Development of a GMP-compliant assay for antibody concentration

A validated Biacore assay for determining the concentration of a monoclonal antibody intended for the treatment of prostate cancer was optimized within three months. The antibody was captured on a sensor surface after initial immobilization of protein A, serving as the IgG-specific binding molecule. Immobilization, surface regeneration, and sensor chip storage were all investigated and the optimal conditions for the final assay were determined.

A total of 26 concentration assays were run on different days using four different sensor chips. Inter-assay variability was below 10% at the highest concentration of the antibody tested
(Data courtesy of Birgit Vetter, Susanne Schade, Dr Thomas Urbig and Dr Frank Hanakam at Micromet AG, Munich, Germany)