Optimizing biosimilar development: current approaches to demonstrating pharmacokinetic and analytical similarity and a proposal for a single reference approach

Many biosimilars have been approved in both the United States of America (U.S.A.) and European Union (EU). We aim to highlight how regulatory challenges and divergent requirements between both agencies exist. A comprehensive review of biosimilars approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) was conducted. We aimed to highlight similarities and differences in approaches taken by the agencies regarding the use of non-local (i.e. non -US and non-EU) reference medicinal products in biosimilar development. A search of the six most frequent classes of biosimilars authorized (cutoff date: 12 June 2024) by these agencies were identified and their public assessment reports reviewed. The review highlighted that pharmacokinetic (PK) bioequivalence studies are often replicated, the current process is inefficient and not entirely necessary when critical quality attributes are considered. This article provides a comparative analysis of biosimilar approvals in EU and US regulatory agencies, focusing on non-local reference medicinal product (RMP) utilization and bioequivalence demonstration. The findings contribute to literature on biosimilar development and regulatory considerations, enhancing understanding of harmonization opportunities in biosimilar approval processes, potentially improving global access to high-quality, cost-effective biosimilars.