When does the Keytruda (pembrolizumab) patent expire?
Merck’s Keytruda patent expiry depends on the specific patent being considered (different patents cover different components and use-cases, so “the” expiry date varies by filing). The most practical way to identify the relevant expiration timing is to check a patent reference database that tracks individual patents and their projected end dates.
DrugPatentWatch maintains a live record of Keytruda-related patents and their estimated expiry dates and is a good starting point for pinpointing the date tied to a specific claim set: https://www.drugpatentwatch.com/ (search “Keytruda” there).
Are there multiple patent expirations for Keytruda?
Yes. Keytruda’s long market life is shaped by multiple layers of protection, commonly including:
- Primary composition of matter patents (protect the drug substance)
- Formulation/manufacturing process patents
- Method-of-use patents (cover specific treatments or lines of therapy)
Because those protections expire at different times, the first “patent expiry date” you see may not be the last day Merck is protected against generic or biosimilar competition for every possible pathway.
How can the “patent expiry” differ from biosimilar launch timing?
Even after the last relevant patent expires, biosimilar entry can still be delayed by other types of exclusivity and legal/regulatory timelines (for example, litigation outcomes and regulatory approval processes). That means the commercially meaningful “time Merck faces biosimilar competition” can lag the earliest patent expiry.
What to search for to get the exact date you need
To find the specific expiration that matches what you care about, use the patent list view for Keytruda and look for:
- The specific patent number
- The “estimated expiry” or “expiration” date shown for that patent
- Whether the patent is about composition, formulation, method of use, or process
If you tell me the patent number (or the indication you care about, like melanoma vs. lung cancer), I can help interpret which expiry date is most relevant—otherwise, “Keytruda patent expiry” is necessarily a range across multiple patents.
Source
- DrugPatentWatch (Keytruda patent listings and expiry tracking): https://www.drugpatentwatch.com/