Could You Have Seen Merck Stock’s Pipeline Run Coming

Merck (MRK) stock gained about 89% in the year from mid-September 2025, against a 17.1% price gain for the S&P 500. It also beat Johnson & Johnson (JNJ), up 58%, and Eli Lilly (LLY), up 54%. The signs were public long before the run, in what management kept saying about its drug pipeline. The reported sales told a different story.

What Was Merck Promising Before Its Sales Fell?

In February 2025, management said Merck had 20 possible new growth drivers, almost all with blockbuster potential. It put the revenue opportunity from those programs at over $50 billion. Three late-stage readouts for enlicitide, an oral cholesterol drug, were due in 2025.

Then the reported numbers got worse. Revenue for the second quarter of 2025 fell 2%, to $15.8 billion. That drop masked solid gains across the rest of the business, which were wiped out by a single product in a single market: GARDASIL sales in China plunged by about $1.3 billion in that quarter. Merck said it would not resume GARDASIL shipments to China until at least the end of 2025.

In the July 2025 update that reported those numbers, the CEO said investors underappreciated the pipeline. The first proof point on the list was WINREVAIR, a treatment for pulmonary arterial hypertension whose cumulative sales passed $1 billion within 15 months of launch. You had to choose between the promise and the weak quarter.

When Did Merck's Proof Start Arriving?

The pivotal enlicitide result landed shortly before the run began. On September 2, 2025, Merck said enlicitide met all its primary and key secondary goals in a pivotal cholesterol study called CORALreef Lipids. Enlicitide is the first oral PCSK9 inhibitor to cut LDL cholesterol meaningfully in Phase 3. The first two enlicitide studies had already come back positive by July 2025.

The rest arrived during the run. By August 4, 2026, the FDA had approved LIPFENDRA, the pill tested in CORALreef Lipids and the first approved pill of its kind. The CEO said two cancer drugs, sac-TMT and I-DXd, had positive readouts that Merck had not expected until 2027.

Sales growth stayed modest.Revenue for the second quarter of 2026 rose 5%, or 4% without currency effects, to $16.6 billion. What changed was how much of the pipeline had been proven, and the CEO said that was happening faster than Merck expected.

Could You Have Bought Merck's Pipeline Before It Was Proven?

Partly. The thread was public from February 2025, and the enlicitide result gave you a dated sign before the run started. But even after the run began, the shares dipped to a low of $75.39, below the roughly $79 starting point, so holding took patience. Buying in mid-2025 meant trusting a management forecast while reported sales were falling.

So the signs were real, but until September 2025 most of them were still promises. Next time, watch for a named trial readout that lands while reported sales still look weak. After a run like this one, our market-implied growth screen shows how much growth a stock price already assumes.

Catching The Surge Matters Less Than Keeping It

Catching a move early is a real edge; keeping the gains it produces takes a different discipline. Concentration tends to arrive by accident rather than by decision. What your largest position would do to your net worth is exactly what the Trefis Wealth team computes, with the same rules-based systematic discipline that runs our High Quality Portfolio. Request a free vulnerability audit of your biggest positions.