Bioanalytical challenges of biosimilars.

Biologics such as monoclonal antibodies and recombinant proteins represent a significant portion of the pharmaceutical market. With many of the first generation biologics' patents expiring, an increasing number of biosimilars will be submitted for approval in the near future. The successful development of a biosimilar requires the demonstration of biosimilarity in terms of efficacy, safety and purity to an innovator-approved product. While regulatory frameworks have been established for the approval of biosimilars in several countries, there is not an established guidance for bioanalytical testing of biosimilars. Although there are regulatory guidances and White Papers on testing requirements for biologics in general, there is a need to address the bioanalytical challenges and solutions that apply specifically to the analysis of biosimilars in biological samples. This paper will focus on components of the PK and immunogenicity assays that are critical to biosimilar drug development.