FDA accepts first Keytruda biosimilar application as Merck faces looming patent cliff

The U.S. Food and Drug Administration has accepted the first publicly announced filing for a Keytruda biosimilar, identified as FYB206, which could receive approval as early as the third quarter of 2027.

Merck’s flagship cancer therapy is approaching a patent cliff, with key expirations slated for 2028, and roughly a dozen other biosimilar candidates are currently in development.

Industry analysts note that branded drug makers often secure strategic agreements with pharmacy benefit managers and other supply‑chain players, creating financial incentives that favor the original product and potentially limiting biosimilar uptake.

Keytruda generated $31.7 billion in sales for Merck in 2025, so the entry of biosimilars could reshape revenue streams if they can overcome these market barriers.