Merck shares climbed roughly 3% in Friday trading, reflecting renewed risk-on positioning into a major near-term regulatory catalyst: an FDA target action (PDUFA) date of April 28, 2026 for an NDA covering doravirine/islatravir, a once-daily oral two-drug regimen for adults with virologically suppressed HIV-1. The April 28 timeline has been part of Merck’s disclosed regulatory roadmap, and today’s move suggests traders are pulling forward expectations and hedging outcomes ahead of that date. (merck.com)

The doravirine/islatravir filing is a notable read-through on Merck’s ability to refresh growth drivers outside its largest franchise, as the market remains sensitive to longer-dated concentration risk around Keytruda. With the FDA decision less than two weeks away, even incremental shifts in perceived approval odds can have an outsized short-term impact on a large-cap pharma’s stock—especially when broader positioning favors defensive, cash-generative healthcare names. (merck.com)

Beyond the HIV catalyst, Merck has been highlighting continued clinical activity across key areas, including cardio‑pulmonary programs presented around major medical meetings, reinforcing a narrative that pipeline breadth can help offset eventual patent pressures in oncology. That broader “post‑Keytruda” framing has also been reinforced by recent bullish sell-side positioning that argues the market is underestimating Merck’s longer-term growth path. (s2.q4cdn.com)

The next clear swing factor is the FDA’s April 28, 2026 action date for doravirine/islatravir; approval, a complete response, or a delay would likely reset near-term sentiment quickly. Investors will also keep scanning for additional late-stage readouts and regulatory milestones in 2026 that can firm up the company’s revenue bridge as Keytruda exclusivity approaches later in the decade. (merck.com)