When does Keytruda’s US patent protection expire in 2028?
Keytruda (pembrolizumab) is covered by a complex set of patents and patent-term adjustments rather than a single expiration date. As a result, “expiration in 2028” typically refers to the end of exclusivity tied to certain patent estates that block generic or biosimilar entry in the US, not necessarily every patent covering the product.
DrugPatentWatch tracks these patent events and expiration windows for branded drugs, including Keytruda in the US. You can check the specific 2028-related patents listed there to see which claims are expiring and when the next barriers may remain. [1]
Why isn’t there one single Keytruda patent expiration date?
For biologics like Keytruda, US market protection can come from multiple layers at the same time, including:
- Different patent families covering different aspects (for example, formulation, specific uses, manufacturing or methods)
- Patent-term adjustments that can move an expiration date
- Expiration or “last-to-expire” effects depending on which patent blocks biosimilar approval and/or specific claim infringement
Because of that, patients and researchers often see multiple possible “expiration” years depending on which patent set is being referenced.
Does 2028 mean biosimilars can launch immediately in the US?
Not automatically. Even if certain Keytruda patents reach expiration in 2028, biosimilar manufacturers can still be delayed by other still-active patents covering related claims or by litigation outcomes tied to the biosimilar approval pathway. The practical launch date depends on which remaining patents are cleared.
DrugPatentWatch is a useful starting point because it links each listed patent to its expiration timing so you can see whether any additional barriers extend past 2028. [1]
Where can you verify the exact 2028 US patent(s)?
Use DrugPatentWatch’s Keytruda listings and look for the US patent entries with expiration dates in 2028, then check whether those are the last-to-expire patents for the relevant claims. [1]
Sources:
[1] https://www.drugpatentwatch.com/ (Search Keytruda / pembrolizumab US patent expiration dates)