MRK Stock Soars As Keytruda Delivers Again In Q1, Winrevair Accelerates — CEO Signals Robust Phase 3 Readout Period Ahead

• Merck’s widely used immunotherapy, Keytruda, drove the company’s topline growth during the quarter, accounting for nearly half of Merck’s total sales during this period.
• Keytruda sales during Q1 stood at $8.03 billion, growing by 12% year-on-year, with Merck stating that the growth was primarily driven by higher global demand in metastatic indications.
• Merck reported 88% YoY growth in Winrevair sales, driven by strong U.S. uptake and early launches in Japan and the European Union.

Shares of Merck & Co. Inc. (MRK) gained in Thursday’s pre-market session after the company posted better-than-expected first-quarter (Q1) results, powered by the strength of Keytruda and Winrevair.

Merck reported an adjusted loss of $1.28 per share on revenue of $16.3 billion in Q1, compared to Wall Street estimates of a loss of $1.47 on revenue of $15.85 billion, according to Fiscal.ai data.

Merck shares were up more than 3% in Thursday’s pre-market trade.

Keytruda, Winrevair Drive Sales Growth

Merck’s widely used immunotherapy, Keytruda, drove the company’s topline growth during the quarter, accounting for nearly half of Merck’s total sales during this period.

Keytruda sales during Q1 stood at $8.03 billion, growing by 12% year-on-year. The company stated that the growth was primarily driven by higher global demand in metastatic indications including urothelial cancer, as well as strong global uptake in earlier-stage indications, including triple-negative breast cancer, cervical cancer and renal cell carcinoma (RCC).

Overall, Merck’s pharmaceutical sales stood at $14.35 billion in Q1, growing in line with its total sales. The company stated that pharma sales were largely fueled by oncology as well as gains in cardiometabolic and respiratory segments.

Merck also reported 88% year-on-year growth in sales of Winrevair, its treatment for adults with Pulmonary Arterial Hypertension (PAH). The company stated that the growth of Winrevair primarily reflects a continued uptake in the U.S. and early launch uptake in markets like Japan and the European Union.

Merck CEO Touts Robust Phase 3 Readout Period Ahead

Merck CEO Robert M. Davis touted a robust Phase 3 data readout period ahead for the company.

“I am pleased with our progress and excited for what’s ahead, as we enter a particularly robust period of Phase 3 data readouts and deliver on the promise of our pipeline for patients,” he said.

Davis added that the company strengthened its pipeline during Q1, which includes the planned acquisition of Terns Pharmaceuticals Inc. (TERN) for an equity value of $6.7 billion.

He also highlighted the approval of Idvynso by the U.S. Food and Drug Administration (FDA) for treating HIV-1 in virologically suppressed adults.

Merck stated that the Phase 2 CADENCE results delivered clear proof of concept for Winrevair in adults with combined post- and precapillary pulmonary hypertension, supporting advancement into a registrational Phase 3 trial for this patient group.

Cidara Therapeutics Acquisition Hits Bottomline

Merck also stated that the $9.2 billion acquisition of Cidara Therapeutics resulted in a $3.62 per-share charge, as the company swung to a loss during the quarter after reporting adjusted earnings per share (EPS) of $2.22 in the same period a year ago.

The company raised its adjusted EPS forecast for full-year 2026 to a range of $5.04 to $5.16, up from its previous outlook of $5 to $5.15.

Merck also narrowed its 2026 revenue guidance to a range of $65.8 billion to $67 billion, compared to its previous outlook of $65.5 billion to $67 billion.

How Did Retail Traders React?

Retail sentiment on Stocktwits around Merck trended in the ‘neutral’ territory, with message volumes at ‘normal’ levels at the time of writing.

One user thinks that Merck’s current share price is probably its top now.

MRK stock is up 5% year-to-date and 31% over the past 12 months. The S&P 500 ETF (SPY) and the iShares Core S&P 500 ETF (IVV) are up 28% over the past 12 months.

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