Key Takeaways:
Merck & Co. faces an estimated $24 billion annual revenue gap when Keytruda's U.S. compound patent expires in December 2028, driving a company-wide restructuring and a race to develop the next standard cancer treatment.
"The organizational reshuffle reflects our commitment to sharpening focus as we navigate the lifecycle of our largest asset," Jannie Oosthuizen, newly appointed executive vice president and president of Oncology and MSD International, said in a statement announcing the Feb. 23 restructuring.
Keytruda (pembrolizumab), the world's best-selling drug, generated $31.7 billion in 2025 — nearly half of Merck's total revenue. Without mitigation, the drug faces an estimated 80% revenue erosion post-2028, dropping from its $30 billion peak to roughly $6 billion annually, according to analyst projections. The U.S. Inflation Reduction Act compounds the pressure, with government pricing mechanisms set to begin in January 2028, even before full loss of exclusivity.
The stakes extend beyond Merck's income statement. Keytruda is the backbone of first-line treatment for dozens of cancers, typically paired with chemotherapy. The next standard of care, researchers believe, may pair two innovations — likely bispecific antibodies or novel combination therapies — that could redefine immuno-oncology for the next decade. Merck's response includes a subcutaneous formulation called Keytruda Qlex, which aims to extend exclusivity into 2042 through new method-of-treatment and manufacturing process claims. CEO Rob Davis expects the SC version to capture 30% to 40% of Keytruda's U.S. patient base by 2027, potentially preserving $9 billion to $12 billion per year.
Merck split its Human Health division into two units on Feb. 23: an Oncology Business Unit led by Oosthuizen and a Specialty, Pharma & Infectious Diseases Business Unit led by Brian Foard, formerly of Sanofi. The reorganization is designed to give each division dedicated management as the company diversifies beyond its flagship drug.
The company has deployed more than $19 billion in acquisitions over the past year, including Verona Pharma for its COPD treatment Ohtuvayre and Cidara Therapeutics for the antiviral MK-1406. New product launches include Winrevair for pulmonary hypertension, projected to generate $1.4 billion in 2025, and Enflonsia for RSV, targeting over $1 billion by 2028. Merck also has more than 80 Phase 3 studies underway across oncology, respiratory, and infectious diseases, targeting $70 billion in pipeline opportunities by the mid-2030s.
Not all of Merck's non-oncology portfolio is performing. Gardasil revenue fell 34% year-over-year in the fourth quarter of 2025, driven by collapsing demand in China, raising questions about the breadth of the company's diversification.
Competitors are circling. AstraZeneca's Imfinzi (durvalumab) is positioning as what some analysts call the first real competitive challenge to Keytruda's dominance, beginning in 2028 and beyond. Bristol Myers Squibb and other immuno-oncology players are also advancing next-generation candidates.
Merck shares trade at $123.78, with a price-to-earnings ratio of 16.88 and a dividend yield of 2.6%. Of 36 analysts covering the stock, 24 rate it a Buy, 11 a Hold and one a Sell, with a median price target of $130.
The restructuring and pipeline expansion signal that management expects to offset the Keytruda revenue decline through new product growth and the subcutaneous formulation transition. Investors will watch the next quarterly earnings call for updated segment revenue breakdowns and progress on the SC Keytruda rollout, which will determine whether Merck can transform a $24 billion cliff into a manageable slope.
This article is for informational purposes only and does not constitute investment advice.
