Merck’s cancer drug Keytruda may maintain its market dominance for several years beyond initial expectations, according to a new analysis from Bloomberg Intelligence (BI). The report suggests that the PD-1 inhibitor could continue to generate significant revenue for Merck past the anticipated 2028 patent expiration date.
While industry consensus has predicted that Merck would begin facing competition from biosimilar products in 2029, BI’s analysis indicates that the company’s extensive global patent portfolio could delay substantial sales erosion until around 2033. This extension could result in an additional $22 billion in sales and $13 billion in profit between 2030 and 2033.
“Merck’s global patent portfolio protecting its blockbuster cancer drug Keytruda is dense and strategically layered to provide solid protection across jurisdictions, with its structure exactly what we’d expect to see for well thought-out coverage for such a product,” BI wrote.
Keytruda generated $31.7 billion in revenue in 2025, accounting for nearly half of Merck’s total income. CEO Robert Davis stated during the company’s fourth quarter earnings call that Merck continues to plan based on the December 2028 expiry date of Keytruda's first patent filing. He noted advances in case law have increased confidence in defending these patents but added, “for planning purposes we continue to assume 2028 because I think that’s a conservative assumption. We’ll have to see where it goes.”
The BI report describes the expected decline as more gradual than previously forecasted, calling it a “gradual earnings slope” rather than a sharp drop-off. Keytruda is currently approved for over 20 types of cancer and more than 40 indications, protected by about 30 major global patent families covering various aspects including composition, formulations, combinations, and dosing regimens. Some patents are not set to expire until as late as 2039.
In September 2025, Merck gained approval for Keytruda Qlex—a subcutaneous version—which extends certain patent protections through at least 2041. Guggenheim Securities projects this new formulation will help ease the impact of upcoming generic competition due to its convenience compared with other treatments like Bristol Myers Squibb’s Opdivo and Roche’s Tecentriq.
Despite these advantages, BI pointed out that changes under the Inflation Reduction Act will require Medicare price negotiations starting in 2029. This policy shift could reduce expected sales figures; depending on negotiated prices, revenues might reach only $15 billion with profits of $9 billion during this period instead of previous higher estimates.
Competition remains a concern as BMS’ Opdivo is also projected to lose exclusivity around the same time frame, potentially altering treatment practices among physicians and affecting Keytruda's market share further.
BI cautioned that ongoing litigation related to biosimilar competitors may influence these timelines but suggested Merck has opportunities ahead: “Biosimilar competition is coming and Keytruda revenue and profit will fall, yet Merck has more time to grow its revenue base and for a numerically strong, late-stage pipeline to mature, launch and contribute increased sales and profit.”
