Christina Satterwhite: “There are many challenges to consider when developing and validating bioanalytical assays for biosimilar drug development. Acquiring multiple lots of the originator from the US and EU can be difficult. Ideally, the same lots used in the clinical trials would be needed for the assays in sufficient quantity to support all clinical sample analysis. In addition, the actual concentration of the originator drugs is needed in the assays to achieve a direct comparison to the biosimilar drug. Inventory of the critical reagents is key during the course of the biosimilar development program so that changes in critical reagents do not add to the variability in the data set over time.”
Jonathan St-Germain: “Because of the complexity of biological therapeutics, a major challenge, in most cases, is the requirement for a multi-faceted approach to obtain sufficiently comprehensive data in order to legitimately conclude on biosimilarity. For example, the level of biosimilarity of a therapeutic monoclonal antibody will not only depend on its amino acid sequence similarity, but also on post-translational modifications including (but not limited to) glycosylation, which can greatly affect the structure and function of such a molecule. For these reasons, comprehensive characterization and valid quantification of biological therapeutics is seldom (if ever) achieved using a single platform.”
Paul Declerck: “The real challenge in biosimilar drug development is not in determining whether differences exist with the reference product, but whether these differences may or may not have an impact on the safety or efficacy profile. In other words, are the observed bioanalytical differences expected to have a clinical impact, or not? Therefore, the bioanalytical comparability exercise should cover all the structural and functional characteristics to assess biosimilarity.”
Arno Kromminga: “The formulation and consequently aggregation are key factors for biosimilar drug development as these factors dictate the bioanalysis and the immunogenicity results.”
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