Biotherapeutics and Bioanalytical Techniques

As many of therapeutic biologics (including monoclonal antibodies and antibody-drug conjugates) enter the frontline of disease treatment, tracking their stability in vivo, is a critical step in development of these therapeutics. Unstable antibody therapeutics (including unstable antibody-drug conjugates) may cause decreased drug activity, fast clearance, increased immunogenicity, and safety issues (toxicities). Non enzyme-mediated deamidation is a common protein degradation that normally occurs on asparagine (and to a lesser extent, glutamine residues), resulting in a conversion to aspartic and isoaspartic

acids with a mass shift of +0.984 Da. To monitor the deamidation of therapeutic antibodies dosed in vivo, we developed analytical methods with the combination of immunoassay and LC/MS using peptide level MS detection. We further optimized the process and established an automated high throughput method allowing for high fi delity deamidation analysis of human

antibodies from in vivo study samples. Similarly, we were also able to characterize the stability of antibody-drug conjugates in vivo, by using the combination of affi nity-capture and intact protein MS analysis. Th ese procedures will help to exclude unstable drug candidates at early development phase, and select stable antibody-based therapeutics for clinical applications.