Antibody-drug conjugates (ADCs) add an additional level of challenge to testing of biotherapeutics. Besides the antibody, which needs to be evaluated for potential and known mechanisms of action (MoA), there is a cytostatic compound conjugated that alters the behavior of the antibody-vehicle within the typical assays. Therefore, characterization of new innovators as well as biosimilarity assessment is even more challenging than it is for antibody therapeutics. Using the example of Trastuzumab emtansine, Charles River has set up a panel of…