Formycon and Zydus announced that the FDA accepted the Biologics License Application for FYB206, a proposed biosimilar to Keytruda. According to the companies, this is the first publicly announced FDA acceptance of a Keytruda biosimilar application.
The program proceeded without a comparative Phase III efficacy trial following an FDA-agreed development pathway established in February 2025.
Instead, the evidence package relies on extensive analytical and functional comparability testing and the pivotal DAHLIA pharmacokinetic study, which the companies reported met its primary objective in February 2026.
The companies anticipate a regulatory decision in Q3 2027, although FDA acceptance for review does not establish that the product will ultimately be approved. Formycon AG
Primary sources: Formycon and Zydus announcement, October 13 · FDA biosimilar development guidance
Why it matters strategically
The financial implications could be substantial.
Formycon estimates that omitting the comparative Phase III efficacy trial could save development expenditure in the high double-digit millions of euros.
That is a company estimate, not an independently verified saving.
The more important implication is structural.
Traditional biosimilar development frequently involved large comparative efficacy trials requiring substantial patient recruitment, clinical operations, and monitoring.
The FDA's October 2025 draft guidance describes circumstances in which such trials may not be necessary when other evidence adequately supports biosimilarity. The guidance remains a draft and is not a universal waiver.
