Sales of Merck’s longtime oncology blockbuster Keytruda will erode more starkly in about 2033 rather than 2029, predicts Bloomberg Intelligence, translating to some $22 billion more in revenue.
As Merck’s oncology juggernaut Keytruda heads toward its curtain call as the highest selling drug, a new analysis from Bloomberg Intelligence suggests that the PD-1 inhibitor could have more exclusivity time than key 2028 patent expirations would suggest. That could mean an additional $22 billion in sales for Merck.
Consensus estimates have generally suggested that Merck will start to see erosion in 2029 as copycat versions of the checkpoint inhibitor enter the market. Sandoz and Bio-Thera are already working on rival products.
But Bloomberg Intelligence (BI) argues that Merck’s global patent portfolio will extend the timeline, with erosion arriving more starkly in about 2033. This could mean sales of about $22 billion for $13 billion in profit from 2030 to 2033, the firm wrote.
“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 brought home $31.7 billion in 2025—49% of Merck’s total revenue. The stakes are high.
Careful Planning
Merck has always based the timeline of Keytruda’s exclusivity future on the December 2028 expiry date for the first patent ever filed, CEO Robert Davis told analysts on the company’s fourth quarter earnings call earlier this month. However, because case law has advanced since the original filing, the company now has more confidence in its ability to defend all of its Keytruda patents.
Nevertheless, Davis said, “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 company’s executives have suggested that the cliff will be more of a hill. BI’s new analysis supports that take, with the firm predicting that Keytruda’s patent cliff may be more of a “gradual earnings slope.”
Keytruda is approved for more than 20 different types of cancer and more than 40 indications with 30 large global patent families protecting it across compositions of matter, formulations and methods of treatment, including dosing regimens. The active ingredient itself, pembrolizumab, is covered, as are certain combinations, formulations and dosing regimens. Some of the relevant patents don’t expire until 2039, BI said.
Merck also received approval in September 2025 for a subcutaneous version called Keytruda Qlex, which has essentially restarted the patent clock with coverage through 2041.
Guggenheim Securities also forecasts that the approval of Keytruda Qlex will help flatten out the cliff. The pharma is benefitting from dosing convenience versus competitors—Bristol Myers Squibb’s Opdivo and Roche’s Tecentriq—and recent changes to drug pricing legislation that will impact the drug.
BI noted that Keytruda will face a Medicare price cut under the Inflation Reduction Act in 2029, which will alter sales outcomes. Depending on the negotiated price, Merck could see closer to $15 billion in sales and $9 billion in profit, rather than $22 billion in sales and $13 billion in profit, BI said.
BMS’ rival drug Opdivo will also face biosimilar competition with sales beginning to erode around the 2029 timeline, BI said. This change in the treatment paradigm could also impact Keytruda, as physicians substitute therapies.
With all this said, BI warned that litigation from pending biosimilar competitors is likely, so timelines could change. But Merck could have more time to shore up its post-Keytruda revenue, via conversions to Keytruda Qlex and by bolstering its pipeline via M&A.
If Keytruda hangs on and brings home that extra $13 billion in profit, Merck will have even more to work with for those future deals, BI noted.
“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.”
