On the second page of Merck's 2025 annual report sits a number that explains almost every strategic move the company is making. Worldwide sales were $65.011 billion. KEYTRUDA and its newer subcutaneous sibling, KEYTRUDA QLEX, contributed $31.680 billion. For every two dollars Merck collected, almost one came from a single cancer-immunotherapy franchise.
This is the kind of problem chief executives are delighted to inherit and obligated to solve. KEYTRUDA changed the treatment of numerous cancers and made Merck a defining company of the immuno-oncology era. It also concentrated the business around a molecule whose exclusivity will not last forever. Merck's next act is therefore neither a reinvention nor a gentle extension. It is a race to turn one exceptional commercial engine into a collection of durable ones.
The working scale of a research company: nearly one quarter of annual sales went back into R&D.
01 / The machineWhat Merck actually does
Merck & Co., known as MSD outside the United States and Canada, develops prescription drugs, biologic therapies, vaccines and animal-health products. That plain description hides an unusually wide operating system. A discovery has to survive laboratory work, clinical trials, regulatory review, manufacturing transfer, reimbursement negotiations and the scrutiny of physicians before it earns a dollar. Most candidates never make the full trip.
The human-health business addresses cancer, infectious disease, cardiovascular and respiratory conditions, diabetes, immunology and other areas. Its best-known products include KEYTRUDA; GARDASIL 9, the HPV vaccine; WINREVAIR for pulmonary arterial hypertension; CAPVAXIVE for pneumococcal disease; and OHTUVAYRE, an inhaled COPD treatment gained through the 2025 purchase of Verona Pharma. In July 2026, the FDA approved LIPFENDRA, Merck's once-daily oral PCSK9 inhibitor for lowering LDL cholesterol in adults with hypercholesterolemia.
Then there is Animal Health, a $6.35 billion business in 2025. It sells pharmaceuticals and vaccines for companion animals and livestock, but also identification, traceability and monitoring technology. The customer can be a veterinarian, a poultry producer, a dairy farmer or someone trying to keep a dog free of fleas and ticks. BRAVECTO alone generated about $1.1 billion in 2025.
One franchise, nearly half the company
02 / The customerThe patient uses it. A system buys it.
Merck says patients come first, but a patient is rarely the direct commercial customer. Human medicines travel through drug wholesalers and retailers, hospitals, government agencies, physicians and managed-care organizations. Vaccines are sold mainly to doctors, distributors, wholesalers and public entities. Pharmacy-benefit managers and insurers influence access. Regulators decide whether a product may be marketed; clinicians decide whether it belongs in care; payers decide how readily people can receive it.
How laboratory work becomes a health product
& license
& prove
& make
& support
Biopharma's relay race: the baton can fall at every handoff.
The problems Merck solves are correspondingly concrete: helping the immune system recognize cancer, preventing infections, lowering damaging cholesterol, treating rare cardiopulmonary disease, protecting livestock and keeping companion animals healthy. But its less visible product is certainty. Large clinical programs, reproducible factories, safety monitoring and global distribution convert a scientific idea into something a health system can trust enough to use at scale.
Revenue usually appears when control of a finished product passes to a customer, but the route to that transaction is expensive and slow. Merck funds discovery internally, licenses outside programs and buys companies with promising assets. If the science works, patents and regulatory exclusivity provide a limited period in which to recover those costs. When protection ends, generic or biosimilar competition can compress sales quickly. The business model is therefore a deliberate mismatch of time: years of spending arrive before approval, while much of the return must be earned before exclusivity fades.
“We try never to forget that medicine is for the people. It is not for the profits.”George W. Merck, 1950
That sentence remains printed in Merck's account of itself because it captures the compact at the center of pharmaceuticals. A company needs profits to fund years of uncertain research, yet its legitimacy depends on improving health and widening access. Pricing, patents and public purchasing make that compact perpetually uncomfortable. Merck's patient-assistance programs and long-running product donations sit on one side of it; the economics of temporary exclusivity sit on the other.
03 / The edgeA portfolio built with other people's brilliance
Merck's competitive advantage is not that all good ideas originate in Rahway. The company is explicit that external science is part of its research model. It has the balance sheet, clinical-development organization, regulatory experience and global sales infrastructure to place large bets on discoveries made elsewhere, then combine them with its own products and expertise.
The partnership roster reads like a map of modern oncology. Daiichi Sankyo contributes antibody-drug conjugate technology; Merck contributes development and commercialization muscle. Moderna and Merck are testing an individualized neoantigen therapy designed from the mutations in each patient's tumor alongside KEYTRUDA. Collaborations with AstraZeneca and Eisai created alliance revenue from LYNPARZA and LENVIMA. Kelun-Biotech's anti-TROP2 antibody-drug conjugate has moved into a broad Phase 3 program. Gilead and Merck are developing a once-weekly oral HIV regimen.
Acquisitions perform the same portfolio function at a different level of commitment. Verona brought OHTUVAYRE and a foothold in COPD. Cidara brought a long-acting antiviral candidate for influenza prevention. Terns, acquired for $6.8 billion in 2026, brought an investigational treatment for chronic myeloid leukemia. None is guaranteed to become another KEYTRUDA. Together, they make clear where management wants new weight: oncology beyond PD-1, cardiopulmonary medicine, infectious disease and immunology.
The late-stage bench · updated April 30, 2026
This model differentiates Merck from a small biotech, which may own a brilliant asset but lack the apparatus to run dozens of global studies. Against Roche, AstraZeneca, Bristol Myers Squibb, Pfizer, Lilly and other large rivals, the difference is narrower. There, competition turns on trial design, clinical evidence, manufacturing, convenience, pricing and the speed with which a drug moves into earlier stages of disease or useful combinations.
Merck sits among the world's large research-led biopharma companies. Its signature strength is oncology, reinforced by vaccines and a meaningful animal-health operation. Its chief strategic vulnerability is the same asset that created that strength: extraordinary dependence on KEYTRUDA.
04 / The clockThe next portfolio is arriving in public
Second-quarter 2026 results offered an early outline. Sales rose 5 percent to $16.6 billion. KEYTRUDA and QLEX reached $8.4 billion, while WINREVAIR climbed 75 percent to $588 million. Animal Health rose 8 percent to $1.8 billion. OHTUVAYRE contributed $204 million. LIPFENDRA's approval gave Merck a cardiovascular product with a familiar form - a daily pill - in a category recently associated with injections.
The numbers are promising without resolving the concentration. KEYTRUDA still supplied just over half of quarterly revenue. New formulations such as QLEX can offer patients and infusion centers a more convenient option, and new combinations can extend clinical utility. They do not erase the patent clock. Merck needs several launches to compound at once, and it needs experimental assets to produce evidence strong enough for regulators, doctors and payers.
There is historical reason to take the attempt seriously. Merck introduced the first commercial statin, developed the first recombinant vaccine approved for human use, built M-M-R vaccination under Maurice Hilleman's leadership and launched a river-blindness donation program whose promise was “as much as needed, for as long as needed.” It also published the first Merck Manual in 1899, when the recommended remedies included bloodletting for acute bronchitis and almond bread for diabetes. Few corporate artifacts demonstrate scientific progress with such accidental comedy.
The company today is both older and less settled than its founding date suggests. Its 75,000 employees include roughly 24,700 people in research. Its pipeline spans oncology, vaccines, cardiovascular and metabolic disease, infectious disease, neuroscience, immunology, ophthalmology and respiratory medicine. Its culture emphasizes patients, respect, ethics and scientific excellence, supported by employee resource groups with about 25,000 members. Yet culture in pharmaceuticals is ultimately tested by decisions: which uncertain program to fund, which negative result to accept and which medicine to make accessible.
Merck's moat is not one molecule. It is the institutional machinery that can find, test, make and distribute the next one.
Where does Merck fit in the market? It is a research-led incumbent operating at global scale, strongest where biology is hard, trials are expensive and commercial execution crosses borders. It is not a hospital, insurer or pharmacy, though all three shape its results. It is not merely an oncology company, though oncology dominates its income statement. And it is not a startup, though each pipeline program begins with startup-like uncertainty.
The most useful way to read Merck is as a portfolio of clocks. Clinical clocks count toward data. Regulatory clocks count toward decisions. Patent clocks count toward competition. Manufacturing clocks count toward supply. The company cannot stop any of them. It can only make sure that enough new clocks begin before the most profitable one runs down.