Rapid Assessment of Molecular Similarity between a Candidate Biosimilar and an Innovator Monoclonal Antibody Using Complementary LC-MS Methods

There is an emerging interest in developing biosimilar monoclonal antibodies (MAbs). To avoid expensive clinical trials and shorten time to market, the biosimilar industry must establish that a developing product is, as much as possible, similar to a marketed innovator product through comprehensive analysis. Here, we demonstrate that ultra high pressure liquid chromatography (UHPLC) and mass spectrometry (MS) can be used routinely to characterize minor differences between a candidate biosimilar and an innovator IgG1 MAb. A two amino acid residue variance in the heavy chain sequence was detected by LC-MS intact protein mass measurement and located by tryptic peptide mapping with data independent acquisition LC-MS Microheterogeneities due to N-linked glycosylation and chemical degradation were comprehensively catalogued and compared. The results show that complementary LC MS methods can be used as a set of routine tools for rapid comparison of molecular similarity between a candidate biosimilar and a commercially available MAb.