On 9 March 2026, the FDA issued a new draft guidance on biosimilar development and the BPCIA aimed at reducing upfront research and development timelines and costs for biosimilar developers and lowering the cost of medicines for consumers. In the new draft guidance, FDA “recommended streamlining unnecessary clinical pharmacokinetic (PK) testing when scientifically justified” stating that “this change could save biosimilar developers up to 50% of their PK study costs, or approximately $20 million, and help lower drug costs.”
The new draft guidance, New and Revised Draft Q&As on Biosimilar Development and the BPCI Act (Revision 4) revises and replaces the earlier draft of the guidance (Revision 3) issued in 2021. It includes revisions to certain Q&As that appeared in a previous version of the final guidance entitled Questions and Answers on Biosimilar Development and the BPCI Act. The new draft is open for public comments until 11 May 2026.
Under the proposed guidelines, clinical data from a comparator product approved outside of the US could be used to demonstrate similarity to the US licensed reference product. In certain circumstances, this would eliminate the need for an additional three-way PK study, with international clinical data satisfying the FDA.
The new draft guidance removes the previous recommendation for biosimilar developers to conduct at least one clinical PK study directly comparing their proposed biosimilar with the US licensed reference product. Instead, when “scientifically justified”, developers may rely on a non-licensed US comparator product to demonstrate biosimilarity.
The FDA has already begun allowing companies to streamline clinical trial requirements in the US on a case-by-case basis through feedback sessions. For example, in February 2025, Formycon/Zydus announced the early termination of the Ph 3 trial for biosimilar pembrolizumab after the FDA was satisfied with relying on clinical data from Phase 1 trial (“Dahlia”), combined with “a comprehensive analytical program” to support regulatory review.
The FDA also formally withdrew its 2015 final guidance, Scientific Considerations in Demonstrating Biosimilarity to a Reference Product, as the document no longer reflects the agency’s current thinking or expectations.