The first Keytruda biosimilar has reached the FDA. Formycon and Zydus Lifesciences announced on October 13 that the agency accepted the biologics licence application for FYB206, a proposed biosimilar to Merck pembrolizumab, which the companies say is the first publicly announced acceptance of a Keytruda biosimilar filing. The application was submitted in the third quarter of 2026, and under the Biosimilar User Fee Amendments review clock a decision could come in the third quarter of 2027. A dossier has also been submitted to Health Canada.
The programme reached filing on a streamlined path. In February 2025 Formycon agreed with the FDA that FYB206 would not require a comparative Phase 3 efficacy trial, and in February 2026 its Dahlia study met its primary objective by showing pharmacokinetic equivalence to pembrolizumab in the adjuvant melanoma setting. Germany based Formycon develops and will supply the product and receives a milestone payment triggered by the acceptance. India based Zydus, its partner since December 2025, will commercialise in the United States and Canada, subject to approval and to resolution of intellectual property issues.
The prize is the largest in the industry. Keytruda, including its subcutaneous Qlex form, sold 31.7 billion dollars in 2025, and key patent expirations begin in 2028. About a dozen biosimilar candidates are in development, according to PharmaVoice, and an estimated 118 biologic medicines representing about 232 billion dollars of sales stand to lose patent protection by 2034, on IQVIA figures cited there.
Approval is not the same as uptake, and that is the core of the October 30 PharmaVoice analysis. Biosimilars hold below 20 percent market share in the United States despite more than 85 approvals, because branded manufacturers, pharmacy benefit managers and other intermediaries have deals that can favour the established product. The analysis argues that even a cheaper, faster development path, of the kind FYB206 used, will not translate into lower system costs unless formulary incentives change, and that if buyers do not switch, developers will stop investing in the next wave. FYB206 is therefore a test case twice over: for a no Phase 3 development route, and for whether the first Keytruda copy can take share once it is allowed to sell.