Merck (MRK)
Develops oncology medicines, vaccines, cardiopulmonary therapies, and animal-health products worldwide.
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Merck is mostly a human-medicine company, with animal health as a smaller but sturdy second business. One cancer drug carries an extraordinary share of the company and funds the search for successors even as cheaper copies draw closer. The transition rests on moving that blockbuster to an easier injection and turning newer lung, vaccine and cancer programs into real sales.
Item facts: FY2025 · year ended Dec 31, 2025, from filings, earnings calls and company pages.
Judgment weights, not filed revenue
The band summarizes business focus and direction. ~ marks estimates.
7 in detail · 16 more below
KEYTRUDA / KEYTRUDA QLEX
Merck's central cancer medicine produced $31.68 billion in FY2025. The watchpoint is whether the under-the-skin QLEX version can soften the blow when lower-cost copies of the original may arrive from late 2028.
Competes with OPDIVO / OPDIVO QVANTIG (Bristol Myers Squibb) · TECENTRIQ (Roche)
In plain English
Cancer can hide from the body's defenses. KEYTRUDA helps the immune system spot and attack it, and doctors use it across many kinds of tumors. Think of one master key that has gradually been cut to open more and more locks.
Hospitals and cancer centers buy the medicine for patients whose treatment qualifies. The original goes through a vein; QLEX is a newer version injected under the skin, which is quicker to give. Merck earns on each dose, but the business depends heavily on legal protection, reliable supply and insurers agreeing to pay.
LYNPARZA
AstraZeneca sells this cancer pill and passes Merck a share of the profit; Merck's cut was $1.45 billion in FY2025. Its main U.S. legal protection ends in 2027.
Competes with ZEJULA (GSK) · Generic olaparib (Natco, Sandoz, Cipla and Zydus)
In plain English
AstraZeneca makes and sells Lynparza, a pill that blocks cancer cells from repairing their damaged genetic instructions. Merck does not ring up the full sale. It owns part of the economics through a partnership.
It works like a shop run by one partner with part of the profit sent next door: AstraZeneca handles the customer-facing business, then shares the result with Merck. Cancer centers, patients and insurers create the underlying demand. The stream lasts only as strongly as approved uses, the partnership terms and protection from generic copies allow.
Sacituzumab Tirumotecan (sac-TMT)
A guided cancer medicine being tested across many tumors, with encouraging late-stage results in endometrial cancer. It is a serious possible successor to today's blockbusters, but approval and manufacturing must come before any sales.
Competes with TRODELVY (Gilead) · DATROWAY (AstraZeneca / Daiichi Sankyo)
In plain English
Picture a guided parcel: one part finds a marker on a cancer cell, then delivers a cell-killing drug directly to it. That is sac-TMT, developed with Kelun-Biotech, a Chinese biotechnology company.
For now, nobody buys it; Merck is paying to prove that it works and can be made safely at scale. Blackstone, a private investment firm, is funding some of the 2026 research in return for possible future payments. If late-stage tests and regulators agree, hospitals and insurers could eventually become customers. Until then, this is a costly option on future cancer sales, not a business line producing cash.
GARDASIL / GARDASIL 9
This vaccine family brought in $5.23 billion in FY2025, even after China shipments were suspended. Limited shipments have resumed, but China's inventory and vaccination demand still make the recovery uncertain.
Competes with CERVARIX (GSK) · CECOLIN (Xiamen Innovax)
In plain English
This is a vaccine against human papillomavirus, or HPV, a common virus that can later cause cervical and other cancers. The idea is simple: protect people before they encounter the virus.
Governments, clinics and private buyers pay for doses, often through large vaccination programs. Demand follows who is eligible, whether families participate and when buyers restock. China made that rhythm especially visible: Merck paused shipments there, then restarted limited deliveries. Zhifei, its Chinese vaccine distributor, receives those shipments, so sales depend on China's inventory cycle as much as on the number of people needing protection.
PROQUAD, M-M-R II and VARIVAX
A scheduled childhood-vaccine family that generated $2.45 billion in FY2025. New birth groups and catch-up shots renew demand, while public policy and the difficult production of live-virus vaccines can move sales around.
Competes with PRIORIX (GSK) · VARILRIX (GSK)
In plain English
Three familiar childhood protections sit here: measles-mumps-rubella, chickenpox, and a combined shot covering all four diseases. They are less like a one-time gadget launch than a school timetable that starts over with each new group of children.
Public health programs, clinics and families pay for doses that follow recommended schedules; older children who missed a shot add catch-up demand. Governments and wholesalers help move the vaccines to clinicians. The money is recurring, but not perfectly smooth: birth numbers, vaccination policy, participation and the challenge of making live-virus vaccines decide how many doses ship in any quarter.
WINREVAIR
An injectable medicine added to existing care for dangerous pressure in the lung's blood vessels. Sales grew 75% in FY2026 Q2; the watch is how quickly specialist centers start and keep patients on it.
Competes with TYVASO DPI / nebulized (United Therapeutics) · OPSUMIT / OPSYNVI and UPTRAVI (Johnson & Johnson)
In plain English
The heart has to work much harder when pressure rises in the blood vessels leading to the lungs. WINREVAIR is an injection that helps rebalance signals behind that pressure, added on top of medicines patients already take.
Specialist centers prescribe it, and pharmacies that handle complex medicines coordinate delivery and monitoring. Merck is paid as patients begin and stay on treatment, although Bristol Myers Squibb receives twenty-two cents from every dollar of sales under an older agreement. Growth therefore depends on finding eligible patients, securing insurer payment, managing safety and keeping supply available.
Animal Health
Veterinary medicines, vaccines and health tools produced $6.35 billion in FY2025. Livestock is the larger side, while pet care adds a steadier second source; disease, farm economics and manufacturing shape both.
Competes with SIMPARICA franchise (Zoetis) · CREDELIO QUATTRO / Farm Animal portfolio (Elanco)
In plain English
The unglamorous counterweight to Merck's human medicines. This business helps veterinarians treat pets and helps farmers prevent and treat disease in livestock, using medicines, vaccines and tools that track animal health.
Veterinarians and producers create the demand; veterinary distributors carry products into clinics and farms. It resembles one supply cabinet serving two very different rooms: a pet clinic on one side, a barn on the other. Pet spending follows treatment and adoption, while livestock demand follows herd health, food production and farm budgets. Merck gets paid product by product, with BRAVECTO its largest named brand here.
KEYTRUDA / KEYTRUDA QLEXMerck's central cancer medicine produced $31.68 billion in FY2025. The watchpoint is whether the under-the-skin QLEX version can soften the blow when lower-cost copies of the original may arrive from late 2028.Merck's central cancer medicine produced $31.68 billion in FY2025. The watchpoint is whether the under-the-skin QLEX version can soften the blow when lower-cost copies of the original may arrive from late 2028.
In plain English
Cancer can hide from the body's defenses. KEYTRUDA helps the immune system spot and attack it, and doctors use it across many kinds of tumors. Think of one master key that has gradually been cut to open more and more locks.
Hospitals and cancer centers buy the medicine for patients whose treatment qualifies. The original goes through a vein; QLEX is a newer version injected under the skin, which is quicker to give. Merck earns on each dose, but the business depends heavily on legal protection, reliable supply and insurers agreeing to pay.
Competes with OPDIVO / OPDIVO QVANTIG (Bristol Myers Squibb) · TECENTRIQ (Roche)
LYNPARZAAstraZeneca sells this cancer pill and passes Merck a share of the profit; Merck's cut was $1.45 billion in FY2025. Its main U.S. legal protection ends in 2027.AstraZeneca sells this cancer pill and passes Merck a share of the profit; Merck's cut was $1.45 billion in FY2025. Its main U.S. legal protection ends in 2027.
In plain English
AstraZeneca makes and sells Lynparza, a pill that blocks cancer cells from repairing their damaged genetic instructions. Merck does not ring up the full sale. It owns part of the economics through a partnership.
It works like a shop run by one partner with part of the profit sent next door: AstraZeneca handles the customer-facing business, then shares the result with Merck. Cancer centers, patients and insurers create the underlying demand. The stream lasts only as strongly as approved uses, the partnership terms and protection from generic copies allow.
Competes with ZEJULA (GSK) · Generic olaparib (Natco, Sandoz, Cipla and Zydus)
Sacituzumab Tirumotecan (sac-TMT)A guided cancer medicine being tested across many tumors, with encouraging late-stage results in endometrial cancer. It is a serious possible successor to today's blockbusters, but approval and manufacturing must come before any sales.A guided cancer medicine being tested across many tumors, with encouraging late-stage results in endometrial cancer. It is a serious possible successor to today's blockbusters, but approval and manufacturing must come before any sales.
In plain English
Picture a guided parcel: one part finds a marker on a cancer cell, then delivers a cell-killing drug directly to it. That is sac-TMT, developed with Kelun-Biotech, a Chinese biotechnology company.
For now, nobody buys it; Merck is paying to prove that it works and can be made safely at scale. Blackstone, a private investment firm, is funding some of the 2026 research in return for possible future payments. If late-stage tests and regulators agree, hospitals and insurers could eventually become customers. Until then, this is a costly option on future cancer sales, not a business line producing cash.
Competes with TRODELVY (Gilead) · DATROWAY (AstraZeneca / Daiichi Sankyo)
GARDASIL / GARDASIL 9This vaccine family brought in $5.23 billion in FY2025, even after China shipments were suspended. Limited shipments have resumed, but China's inventory and vaccination demand still make the recovery uncertain.This vaccine family brought in $5.23 billion in FY2025, even after China shipments were suspended. Limited shipments have resumed, but China's inventory and vaccination demand still make the recovery uncertain.
In plain English
This is a vaccine against human papillomavirus, or HPV, a common virus that can later cause cervical and other cancers. The idea is simple: protect people before they encounter the virus.
Governments, clinics and private buyers pay for doses, often through large vaccination programs. Demand follows who is eligible, whether families participate and when buyers restock. China made that rhythm especially visible: Merck paused shipments there, then restarted limited deliveries. Zhifei, its Chinese vaccine distributor, receives those shipments, so sales depend on China's inventory cycle as much as on the number of people needing protection.
Competes with CERVARIX (GSK) · CECOLIN (Xiamen Innovax)
PROQUAD, M-M-R II and VARIVAXA scheduled childhood-vaccine family that generated $2.45 billion in FY2025. New birth groups and catch-up shots renew demand, while public policy and the difficult production of live-virus vaccines can move sales around.A scheduled childhood-vaccine family that generated $2.45 billion in FY2025. New birth groups and catch-up shots renew demand, while public policy and the difficult production of live-virus vaccines can move sales around.
In plain English
Three familiar childhood protections sit here: measles-mumps-rubella, chickenpox, and a combined shot covering all four diseases. They are less like a one-time gadget launch than a school timetable that starts over with each new group of children.
Public health programs, clinics and families pay for doses that follow recommended schedules; older children who missed a shot add catch-up demand. Governments and wholesalers help move the vaccines to clinicians. The money is recurring, but not perfectly smooth: birth numbers, vaccination policy, participation and the challenge of making live-virus vaccines decide how many doses ship in any quarter.
Competes with PRIORIX (GSK) · VARILRIX (GSK)
WINREVAIRAn injectable medicine added to existing care for dangerous pressure in the lung's blood vessels. Sales grew 75% in FY2026 Q2; the watch is how quickly specialist centers start and keep patients on it.An injectable medicine added to existing care for dangerous pressure in the lung's blood vessels. Sales grew 75% in FY2026 Q2; the watch is how quickly specialist centers start and keep patients on it.
In plain English
The heart has to work much harder when pressure rises in the blood vessels leading to the lungs. WINREVAIR is an injection that helps rebalance signals behind that pressure, added on top of medicines patients already take.
Specialist centers prescribe it, and pharmacies that handle complex medicines coordinate delivery and monitoring. Merck is paid as patients begin and stay on treatment, although Bristol Myers Squibb receives twenty-two cents from every dollar of sales under an older agreement. Growth therefore depends on finding eligible patients, securing insurer payment, managing safety and keeping supply available.
Competes with TYVASO DPI / nebulized (United Therapeutics) · OPSUMIT / OPSYNVI and UPTRAVI (Johnson & Johnson)
Animal HealthVeterinary medicines, vaccines and health tools produced $6.35 billion in FY2025. Livestock is the larger side, while pet care adds a steadier second source; disease, farm economics and manufacturing shape both.Veterinary medicines, vaccines and health tools produced $6.35 billion in FY2025. Livestock is the larger side, while pet care adds a steadier second source; disease, farm economics and manufacturing shape both.
In plain English
The unglamorous counterweight to Merck's human medicines. This business helps veterinarians treat pets and helps farmers prevent and treat disease in livestock, using medicines, vaccines and tools that track animal health.
Veterinarians and producers create the demand; veterinary distributors carry products into clinics and farms. It resembles one supply cabinet serving two very different rooms: a pet clinic on one side, a barn on the other. Pet spending follows treatment and adoption, while livestock demand follows herd health, food production and farm budgets. Merck gets paid product by product, with BRAVECTO its largest named brand here.
Competes with SIMPARICA franchise (Zoetis) · CREDELIO QUATTRO / Farm Animal portfolio (Elanco)
Named in filings, launches and programs
- WELIREGProduct · RampingA newer cancer medicine with $716 million of FY2025 sales; FY2026 Q2 sales grew 67% from a still-modest base.
- Intismeran autogene (V940)Product · Pre-revenueA personalized cancer treatment partnered with Moderna; its late-stage melanoma study with KEYTRUDA met both main goals in August 2026.
- LENVIMA, PREVYMIS and VAXNEUVANCEProduct lineThree marketed human-medicine lines that together produced $2.86 billion in FY2025.
- CAPVAXIVEProduct · RampingA pneumococcal vaccine for adults and certain younger people, with $759 million of FY2025 sales.
- ROTATEQ and PNEUMOVAX 23Product lineEstablished vaccines that together supplied $839 million of FY2025 sales.
- ENFLONSIAProduct · RampingAn infant preventive medicine against respiratory syncytial virus, with only $3 million of first-half FY2026 sales before its main seasonal shipments.
- Alliance Revenue - Reblozyl, Adempas/Verquvo and KoselugoProduct linePartnered and directly sold medicines producing about $1.74 billion for Merck in FY2025.
- OHTUVAYREProduct · RampingAn inhaled maintenance medicine for chronic lung disease, acquired with Verona and already contributing $204 million in FY2026 Q2.
- LIPFENDRA (enlicitide)Product · RampingA daily pill approved in July 2026 to lower harmful cholesterol; it had no FY2025 sales.
- IDVYNSO and new HIV programsProduct line · RampingApproved and experimental pills meant to rebuild Merck's business in HIV, the virus that causes AIDS, including a weekly treatment partnered with Gilead.
- MK-1406 (formerly CD388)Product · Pre-revenueA Cidara-acquired influenza-prevention medicine in late-stage testing, with no sales yet.
- MK-4208 (formerly TERN-701)Product · Pre-revenueA Terns-acquired medicine in early human testing for chronic myeloid leukemia, a blood cancer.
- TulisokibartProduct · Pre-revenueAn experimental immune-disease medicine with positive late-stage bowel-disease results, though a separate lung study was stopped after failure.
- Mature infectious-disease and sleep brandsProduct lineSeven established brands, including LAGEVRIO and BELSOMRA, together generated $1.93 billion in FY2025.
- Other marketed pharmaceuticals and corporate revenuesProduct lineSmaller products and corporate sales add roughly $3.00 billion, filling out the long tail beyond named brands.
- U.S. pricing and direct-access programCustomer programA three-year arrangement offering discounted government pricing and direct access for selected medicines, without any promised purchase volume.
WELIREGProduct · Ramping
A newer cancer medicine with $716 million of FY2025 sales; FY2026 Q2 sales grew 67% from a still-modest base.
Intismeran autogene (V940)Product · Pre-revenue
A personalized cancer treatment partnered with Moderna; its late-stage melanoma study with KEYTRUDA met both main goals in August 2026.
LENVIMA, PREVYMIS and VAXNEUVANCEProduct line
Three marketed human-medicine lines that together produced $2.86 billion in FY2025.
CAPVAXIVEProduct · Ramping
A pneumococcal vaccine for adults and certain younger people, with $759 million of FY2025 sales.
ROTATEQ and PNEUMOVAX 23Product line
Established vaccines that together supplied $839 million of FY2025 sales.
ENFLONSIAProduct · Ramping
An infant preventive medicine against respiratory syncytial virus, with only $3 million of first-half FY2026 sales before its main seasonal shipments.
Alliance Revenue - Reblozyl, Adempas/Verquvo and KoselugoProduct line
Partnered and directly sold medicines producing about $1.74 billion for Merck in FY2025.
OHTUVAYREProduct · Ramping
An inhaled maintenance medicine for chronic lung disease, acquired with Verona and already contributing $204 million in FY2026 Q2.
LIPFENDRA (enlicitide)Product · Ramping
A daily pill approved in July 2026 to lower harmful cholesterol; it had no FY2025 sales.
IDVYNSO and new HIV programsProduct line · Ramping
Approved and experimental pills meant to rebuild Merck's business in HIV, the virus that causes AIDS, including a weekly treatment partnered with Gilead.
MK-1406 (formerly CD388)Product · Pre-revenue
A Cidara-acquired influenza-prevention medicine in late-stage testing, with no sales yet.
MK-4208 (formerly TERN-701)Product · Pre-revenue
A Terns-acquired medicine in early human testing for chronic myeloid leukemia, a blood cancer.
TulisokibartProduct · Pre-revenue
An experimental immune-disease medicine with positive late-stage bowel-disease results, though a separate lung study was stopped after failure.
Mature infectious-disease and sleep brandsProduct line
Seven established brands, including LAGEVRIO and BELSOMRA, together generated $1.93 billion in FY2025.
Other marketed pharmaceuticals and corporate revenuesProduct line
Smaller products and corporate sales add roughly $3.00 billion, filling out the long tail beyond named brands.
U.S. pricing and direct-access programCustomer program
A three-year arrangement offering discounted government pricing and direct access for selected medicines, without any promised purchase volume.