Fractionation of Bispecific Antibody Charge Variants by MauriceFlex and their Identification by Mass Spectrometry

This study characterizes charge variant differences between Mosunetuzumab-axgb (Lunsumio) and a research-grade biosimilar using the MauriceFlex™ instrument, which separates charge variants, mobilizes them, and enables charge variant fraction collection. Individual charge variant peak fractions were digested with IdeS (FabRICATOR®) and analyzed by mass spectrometry at the subunit level to identify the modifications contributing to the charge variant profile.