Purification process of recombinant monoclonal antibodies with mixed mode chromatography

• Monoclonal antibody purification was set up without the use of protein A.
• Purification was based on 2 mixed mode resins followed by a membrane polishing step.
• The overall purification yield was 88%, with 99.9% purity and 15 ppm residual HCPs.

An innovative process to purify mAb from CHO cell culture supernatant was developed. This three-step process involved two mixed mode resins and an anion exchange membrane. We used a human IgG mixture to determine the optimal conditions for each purification step. Thereafter, the whole process was evaluated and improved for the purification of a recombinant mAb produced in the supernatant of CHO cells. Once optimized, yield and purity of 88% and 99.9%, respectively were comparable to those obtained in a conventional process based on a capture step using protein A. In addition, aggregates, HCPs and DNA levels in the purified fraction were below regulatory specifications. Then we used mass spectrometry to identify contaminating proteins in the antibody fraction in order to highlight the behavior of HCPs.