On October 13, 2026, Formycon and Zydus announced the FDA accepted for review their aBLA for FYB206 (pembrolizumab), a proposed biosimilar of Merck’s Keytruda^® (pembrolizumab).  This is the first publicly disclosed aBLA for a Keytruda^® biosimilar.  According to the press release, FYB206 was developed without a comparative Phase 3 efficacy trial, following a development pathway agreed upon with the FDA.

On October 20, 2026, Formycon and Zydus filed PGR2027-00003 against Merck and Agilent’s U.S. Patent No. 12,529,702 (“the ’702 patent”), challenging the claims under § 101 as unpatentable subject matter, under § 103 as obvious, and under § 112 as lacking enablement.  The ’702 patent is directed to methods for determining the eligibility of a subject having a malignancy for treatment with an anti-PD therapeutic agent.  This is the first patent dispute filed relating to a Keytruda^® biosimilar.

Merck reported $31.6 billion in worldwide Keytruda^® sales in 2025.

For more information about these and other biosimilars and biosimilar patent disputes, please visit BiologicsHQ.

 

_____________________________________________________

The author would like to thank April Breyer Menon for her contributions to this article.