Biosimilarity assessment of biosimilar therapeutic monoclonal antibodies

The concept of biosimilar was established in the early 2000s in EU. Currently, the regulatory framework for biosimilar has also been established in the US, Japan, and other countries. As of 2018, biosimilars for infliximab, adalimumab, rituximab, trastuzumab, and bevacizumab have been approved. During the development of a biosimilar, product quality should be evaluated and compared with those of the reference product extensively. Among the quality attributes of therapeutic antibodies, FcRn binding and related structures are well known to affect the pharmacokinetic profile of the product. Other quality attributes such as antigen binding, glycan structure, and isoelectric point are considered to have a potential impact on the pharmacokinetic profile of the product. Based on the high similarity of the quality attributes of the biosimilar to those of its reference product, comparative non-clinical and clinical studies are conducted. Comparable pharmacokinetic profile of the biosimilar and the reference product is important for biosimilar evaluation. In this review, the basic concept of biosimilar development as well as pharmacokinetic data obtained via non-clinical and clinical studies of biosimilar therapeutic antibody is introduced, and future perspective is discussed.