First Keytruda Biosimilar Under FDA Review: Formycon/Zydus' FYB206 Accepted Without a Comparative Phase 3 Trial — Decision Expected Q3 2027
October 13, 2026. Formycon AG and Zydus Lifesciences announced that the FDA accepted for review the BLA for FYB206, their proposed pembrolizumab (Keytruda) biosimilar — "to the best of their knowledge... the first publicly announced FDA acceptance of an application for a Keytruda biosimilar." Formycon submitted the BLA in Q3 2026; under the biosimilar user-fee clock, "a decision could be expected in the third quarter of 2027." A Health Canada dossier is also filed.
The notable part is how it got there. In February 2025, Formycon agreed with FDA that FYB206 would not require a comparative Phase 3 efficacy trial — long standard for monoclonal-antibody biosimilars, typically taking one to three years and hundreds of patients. Development instead relied on "a comprehensive analytical and functional comparability package and the pivotal Dahlia pharmacokinetic (PK) study," which met its primary objective in February 2026. Formycon says skipping the Phase 3 "will save investments in the high double-digit million euro range." CEO Stefan Glombitza: "We developed FYB206 on a path agreed with the FDA, without conducting a comparative Phase III efficacy trial. This enabled us to accelerate the program and substantially reduce development investment while maintaining the rigorous scientific standards required for biosimilar approval."
The market it targets: Keytruda is the world's best-selling biologic — "Worldwide sales of Keytruda, including the subcutaneous formulation Keytruda Qlex, reached USD 31.7 billion in 2025. Combined sales totaled USD 16.4 billion in the first half of 2026." Zydus, which holds US/Canada commercialization rights under a December 2025 licensing deal, pays Formycon a milestone on acceptance. Zydus managing director Sharvil P. Patel: "Acceptance of the application marks a significant step toward expanding access to affordable pembrolizumab therapy in the US and Canada."
Why it matters: this is the first visible product of FDA's October 2025 draft guidance proposing that comparative efficacy studies can be dropped when analytical comparability is strong — now applied to the biggest drug in oncology. If FYB206 is approved on the Q3 2027 timeline, it sets up biosimilar pricing pressure on Keytruda well ahead of the 2028 US loss of exclusivity, and other pembrolizumab programs (mAbxience's BENITO trial, Cipla/Qilu's QL2107 Phase 3) took the more expensive route.