Merck is building a bridge over its patent cliffs
- KEYTRUDA QLEX is defending the core oncology franchise, generating $463 million following permanent J-code establishment.
- WINREVAIR sales hit $588 million in Q2 2026, marking it as a clear cardiovascular growth driver.
- The FDA approved LIPFENDRA, an oral PCSK9 inhibitor that adds a massive new primary care asset to the portfolio.
- GARDASIL stabilized with 3 percent global growth to $1.2 billion, easing fears of a complete collapse after earlier China weakness.
- JANUVIA and BRIDION still lose U.S. exclusivity in mid-2026, but the BRIDION decline is expected to be slower than previously modeled.
A portfolio transition gaining traction
Merck is a portfolio in transition, but the bridge to its future is getting stronger. KEYTRUDA remains the core profit engine, while WINREVAIR is proving to be a massive cardiovascular growth driver with $588 million in Q2 2026 sales. The recent FDA approval of LIPFENDRA adds another major asset to this secondary pillar.
The challenge remains timing. JANUVIA and JANUMET lost U.S. market exclusivity in May 2026, and BRIDION follows in July 2026. Loss of exclusivity means cheaper generic drugs enter the market, usually causing sales to fall quickly.
The bull case is strengthening because Merck is successfully defending its core with KEYTRUDA QLEX and building new revenue streams fast enough to offset older product losses. Management also expects the BRIDION decline to be slower than initially feared due to limited generic competition.
The bear case centers on whether primary care doctors will adopt LIPFENDRA quickly enough and if pipeline assets will succeed. If new launches plateau or face access hurdles, the eventual KEYTRUDA patent cliff later this decade will still leave a large revenue gap.
Science, sales, and reinvestment
Merck discovers, develops, makes, and sells medicines and vaccines. Most sales come from human health products sold to drug wholesalers, retailers, hospitals, governments, and health plans. A smaller but growing Animal Health business sells medicines, vaccines, and monitoring tools for livestock and pets.
The model works best when Merck owns protected drugs with strong demand. Patents and regulatory exclusivity help protect pricing and market share for a time. When that protection ends, generic or competing products can take a large share quickly.
Merck is actively preparing for that cycle. Its 2025 Restructuring Program is meant to generate about $3.0 billion in annual savings by the end of 2027. The company is reinvesting these savings into growth areas, late-stage pipeline work, and new launches like WINREVAIR and LIPFENDRA.
That plan adds discipline, but it also shows the pressure. Merck must keep funding expensive research while replacing revenue from older products and handling pricing pressure from U.S. government programs.
The drugs that matter most
KEYTRUDA
KEYTRUDA is Merck's lead cancer drug and the main profit engine. Management has framed the drug as central to growth through its peak years.
Keytruda Qlex
Keytruda Qlex is the subcutaneous version of KEYTRUDA, given by injection under the skin. It generated $463 million in Q2 2026 and helps defend the franchise.
WINREVAIR
WINREVAIR treats pulmonary arterial hypertension. Sales reached $588 million in Q2 2026, making it the clearest new launch success so far.
LIPFENDRA
LIPFENDRA is a newly approved oral PCSK9 inhibitor to help reduce LDL cholesterol. It serves as a massive new primary care asset for the cardiometabolic division.
GARDASIL and GARDASIL 9
GARDASIL is Merck's HPV vaccine franchise. It stabilized in Q2 2026 with 3 percent global growth after suffering sharp demand drops in China.
JANUVIA and JANUMET
JANUVIA and JANUMET are diabetes products now facing generic competition. They lost U.S. market exclusivity in May 2026.
BRIDION
BRIDION is used to reverse certain anesthesia effects after surgery. It loses U.S. market exclusivity in July 2026, though management expects a slower decline than previously modeled.
Animal Health
Animal Health sells veterinary medicines, vaccines, and health management tools. It continues to deliver solid sales growth across livestock and companion animal portfolios.
Mostly human health
Mix is based on recent reportable segment sales. The human health division drives the vast majority of revenue, heavily weighted toward oncology and cardiometabolic drugs.
What could break the story
LIPFENDRA adoption stalls
High impact · Medium oddsThe bull case requires LIPFENDRA to scale into a massive growth driver. If primary care physician inertia and access hurdles limit its uptake against entrenched generic statins and injectable PCSK9s, Merck will lose a key growth pillar.
Mid-2026 generic shock
High impact · High oddsJANUVIA and JANUMET lose U.S. exclusivity in May 2026, and BRIDION follows in July 2026. While the BRIDION decline might be slower than expected, the first full quarter after generic entry will show exactly how steep the revenue hit really is.
WINREVAIR growth slows too soon
High impact · Medium oddsWINREVAIR is a strong new launch proof point, but investors still do not know its steady run rate. If the drug plateaus near current levels, it may not offset the losses from older franchises.
Pricing pressure expands
Medium impact · High oddsThe Inflation Reduction Act has subjected Januvia, Janumet, and LENVIMA to government price setting. Merck also expects KEYTRUDA to face selection in the future. Lower prices can reduce sales and margins even when prescription demand stays healthy.
Pipeline spending fails to pay off
High impact · Medium oddsMerck is spending heavily to acquire and build future products, like the Terns CML asset and its broad ADC pipeline. If late-stage data disappoints, the company may spend a lot without filling the late-decade revenue gap.
