Hydrophilic Interaction Chromatography Hyphenated with Mass Spectrometry: A Powerful Analytical Tool for the Comparison of Originator and Biosimilar Therapeutic Monoclonal Antibodies at the Middle-up Level of Analysis.

The development and approval processes of biosimilar mAbs depend on their comparability to originators. Therefore, analytical comparisons are required to assess structural features and post-translational modifications (PTM) and thereby minimize the risk of being clinically meaningful differences between biosimilar and originator drug products. The glycosylation pattern of mAbs is considered to be an important critical quality attribute (CQA), and several analytical approaches have been proposed that facilitate characterizing and monitoring a glycosylation profile, albeit mainly at a glycan and glycopeptide level of analysis. In this study, we demonstrate the utility of hydrophilic interaction chromatography (HILIC) hyphenated with mass spectrometry (MS) for the qualitative profiling of glycosylation patterns at the protein level, by comparing originator and biosimilars mAbs (Remicade/Remsina/Inflectra, Herceptin/Trastuzumab B, and Erbitux/Cetuximab B) using a middle-up approach. We demonstrate the ability of HILIC to resolve hydrophilic variants of protein biopharmaceuticals at the middle-up level of analysis, its complementarity to reversed phase liquid chromatography, and its hyphenation to MS. HILIC features combined to MS make a powerful analytical tool for the comparison of originator and biosimilar mAbs that could eventually be applied in routine analyses for quality control.