Keytruda Biosimilar First to Enter U.S. Review... "Starting Gun" Fires in KRW 40 Trillion Market Race

Biosimilar competition for the world's highest-grossing cancer drug gains momentum
German company Formycon's product accepted for FDA review
Samsung Bioepis and Celltrion also in the race

Competition among biosimilars of Keytruda, the world’s highest-grossing immuno-oncology drug, is gathering momentum. A biosimilar developed by Germany’s Formycon has become the first to enter the U.S. regulatory review process, accelerating the race for a market worth around KRW 40 trillion ahead of the expiration of a key patent on the original drug in 2028.

According to the Korea Biotechnology Industry Organization (KoreaBIO) and industry sources on October 14, Formycon and India’s Zydus Lifesciences announced on October 13 local time that the U.S. Food and Drug Administration (FDA) had accepted for review the biologics license application (BLA) for FYB206, a Keytruda biosimilar candidate. The companies said this was the first publicly announced acceptance of an FDA application for a Keytruda biosimilar.

Formycon and Zydus signed an exclusive licensing and supply agreement for FYB206 in the United States and Canada in December 2025. Formycon is responsible for development, regulatory submissions, and product supply. The application was submitted in the third quarter of 2026. The FDA aims to complete its review within 12 months of a biosimilar application’s submission. This includes up to 60 days for filing review and 10 months for the substantive review. The FYB206 application was also submitted to Health Canada.

Keytruda, whose active ingredient is pembrolizumab, is sold by U.S.-based MSD. It is an immune checkpoint inhibitor that blocks the PD-1 receptor on immune cells and is used to treat multiple types of cancer. Global sales last year, including sales of Keytruda Qlex, a subcutaneous formulation, reached USD 31.6 billion (approximately KRW 42.4388 trillion), while sales in the first half of 2026 totaled USD 16.4 billion (approximately KRW 22.0252 trillion).

FYB206 entered regulatory review without a comparative Phase 3 efficacy trial. In February 2025, Formycon reached an agreement with the FDA that the trial would not be required, and proceeded with development focused on analytical and functional comparability data and pharmacokinetic studies. In February 2026, the “Dahlia” study confirmed pharmacokinetic equivalence with the reference drug, and clinical development was completed in July 2026.

In South Korea, Samsung Bioepis and Celltrion are developing Keytruda biosimilars. Last month, Pharmint, a Singapore-based pharmaceutical supply chain company, cited information from Australian intellectual property law firm Pearce IP and named Formycon, Samsung Bioepis, and Celltrion as development frontrunners. Amgen and Sandoz are also involved in development, and at least 13 companies are working on related products.

Keytruda’s key U.S. substance patent expires in December 2028, while patents covering its manufacturing and use methods remain in effect until May and November 2029, respectively. The substance patent in South Korea expires in June 2028, while key patents in major European markets are set to expire in 2031 and those in Japan in 2032-2033. MSD expects biosimilar competition to intensify in 2028-2029.

Meanwhile, the Keytruda biosimilars currently in development target the intravenous formulation. The U.S. patent for Keytruda Qlex, the subcutaneous formulation sold by MSD, expires in 2043. MSD expects 30-40% of future demand for Keytruda to treat solid tumors to shift to Qlex.

This content was produced with the assistance of AI translation services.