Claims for Patent: 8,840,877

Summary for Patent: 8,840,877

Title:	Polysaccharide-protein conjugates reversibly coupled via imine bonds
Abstract:	Method for preparing an oxidized polysaccharide-protein composition, by (a) oxidizing a polysaccharide with an oxidizing agent to form an oxidized polysaccharide where less than 20% of the oxidized units are comprised of alpha-hydroxy aldehyde units, (b) reacting the oxidized polysaccharide with a protein to form a composition comprising an oxidized polysaccharide-protein conjugate, and (c) maintaining the oxidized polysaccharide-protein conjugate composition by placing it in an environment where the temperature is less than 8.degree. C. The oxidized polysaccharide and the protein are conjugated via one or more imine bonds, the oxidized polysaccharide-protein composition is soluble in aqueous solvent, and the composition is capable of releasing the protein.
Inventor(s):	Adamson; Gord (Mississauga, CA), Bell; David (Mississauga, CA), Brookes; Steven (Mississauga, CA)
Assignee:	Therapure Biopharma Inc. (Mississauga, Ontario, CA)
Application Number:	12/999,076
Patent Claims:	1. A method of preparing an oxidized polysaccharide-protein composition comprising the steps of: (a) oxidizing a polysaccharide with an alkali metal periodate compound to form an oxidized polysaccharide where less than 20% of the oxidized units are comprised of alpha-hydroxy aldehyde units; (b) reacting the oxidized polysaccharide with a protein in the absence of a reducing agent to form a composition comprising an oxidized polysaccharide-protein conjugate, (c) subjecting the oxidized polysaccharide-protein conjugate to dialysis; (d) subjecting the dialyzed polysaccharide-protein conjugate to sterile filtration to allow for administration to a human or animal; the oxidized polysaccharide and the protein being conjugated via one or more imine bonds which are not subjected to reduction; the oxidized polysaccharide-protein composition being soluble in aqueous solvent; the composition being capable of releasing the protein. 2. A method according to claim 1, wherein the polysaccharide is selected from cellulose, pectin, starch and hydroxyhydrocarbyl derivatives thereof. 3. A method according to claim 1, wherein the polysaccharide is selected from cellulose, pectin, starch, hydroxyalkyl cellulose and hydroxyalkyl starch. 4. A method according to claim 1, wherein the polysaccharide is hydroxyethyl starch. 5. A method according to claim 1, wherein the degree of oxidation of the oxidized polysaccharide is from 1 to 100%. 6. A method according to claim 1, wherein the weight average molecular weight of the polysaccharide is from 1 to 2000 kDa. 7. A method according to claim 1, wherein the ratio of oxidized polysaccharide to protein is from 0.1:1 to 20:1. 8. A method according to claim 1, wherein the oxidized polysaccharide is reacted with a protein in step (b) in the presence of at least one further protein such that the oxidized polysaccharide-protein composition comprises more than one protein and each protein is conjugated to the oxidized polysaccharide via one or more imine bonds. 9. A method according to claim 1, wherein the or each protein is selected from antibodies, cytokines, enzymes, growth factors and regulatory proteins. 10. A method according to claim 1, wherein the or each protein is selected from erythropoietin (EPO), granulocyte-colony stimulating factor (G-CSF), uricase, beta-glucocerebrosidase, alpha-galactosidase, C-1 inhibitor, streptokinase, DNAseI, alpha-1 antitrypsin, asparaginase, arginine deiminase, Factor IX, Factor VIIa, Factor VIII, Factor IIa (thrombin), anti-TNF-alpha antibody, tissue plasminogen activator, human growth hormone, superoxide dismutase, catalase, CD163 antibody, anti-VEGF, anti-thrombin antibody, anti-CD20 antibody, anti-IgG1 antibody, anti-HER2 antibody, anti-CD33 antibody, anti-IgG2a antibody, anti-EGFR antibody, histone, interferon, insulin, albumin and mixtures thereof. 11. A method according to claim 1, wherein the oxidized polysaccharide-protein conjugate is less than 0.1 .mu.m in size. 12. A method according to claim 1, wherein the protein has a weight average molecular weight of greater than about 1 kDa. 13. A method according to claim 1, wherein the oxidized polysaccharide is reacted with a protein in step (b) in the absence of a molecular crowding agent. 14. A method according to claim 1, wherein the oxidized polysaccharide-protein composition further comprises nonconjugated protein. 15. A method of reversibly conjugating a protein to an oxidized polysaccharide comprising the steps of preparing an oxidized polysaccharide-protein composition according to claim 1, and dissolving the oxidized polysaccharide-protein composition in a solvent. 16. A method according to claim 1, wherein the polysaccharide has less than 15% 1,2,3-triol content. 17. A method according to claim 1 wherein the polysaccharide has less than 5% 1,2,3-triol content. 18. A method according to claim 1 wherein the polysaccharide has less than 1% 1,2,3-triol content. 19. A method according to claim 1, wherein the ratio of oxidized polysaccharide to protein is 1:1 molar equivalents of polysaccharide relative to protein. 20. A method according to claim 1, wherein the ratio of oxidized polysaccharide to protein is 0.1:1 molar equivalents of polysaccharide relative to protein. 21. A method according to claim 1, wherein the ratio of oxidized polysaccharide to protein is 10:1 molar equivalents of polysaccharide relative to protein. 22. A method according to claim 1, wherein the degree of oxidation of the oxidized polysaccharide is 100%. 23. A method according to claim 1, wherein step (b) is carried out at a pH of 6-8. 24. A method according to claim 1, wherein step (a) is carried out at a temperature of less than 20.degree. C. and step (b) is carried out at a temperature of at least 5.degree. C.

Details for Patent 8,840,877

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Recordati Rare Diseases, Inc.	ELSPAR	asparaginase	For Injection	101063	01/10/1978		2028-06-26