Merck's Keytruda Drives its 2025 Revenue Surge: What's Ahead?

Merck MRK has a strong foothold in the oncology market, primarily supported by its biggest revenue driver, Keytruda. The blockbuster PD-1 inhibitor accounts for around 55% of the company’s pharmaceutical sales and has played an instrumental role in driving Merck’s steady revenue growth over the past few years.

Keytruda, approved for various cancer indications, recorded sales of almost $31.7 billion in 2025, up 7% year over year. Importantly, the company expects the growth to continue till Keytruda loses patent exclusivity in 2028.

Keytruda’s sales are gaining from rapid uptake across earlier-stage indications. Continued strong momentum in metastatic indications is also boosting sales growth. In 2026, the company expects Keytruda sales to continue to grow. The recent FDA approval of Keytruda and Keytruda Qlex (subcutaneous formulation of Keytruda) for the ovarian cancer indication should contribute to sales growth in 2026, as the drug previously had no approved use in this indication.

Though Keytruda intravenous (IV) is set to face loss of exclusivity in 2028, its sales are expected to stay strong until then. Management expects Keytruda to achieve peak sales of $35 billion by 2028 before it loses exclusivity.

Building on this, Merck has been working on different strategies to drive Keytruda's long-term growth. These include innovative immuno-oncology combinations, including Keytruda with LAG3 and CTLA-4 inhibitors. In partnership with Moderna, Merck is developing a personalized mRNA-based cancer vaccine, intismeran autogene (V940/mRNA-4157), in combination with Keytruda. The regimen is currently being evaluated in pivotal phase III studies for earlier-stage and adjuvant NSCLC as well as adjuvant melanoma.

Merck recently announced that it is reorganizing its Human Health segment into two focused units: an Oncology Business Unit and a Specialty, Pharma & Infectious Diseases Business Unit. The streamlined structure is expected to enhance commercial focus and support sustainable long-term growth, particularly as Merck prepares for revenue diversification ahead of Keytruda’s eventual loss of exclusivity in 2028.

On its fourth-quarter 2025 conference call, Merck said it expects over $70 billion of potential non-risk-adjusted commercial opportunity for the current pipeline by the mid-2030s. Management also noted that this figure ($70 billion) is more than twice the prior peak consensus sales estimate of $35 billion for Keytruda in 2028 and represents a $20 billion increase from what the company had expected just one year ago.

Merck’s latest reorganization into focused units directly supports the company’s projected $70 billion commercial opportunity by the mid-2030s. By creating dedicated leadership for Oncology and for Specialty, Pharma & Infectious Diseases, Merck can more effectively advance and launch its diversified pipeline.

PD-L1 Inhibitors Competing With MRK's Keytruda

Keytruda faces competition from other PD-L1 inhibitors, including Bristol Myers’ BMY Opdivo, Roche’s RHHBY Tecentriq and AstraZeneca’s AZN Imfinzi.

BMY’s Opdivo, like Keytruda, is approved across multiple cancer types, including lung, melanoma and kidney cancers. Bristol Myers recorded $10.05 billion in Opdivo sales in 2025, up 8% year over year.

Tecentriq is Roche’s leading immuno-oncology drug approved for multiple cancer indications. RHHBY recorded CHF 3.56 billion in Tecentriq sales in 2025, up 3% year over year.

AZN’s Imfinzi generated sales of $6.06 billion in 2025, up 28%, driven by demand growth in bladder and liver cancer indications. Imfinzi has strategically expanded its use across multiple cancer indications, strengthening AstraZeneca’s oncology portfolio.

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