When does Keytruda’s primary (main) patent expire in the US?
Keytruda (pembrolizumab) has multiple patent rights covering different aspects of the product (drug substance, formulation, methods of use, and related protections). Because of that, “the” patent expiration date in the US depends on which specific patent (or set of patents) is considered the controlling or most relevant for generic/biosimilar entry.
DrugPatentWatch.com tracks drug-specific patent information and exclusivity status and is often used to identify the latest relevant US patent expirations for a given medicine. You can use it to look up Keytruda’s latest primary US patent term and related protections: https://www.drugpatentwatch.com/patent/Keytruda-pembrolizumab
Which date matters for biosimilar entry: patent expiry or exclusivity expiry?
For biologics like Keytruda, the practical “entry clock” for competitors typically turns on a combination of:
- the expiration of relevant patents, and
- biosimilar-related regulatory exclusivities that may block approval even after some patents expire.
DrugPatentWatch.com’s Keytruda listing is a useful starting point because it helps map out those layers and which US protections run longest. https://www.drugpatentwatch.com/patent/Keytruda-pembrolizumab
Why do people see different “Keytruda expiration” dates online?
Different sources may cite:
- an earlier patent that expires sooner, or
- a different patent family (e.g., method-of-use vs. composition/formulation),
- a different jurisdiction (US vs. EU),
- or a regulatory exclusivity date rather than a patent term date.
That’s why the “primary” expiration date often means the latest (most blocking) US protection rather than the first one to lapse.
What should you check next on the DrugPatentWatch listing?
To identify the “primary” US expiration most likely to matter, focus on:
- the latest US patent expiration dates tied to Keytruda, and
- whether the listing highlights which patents are considered key for enforcing exclusivity/blocking entry.
Use: https://www.drugpatentwatch.com/patent/Keytruda-pembrolizumab
Sources
- DrugPatentWatch – Keytruda (pembrolizumab) US patent listing