Biophysical Characterization and Stability Testing for Antibody Drug Conjugates

Sponsored by Waters Corporation

Aggregation and stability issues in bioconjugates can go undetected until late in development if biophysical characterization is delayed until stability studies. Deanna Hunt, Senior Director of Business Development at KBI Biopharma, highlights how her team deploys analytical ultracentrifugation (AUC) early to verify size-exclusion chromatography (SEC) methods are accurately capturing aggregation and cross-checking results against stressed and long-term stability samples. She highlights additional techniques used to study aggregates and stability, including differential scanning calorimetry (DSC) to monitor shifts in melting temperature within the antibody’s CH2 region, dynamic light scattering (DLS) to track conformational changes during drug loading, and emerging interest in mass photometry and ion mobility. Melting temperature broadening becomes more pronounced at higher drug-to-antibody ratio (DAR) due to increased molecular heterogeneity. Host cell protein testing remains important early on because of polysorbate-related issues with monoclonal antibodies. Lance Cadang, Scientist, Synthetic Molecule Analytical Chemistry at Genentech, adds that as some programs shift from lyophilized to liquid formulations, confirming conjugation integrity and DAR consistency through a product’s shelf life has become an important stability consideration.