Claims for Patent: 7,927,815

Summary for Patent: 7,927,815

Title:	Protein purification method
Abstract:	A method for removing contaminant DNA in a sample containing a physiologically active protein, which comprises the following steps: 1) converting the sample containing a physiologically active protein into a neutral aqueous solution of low conductivity; and 2) removing the resulting particles.
Inventor(s):	Takeda; Kozo (Tokyo, JP), Ochi; Norimichi (Tokyo, JP)
Assignee:	Chugai Seiyaku Kabushiki Kaisha (Tokyo, JP)
Application Number:	12/018,688
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 7,927,815
Patent Claims:	1. A method for removing contaminant DNA in a sample containing a physiologically active protein, which comprises the following steps: 1) converting the sample containing a physiologically active protein into an acidic aqueous solution of low conductivity of 300 mS/m or less and having a molarity of 100 mM or less at pH of 1.5 to 3.9; 2) adjusting the pH of the resulting sample from step (1) to pH of 4 to 8 to form particles, wherein the molarity of the adjusted sample is 100 mM or less; and 3) removing the particles thereby to remove contaminant DNA in the sample. 2. The method according to claim 1, wherein the acidic aqueous solution of low conductivity has a molarity of 50 mM or less. 3. The method according to claim 1, wherein the acidic aqueous solution of low conductivity has an ionic strength of 0.2 or less. 4. The method according to claim 1, wherein the acidic aqueous solution is selected from the group consisting of aqueous solutions of hydrochloric acid, citric acid and acetic acid. 5. The method according to claim 1, wherein the contaminant DNA is present at a DNA concentration of 22.5 pg/ml or less in the treated sample containing a physiologically active protein. 6. The method according to claim 1, wherein the physiologically active protein is an antibody. 7. The method according to claim 6, wherein the antibody is a humanized monoclonal antibody. 8. The method according to claim 7, wherein the antibody is a humanized anti-IL-6 receptor antibody. 9. The method according to claim 7, wherein the antibody is a humanized anti-HM1.24 antigen monoclonal antibody. 10. The method according to claim 7, wherein the antibody is a humanized anti-parathyroid hormone-related peptide antibody (anti-PTHrP antibody). 11. The method according to claim 7, wherein the antibody is a humanized anti-tissue factor antibody. 12. The method according to claim 1, wherein the particles are removed by filtration through a filter. 13. A method for removing contaminant DNA in a sample containing a physiologically active protein, which comprises: 1) converting the sample containing a physiologically active protein into an acidic aqueous solution of low conductivity of 300 mS/m or less and having a molarity of 100 mM or less at pH of 1.5 to 3.9; 2) neutralizing the pH of the resulting sample from step (1) by addition of a buffer to raise the pH to a neutral level to form particles, wherein the molarity of the neutralized sample is 100 mM or less; and 3) filtering the resulting sample from step (2) to remove particles containing contaminant DNA.

Details for Patent 7,927,815

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Nps Pharmaceuticals, Inc.	NATPARA	parathyroid hormone	For Injection	125511	01/23/2015		2021-03-09