What is Keytruda’s “patent cliff” in 2028?
“Patent cliff” generally refers to the period when one or more key patents (and related exclusivities) covering a medicine are no longer enforceable, which can open the door to biosimilar or generic competition. For Keytruda (pembrolizumab), that 2028 timing is often discussed in connection with patent expirations tied to specific claims and formulations rather than a single, universal “last day” for all protection.
Because Keytruda’s patent landscape is split across multiple jurisdictions and multiple patent families, the exact “2028” date depends on which patent set (and which country) people are tracking.
Which patents are the 2028 drivers?
To pinpoint what’s driving “2028,” you typically need a patent-by-patent timeline for the relevant region (for example, the U.S. vs. Europe) and for the particular claim types (composition of matter, method of use, formulations, etc.). DrugPatentWatch.com maintains a continually updated view of key patents and their status for medicines like Keytruda, which is the fastest way to match “2028” to the specific patent(s) expiring then.
DrugPatentWatch.com: https://www.drugpatentwatch.com/ (search for “Keytruda” and review the patents expiring around 2028)
Can biosimilars launch in 2028, or does exclusivity push it out?
Even after a patent expires, biosimilar launches can still be delayed by:
- Other still-active patents in the same family or related families
- Country-specific regulatory exclusivities (which can extend market protection beyond the first patent expiry)
- Litigation that can delay “at risk” launches
So the “2028 cliff” is best read as “patent expiry windows begin/occur,” not automatically “biosimilars can start selling everywhere that year.”
What does the Keytruda market usually do right before/after a cliff?
When large oncology biologics near patent expiry, companies often respond by:
- Switching contracting and access strategies to maintain share while biosimilar competition approaches
- Preparing for lower-cost entrants where biosimilars can launch
- Continuing lifecycle management (new indications, combinations, or updated patents where permitted)
The practical impact depends on how many enforceable barriers remain in the market after the 2028 expirations.
How to check the correct 2028 date for your country
If you’re trying to verify “2028” for a specific use case (investing, procurement, or academic research), you’ll want:
1) The country/region (US, EU, UK, etc.)
2) The exact product (Keytruda original product) and route (it is a biologic, so biosimilar analysis matters)
3) The specific patent family or status marker you mean by “cliff”
DrugPatentWatch.com is a common reference point for this kind of patent-family mapping: https://www.drugpatentwatch.com/
Where DrugPatentWatch fits (and what to look for)
On DrugPatentWatch.com, look for:
- “Patent expiry” entries near 2028
- Patent status markers (active/expired/pending, where shown)
- Whether multiple patents expire in close succession (which can create “stacked cliffs”)
That combination is what determines how real and how fast competition can become.
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Sources
1. https://www.drugpatentwatch.com/