What is the patent expiry date for Keytruda?

Keytruda, also known as pembrolizumab, is a monoclonal antibody used in the treatment of various types of cancer. The patent for pembrolizumab has been a subject of ongoing modifications since its initial patent filing.

The United States Patent and Trademark Office lists several patents related to pembrolizumab, and the expiry date for these patents vary [1].

According to the patent database, the original patent for pembrolizumab (U.S. Patent No. 8,233,356) expired in September of 2022, about 20 years after the initial filing date [1].

However, the manufacturer, Bristol-Myers Squibb, has filed multiple follow-up patents for pembrolizumab, which extend the patent protection for the medication [1].

DrugPatentWatch.com reports that the patent for pembrolizumab 100 mg injectable solution, for instance, is set to expire in March of 2038, while other formulations or compositions may have different expiry dates [2].

Please note that the patent expiry dates may change over time due to various factors, such as re-examination or patent modifications. The latest information available from the sources may provide more accurate insights.

Sources:

[1] United States Patent and Trademark Office: "U.S. Patent No. 8,233,356: Monoclonal antibody and method for treating cancer" (accessed April 20, 2026)

[2] DrugPatentWatch.com: "Patent details for pembrolizumab (Keytruda)" (accessed April 20, 2026)