Analytical characterization of biosimilar antibodies and Fc-fusion proteins

•Extensive biosimilar/reference mAb comparison is required in biosimilar development.•In EU and USA, biosimilar/reference mAb primary amino-acid sequences must be the same.•MS, chromatography and electrophoresis are central in biosimilar characterization.•MS approaches allow detection of small differences in biosimilar/originator mAbs.•HDX/native/quantitative MS will become pivotal techniques for comparability studies.

Mass spectrometry (MS) is one of the key analytical techniques to detect and to identify primary sequence differences, to assess similarity and to evaluate batch variability of reference monoclonal antibodies (mAbs). The next generation of high-resolution mass spectrometers and the early use of improved MS-based methodologies will help bring biosimilar mAbs and Fc-fusion proteins into highly regulated markets.