November 18, 2025 — Merck & Co. (NYSE: MRK) is trading higher today after the company reported new mid‑stage data for its cardiopulmonary medicine Winrevair (sotatercept‑csrk), fueling optimism about growth beyond Keytruda and adding momentum to last week’s acquisition of Cidara Therapeutics.
What’s moving the stock
Merck announced before the U.S. market open that Winrevair met the primary endpoint in the Phase 2 CADENCE study in adults with combined post‑ and precapillary pulmonary hypertension (CpcPH) due to heart failure with preserved ejection fraction (HFpEF). The trial showed a “statistically significant and clinically meaningful” reduction in pulmonary vascular resistance versus placebo. Merck said the proof‑of‑concept data support advancing Winrevair into Phase 3 and that results will be presented at a future scientific meeting. There are currently no treatments specifically approved for CpcPH. Merck.com
Market reaction: In early U.S. trading on Tuesday, reports showed Merck shares up roughly 3%–4% around the mid‑$90s following the Winrevair update. Barron’s cited a 3.4% move to $95.97, and MarketWatch showed premarket gains of about 3.1% to $95.75 at 8:21 a.m. ET; IBD later noted shares near $96.29 intraday.
Why this matters for Merck’s 2026–2030 story
- Pipeline beyond Keytruda: With Keytruda’s U.S. patent expiry looming in 2028, investors are watching for late‑decade revenue bridges. Barron’s highlighted that analysts have lifted 2030 sales forecasts for Winrevair to >$5.5B (from just over $400M last year), contingent on broader label expansion. Today’s CADENCE win strengthens the case to study the drug in additional patient groups.
- Clinical next steps: Merck intends to proceed to a Phase 3 program in CpcPH due to HFpEF, building on Winrevair’s existing approvals for pulmonary arterial hypertension (PAH).
The Cidara backdrop: A late‑phase flu asset with multibillion potential
Just ahead of today’s data, Merck agreed to acquire Cidara Therapeutics for $221.50 per share in cash (about $9.2B), adding CD388, a long‑acting antiviral intended as a non‑vaccine approach to flu prevention. Merck on Monday said it sees a “> $5B” commercial opportunity from the asset. The company expects the deal to close in the first quarter of 2026, subject to customary approvals. Reuters+1
Today’s Merck headlines (Nov 18, 2025)
- Winrevair hits the mark in CADENCE; Phase 3 planned — Company news release, 6:45 a.m. ET.
- Shares advance on Winrevair optimism, post‑Keytruda narrative — Barron’s daytime update.
- Coverage reiterates upside but notes a long road to approval — IBD midday wrap.
- Trade press reports on the same mid‑stage win — Seeking Alpha and BioSpace.
Don’t mix up the two “Mercks”
There are two different companies named Merck:
- Merck & Co., Inc. (NYSE: MRK) — U.S.‑based (Rahway, N.J.), the focus of today’s Winrevair news and stock move.
- Merck KGaA (XETRA: MRK, also shown as MRK.DE) — Germany‑based; its Frankfurt‑listed shares were trading lower this afternoon in Europe (about −3% around €111–€112), unrelated to the U.S. Winrevair headline.
What to watch next
- Phase 3 design & timelines for Winrevair in CpcPH/HFpEF, plus readouts in related cardiopulmonary settings.
- Regulatory and integration milestones for the Cidara acquisition, and updated market sizing for CD388 in high‑risk flu populations.
- Broader late‑cardio pipeline updates, including recent success for Merck’s oral PCSK9 candidate enlicitide decanoate in Phase 3 programs (context for the company’s growing cardiovascular footprint).
Bottom line
Merck’s stock is higher today as fresh Winrevair data refocus investors on the company’s growing cardio‑pulmonary franchise and its potential to complement (and eventually outlive) Keytruda’s exclusivity. Coupled with the Cidara deal and its large flu‑prevention opportunity, the news flow points to a more diversified late‑decade growth plan. Execution—moving Winrevair into Phase 3, navigating Cidara’s close, and converting late‑stage assets into approvals—remains the key catalyst path into 2026.
Disclaimer: This article is for informational purposes only and is not investment advice. Always do your own research and consider consulting a licensed financial professional.
