Bioanalytical Challenges in Support of Complex Modalities of Antibody-Based Therapeutics

Antibody-based therapeutic classes are evolving from monoclonal antibodies to antibody derivatives with complex structures to achieve advanced therapeutic effect. These antibody derivatives may contain multiple functional domains and are often vulnerable to in vivo biotransformation. Understanding the pharmacokinetics of these antibody derivatives requires a sophisticated bioanalytical approach to carefully characterize the whole drug and each functional domain with respect to quantity, functionality enabled by biotransformation, and corresponding immune responses. Ligand binding assays and liquid chromatography-mass spectrometry assays are predominantly used in bioanalytical support of monoclonal antibodies and are continuously used for antibody derivatives such as antibody drug conjugate and bispecific antibodies. However, they become increasingly cumbersome in coping with increased complexity of drug modality and associated biotransformation. In this mini-review, we examined the current pharmacokinetic assays in the literature for antibody drug conjugate and bispecific antibodies, and presented our view of promising bioanalytical technologies to address the distinct bioanalytical needs of complex modalities.