Merck Q1 2026 Pipeline Updates and Phase III Milestones Overview

Merck Q1 2026: Recent pipeline and Phase III milestone announcements

Below are the specific, recently announced pipeline progress and Phase III-related milestones Merck highlighted in its Q1 2026 earnings call remarks.

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1) FDA milestones / late-stage regulatory progress (Phase III-linked)

• FDA approval of IDVYNSO for adults with virologically suppressed HIV-1 (Phase III SWITCH program basis): Merck stated that the FDA approved IDVYNSO as a new treatment option for adults with virologically suppressed HIV-1, reflecting Merck’s innovation commitment. ¹
• FDA priority review granted for I-DXd in extensive-stage small cell lung cancer (Phase 2 IDeate-Lung01 and Phase 1/2 IDeate-PanTumor01 basis): Merck said the FDA granted priority review for I-DXd (adult patients with previously treated extensive-stage small cell lung cancer). ¹
  • Merck also specified that the FDA set a PDUFA date of October 10 for this I-DXd filing. ²
• FDA priority review for WELIREG supplemental applications (Phase 3 LITESPARK-022 and Phase 3 LITESPARK-011-related labels; plus PDUFA timing):
  • Merck stated that supplemental applications for WELIREG with KEYTRUDA or KEYTRUDA QLEX (based on LITESPARK-022) were granted priority review, with PDUFA date June 19. ²
  • Merck also stated the FDA set a PDUFA date of October 4 for WELIREG plus Lenvima based on LITESPARK-011. ²

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2) Phase III data / Phase III program updates presented or initiated

• Phase III results presented in multiple areas (management summary): Merck said it “presented important Phase III results across multiple other therapeutic areas” during the quarter. ¹
• Enlicitide (cardiometabolic): additional Phase III data presented at ACC
  • Merck said Phase III CORALreefAddOn presented at the American College of Cardiology Congress demonstrated statistically significant and clinically meaningful greater reductions in LDL-cholesterol at 8 weeks versus other oral add-on lipid-lowering therapies on top of background statin therapy. ³
  • Merck also said CORALreefAddOn showed statistically significant greater reductions across secondary endpoints including apolipoprotein B and non-HDL cholesterol. ³
• WINREVAIR (cardiometabolic/respiratory): Phase II full results presented; Phase III warranting further evaluation
  • Merck reported full results from Phase II CADENCE and said WINREVAIR met the primary endpoint (reduction from baseline in pulmonary vascular resistance vs placebo) and that an exploratory secondary endpoint showed a hazard ratio of 0.18 for time to first clinical worsening event at the 0.3 mg/kg dose. ³
  • Merck concluded these results warrant further evaluation in Phase III. ³
    (This is not a Phase III milestone, but it is explicitly framed as “warrant further evaluation in Phase III.”) ³
• Ophthalmology: initiated pivotal Phase IIb/III studies for MK-8748
  • Merck stated it initiated 2 pivotal Phase IIb/III trials evaluating MK-8748 (a Tie-2 agonist/VEGF inhibitor) for neovascular age-related macular degeneration, and that the MALBEC and TORRONTES studies are the first trials in a broader late-phase program. ⁴
  • Merck said the decision to advance development was based on promising results from the Phase I/IIa RIOJA trial. ⁴

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3) Phase III milestone visibility via “near-term events and milestones” (timing)

• ASCO Annual Meeting (June 1, 2026 evening): pipeline progress outline for oncology
  • Merck said: “please mark your calendars” for its annual investor event at ASCO in Chicago on Monday, June 1 where it would outline progress on its oncology pipeline and strategy. ⁴
• Phase III data readouts expected broadly across therapeutic areas in the coming 18 months (management expectation)
  • Merck stated it expects a “particularly robust period of Phase III data readouts from novel candidates over the next 18 months.” ⁵
    (This is forward-looking but is a stated expectation about Phase III milestone timing.) ⁵

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4) What Merck explicitly cited as “Phase III” (directly in the excerpt)

• Merck referenced Phase III trials/studies in connection with multiple programs, including:
  • ISLEND-1 and ISLEND-2 (HIV regimen program mentioned alongside “Phase III ISLEND-1 and 2 trials”). ⁶
  • Tulisokibart (TL1A inhibitor) with Phase III ATLAS-UC in ulcerative colitis and Phase II ATHENA in SSc-ILD as part of the immunology program update. ⁶
  • MK-3000 Phase III BRUNELLO for diabetic macular edema. ⁶
  • MK-8748 retinal diseases with Phase II portion of RIOJA also referenced in that late-stage pipeline update. ⁶

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Bottom line (Q1 2026 “pipeline progress + Phase III milestones”)

In Q1 2026, Merck’s most concrete pipeline announcements tied to late-stage/Phase III execution were:

1. Completed FDA actions: IDVYNSO approval in HIV-1 and priority review for I-DXd in extensive-stage small cell lung cancer, with explicit PDUFA timing. ¹²
2. Ongoing regulatory progress for Phase III-based label programs: WELIREG supplemental applications received priority review (including PDUFA June 19) and additional PDUFA October 4 timing for another WELIREG combination. ²
3. Phase III clinical readouts discussed: Merck highlighted Phase III CORALreefAddOn results at ACC for enlicitide, and it reported Phase III results across multiple therapeutic areas overall. ¹³
4. Phase IIb/III pivot to pivotal trials in ophthalmology: MK-8748 advanced via initiated pivotal Phase IIb/III trials (not Phase III completion, but late-stage milestone progression). ⁴

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