Keytruda biosimilars near FDA review, but payer dynamics and low uptake loom
- The FDA accepted Formycon's FYB206, the first publicly disclosed Keytruda biosimilar filing, in October 2026; approval could come as early as Q3 2027, ahead of key patent expiries starting in 2028.
- Zydus will commercialize FYB206 in the US and Canada, and the FDA reportedly agreed a pathway without a comparative phase 3 efficacy trial; about a dozen other candidates are in development.
- Obstacles include uncertainty over which of Keytruda's 30-plus indications will be covered, PBM formulary preference for high-rebate brands, and biosimilar share still under 20%; Keytruda earned Merck $31.7 billion in 2025.
💡 Points Based on public reports
A skipped comparative phase 3 lowers the cost of entering, but it does nothing for the harder problem: Merck's rebate leverage with PBMs. Biosimilar share under 20% suggests price cuts alone don't move formularies. Watch the label scope FDA grants FYB206 and whether Zydus pairs it with an aggressive net-price or private-label PBM arrangement.
Keytruda biosimilars are coming — but they face an uphill battle ↗