A consistency approach for evaluation of biosimilar products.

Recently, biosimilars have attracted much attention from sponsors and regulatory authorities, while patents on early biological products will soon expire in the next few years. The European Medicines Agency (EMEA) of the European Union (EU) published a guideline on similar biological medicinal products for approval of these products in 2005 . Based on the foundational principles of the EMEA guideline, biosimilars are expected to be similar, not identical, to the innovator biologics they seek to copy. In this article, we develop a consistency approach for assessment of similarity between a biosimilar product and the innovator biologic. A method for sample size determination for conducting a clinical trial to assess the biosimilar product is also proposed. A numerical example is given to illustrate applications of the proposed approach in different scenarios.