Composition comprising antibody that binds to domain II of HER2 and acidic variants thereof

1. A method of making a pharmaceutical composition comprising: (1) preparing a composition comprising a main species HER2 antibody that binds to domain II of HER2 and comprises variable light and variable heavy amino acid sequences set forth in SEQ ID Nos. 3 and 4, respectively, and acidic variants thereof comprising disulfide reduced variant, and (2) determining the acidic variants in the composition, and confirming that the amount thereof is less than about 25%.

2. The method of claim 1 wherein step (2) further comprises identifying the disulfide reduced variant comprised in the acidic variants by non-reduced capillary electrophoresis with sodium dodecyl sulfate (CE-SDS).

3. The method of claim 1 wherein step (2) comprises determining the acidic variants by ion exchange chromatography.

4. The method of claim 3 which comprises cation exchange chromatography using a cation exchanger with a carboxylate functional group.

5. The method of claim 4 wherein the conditions for the chromatography comprise: Buffer A, 20 mM BisTris, pH 6.0; Buffer B, 20 mM BisTris, 200 mM NaCl, pH 6.0; and a gradient of 0.5% Buffer B at 1.0 mL/min.

6. The method of claim 1 comprising combining the composition after step (2) with a pharmaceutically acceptable carrier.

7. The method of claim 1 wherein the composition determined in step (2) is in a pharmaceutically acceptable carrier.

8. The method of claim 1 wherein the acidic variants further comprise glycated variant of the main species antibody.

9. The method of claim 1 wherein the acidic variants further comprise non-reducible variant of the main species antibody.

10. The method of claim 1 wherein the acidic variants further comprise sialylated variant of the main species antibody.

11. The method of claim 1 wherein the acidic variants further comprise deamidated variant of the main species antibody.

12. The method of claim 1 wherein the acidic variants further comprise glycated variant, deamidated variant, sialylated variant, and non-reducible variant of the main species antibody.

13. The method of claim 12 wherein the glycated variant, deamidated variant, disulfide reduced variant, sialylated variant, and non-reducible variant constitute at least 75 to 80% of the acidic variants in the composition.

14. The method of claim 1 wherein the main species HER2 antibody comprises light chain and heavy chain amino acid sequences set forth in SEQ ID Nos. 15 and 16, respectively.

15. The method of claim 1 wherein the disulfide reduced variant has one or more reduced interchain disulfide bonds and is detectable by non-reduced CE-SDS.

16. The method of claim 15 wherein the disulfide reduced variant comprises 1% to 6% of the composition measurable by non-reduced CE-SDS.

17. The method of claim 1 wherein the composition further comprises an amino acid-terminal leader extension of the main species antibody, wherein the amino-terminal leader extension comprises or consists of VHS-.

18. The method of claim 1 wherein the composition further comprises an amino acid sequence variant of the main species HER2 antibody selected from the group consisting of an antibody comprising a C-terminal lysine residue on one or both heavy chains thereof, and an antibody with one or more oxidized methionine residues.

19. The method of claim 1 wherein the composition is expressed by and recovered from a Chinese Hamster Ovary cell line expressing the main species HER2 antibody.

20. A method of making a pharmaceutical composition comprising: (1) preparing a composition comprising a main species HER2 antibody that binds to domain II and comprises light chain and heavy chain amino acid sequences set forth in SEQ ID Nos. 15 and 16, respectively, and acidic variants thereof comprising disulfide reduced variant which has one or more reduced interchain disulfide bonds, and (2) determining acidic variants in the composition, wherein the amount of disulfide reduced variant comprises 1% to 6% of the composition measurable by non-reduced CE-SDS.

21. The method of claim 20 comprising combining the composition after step (2) with a pharmaceutically acceptable carrier.

22. The method of claim 20 wherein the composition determined in step (2) is in a pharmaceutically acceptable carrier.

23. The method of claim 20 wherein the acidic variants further comprise glycated variant of the main species antibody.

24. The method of claim 20 wherein the acidic variants further comprise non-reducible variant of the main species antibody.

25. The method of claim 20 wherein the acidic variants further comprise sialylated variant of the main species antibody.

26. The method of claim 20 wherein the acidic variants further comprise deamidated variant of the main species antibody.

27. The method of claim 20 wherein the acidic variants further comprise glycated variant, deamidated variant, sialylated variant, and non-reducible variant of the main species antibody.

28. The method of claim 27 wherein the glycated variant, deamidated variant, disulfide reduced variant, sialylated variant, and non-reducible variant constitute at least 75 to 80% of the acidic variants in the composition.

29. The method of claim 20 wherein the composition further comprises an amino acid-terminal leader extension of the main species antibody, wherein the amino-terminal leader extension comprises or consists of VHS-.

30. The method of claim 20 wherein the composition further comprises an amino acid sequence variant of the main species HER2 antibody selected from the group consisting of an antibody comprising a C-terminal lysine residue on one or both heavy chains thereof, and an antibody with one or more oxidized methionine residues.

31. The method of claim 20 wherein the composition is expressed by and recovered from a Chinese Hamster Ovary cell line expressing the main species HER2 antibody.