Evaluation of Biosimilarity Based on an Empirical Bayes Method

Biosimilars have received much attention from sponsors and regulatory authorities while patents on many biological products had expired recently or will soon expire in the next few years. According to the definition of biosimilar product from the European Medicines Agency’s guidance and the U.S. Food and Drug Administration’s guidelines, biosimilar should be highly similar, not identical, to the innovative biological product. In this research, we focus on establishing posterior criterion to assess the biosimilarity between the biosimilar product and the innovator product. We consider the prior information of the reference product and a non-informative prior to build the mixture empirical prior information of the biosimilar product. We further construct a posterior criterion to check the biosimilarity between the reference product and the biosimilar product. If the posterior probability of the similarity criterion is higher or equal to a pre-specified level, the biosimilarity between the reference product and the biosimilar product will be concluded. The statistical properties of the proposed approach are discussed through numerical results in different scenarios. A real example is provided to illustrate applications of the proposed approach.