIL-7 drug substance used for therapeutic purpose, as well as optimized nucleotide sequences encoding mammalian IL-7, recombinant expression vectors and methods for preparing and purifying said polypeptides. The present invention stems from the unexpected discovery that the long term activity of recombinant IL-7 is mostly expressed by a specific conformer and that other conformers, potential product-related substances, product-related impurities, and process-related impurities, which would normally be included in the specification of the drug substance and/or drug product, although bioactive, should be strictly minimized because they are able to trigger an immune reaction against the desired IL-7 molecule.
1. A composition of matter comprising a human or simian IL-7 conformer, wherein said conformer comprises the following three disulfide bridges: Cys: 1-4 (Cys2-Cys92); 2-5 (Cys34-Cys129) and 3-6 (Cys47-Cys141), wherein the total amount by weight of said IL-7 conformer in said composition of matter is at least 98% by weight and wherein said composition of matter is substantially free of IL-7 molecular variants or product related impurities.
2. The composition of matter according to claim 1 , wherein said IL-7 conformer is a recombinant human IL-7 conformer that is not immunogenic in humans.
3. The composition of matter according to claim 2 , wherein said IL-7 conformer comprises SEQ ID NO: 2.
4. The composition of matter according to claim 1 , wherein said IL-7 conformer is a recombinant simian IL-7 conformer that is not immunogenic in non-human primates.
5. The composition of matter according to claim 4 , wherein said IL-7 conformer comprises amino acids 26-177 of SEQ ID NO: 13.
6. The composition of matter according to claim 1 , wherein said IL-7 conformer is not glycosylated.
7. The composition of matter according to claim 1 , wherein said IL-7 conformer is glycosylated.
8. The composition of matter according to claim 1 , wherein said IL-7 conformer is associated to the hepatocyte growth factor as a heterodimer.
9. The composition of matter according to claim 1 , wherein said IL-7 conformer is functionally attached to a Fc portion of an IgG heavy chain through a peptide hinge region, said IgG being a human IgG1 or IgG4.
10. The composition of matter according to claim 1 , wherein said IL-7 conformer is functionally associated to a Human Serum Albumin (HSA) or a portion of HSA as a fusion protein.
11. The composition of matter according to claim 1 , wherein said composition of matter is substantially free of another IL-7 conformer.
12. The composition of matter according to claim 1 , wherein the total amount by weight of IL-7 in said composition of matter is at least 99.5% by weight.
13. A pharmaceutical composition comprising an effective amount of a human or simian IL-7 conformer, wherein said conformer comprises the following three disulfide bridges: Cys: 1-4 (Cys2-Cys92); 2-5 (Cys34-Cys129) and 3-6 (Cys47-Cys141), wherein at least 98% of the total amount by weight of IL-7 consists of said conformer and wherein said composition is substantially free of IL-7 molecular variants or product related impurities, and one or more pharmaceutically acceptable carriers.
14. The pharmaceutical composition according to claim 13 , wherein the pharmaceutically acceptable carrier is selected from the group consisting of sucrose, trehalose and an amino acid.
15. The pharmaceutical composition according to claim 14 , wherein the pharmaceutically acceptable carrier is contained in an appropriate buffer to form an isotonic solution.
16. The pharmaceutical composition according to claim 15 , wherein said appropriate buffer has a pH range of between 5 to 7.5.
17. The pharmaceutical composition according to claim 16 , wherein said appropriate buffer is an organic salt selected from a sodium citrate buffer or an ammonium acetate buffer.
18. The pharmaceutical composition according to claim 13 , wherein said composition is a lyophilized form.
19. The pharmaceutical composition according to claim 13 , wherein said composition further comprises a protein or a surfactant.
20. The pharmaceutical composition according to claim 13 , further comprising an immuno-stimulating agent selected from a hematopoietic cell growth factor, a cytokine, an antigen, an adjuvant, or a combination thereof.
21. The pharmaceutical composition according to claim 20 , wherein said hematopoietic cell growth factor is selected from the group consisting of Stem Cell Factor (SCF), the soluble form of the SCF, G-CSF, GM-CSF, Flt-3 ligand, IL-15 and IL-2.
22. The pharmaceutical composition according to claim 20 , wherein the cytokine is selected from the group consisting of γ interferon, IL-2, IL-12, RANTES, B7-1, MIP-2 and MIP-1α.
23. The pharmaceutical composition according to claim 20 , wherein said antigen is selected from the group consisting of a synthetic or natural peptide, a recombinant protein, a killed, inactivated or attenuated pathogen product, a lipid, a portion thereof and a combination thereof.
24. The pharmaceutical composition according to claim 23 , wherein said antigen is selected from the group consisting of antigens derived from HIV, Varicella Zoster virus, Influenza virus, Epstein Barr virus, type I or 2 Herpes Simplex virus, human cytomegalovirus, Dengue virus, Hepatitis A, B, C or E virus, Respiratory Syncytium virus, human papilloma virus, mycobacterium tuberculosis, Toxoplasma and Chlamydia.
25. The pharmaceutical composition according to claim 20 , wherein said adjuvant is selected from any substance, mixture, solute or composition facilitating or increasing the immunogenicity of an antigen and able to induce a Th1-type immune response.
26. The pharmaceutical composition according to claim 13 , wherein the effective amount of said IL-7 conformer is between about 3 to 300 μg/kg/day.
27. A method of producing an IL-7 drug substance as defined in claim 1 , the method comprising:
a) providing a sample comprising IL-7 polypeptides,
b) purifying an IL-7 conformer which comprises the following three disulfide bridges: Cys: 1-4 (Cys2-Cys92); 2-5 (Cys34-Cys129)and 3-6 (Cys47-Cys141) to produce an IL-7 drug substance, and
c) measuring or quantifying, in the drug substance, said IL-7 conformer.
28. The method according to claim 27 , wherein said sample is obtained from a culture of recombinant prokaryotic or eukaryotic host cells producing IL-7 polypeptides.
29. The method according to claim 28 , wherein said sample is or derives from a culture of prokaryotic host cells encoding an IL-7 polypeptide and further wherein the method further comprises, prior to step b):
i) treating said sample to cause a complete denaturation of said IL-7 polypeptides,
ii) purifying the denatured polypeptide obtained in step i) and
iii) refolding the polypeptides.
30. The method according to claim 29 , wherein step i) comprises the dissolution of inclusion bodies in a denaturant buffer.
31. The method according to claim 29 , wherein step ii) is performed by hydrophobic chromatography, ion-exchange or inverse phase chromatography.
32. The method according to claim 31 , wherein said hydrophobic chromatography is implemented using HIC butyl.
33. The method according to claim 29 , wherein step ii) is carried out at a pH comprised between 6 and 9.
34. The method according to claim 27 , wherein said purification step b) comprises the performance of an affinity chromatography.
35. The method according to claim 34 , wherein said affinity chromatography is performed on a column of sulfated polysaccharides.
36. The method according to claim 35 , wherein the sulfated polysaccharide is dextran sulfate or heparin.
37. The method according to claim 27 , wherein the IL-7 conformer is characterized in the drug substance by Mass spectrometry, infra-red spectroscopy, NMR, by determining circular dichroism, by measuring the affinity toward a specific monoclonal antibody raised against said IL-7 conformer, or heparin affinity chromatography, and measured or quantified by ELISA, bioassay or the affinity of said IL-7 conformer for IL-7 receptor or a method of protein quantification.
38. The method according to claim 28 , wherein IL-7 expression by the recombinant host cells is inducible, regulated or transient, so that the cell culture and IL-7 expression phases can be dissociated.
39. The composition of matter according to claim 1 , wherein said IL-7 conformer is a human IL-7 conformer that is not immunogenic in humans.
40. The composition of matter according to claim 1 , wherein said IL-7 conformer is a simian IL-7 conformer that is not immunogenic in non-human primates.
41. The pharmaceutical composition according to claim 13 , wherein said IL-7 conformer is a human IL-7 conformer that is not immunogenic in humans.
42. The pharmaceutical composition according to claim 13 , wherein said IL-7 conformer is a simian IL-7 conformer that is not immunogenic in non-human primates.