Merck Reports Moderna Melanoma Vaccine Cut Recurrence or Death Risk 42%
Merck reported that Moderna's personalized cancer vaccine, intismeran, combined with Keytruda significantly reduced the risk of melanoma recurrence or death by 42% versus Keytruda alone in the Phase 3 INTerpath-001 trial.
Merck (MRK) reported that the personalized cancer vaccine intismeran, developed with Moderna (MRNA), combined with Keytruda significantly reduced the risk of melanoma recurrence or death by 42% versus Keytruda alone in the Phase 3 INTerpath-001 trial, according to the summary supplied. Overall survival data remain immature, but a favorable trend was observed with the combination. No new safety signals emerged, and results were generally consistent with previously reported studies of the combination. The full data are scheduled for presentation at the ESMO Congress in Madrid on Saturday, Oct. 24.
What was reported
| Measure | Result | Source |
|---|---|---|
| Recurrence or death (Phase 3) | 42% risk reduction vs. Keytruda alone | Summary supplied |
| Overall survival (Phase 3) | Immature; favorable trend with the combination | Summary supplied |
| Safety (Phase 3) | No new safety signals; consistent with prior studies | Summary supplied; Merck and Moderna, Aug. 19 |
| Recurrence-free survival (Phase 2b) | 49% risk reduction (hazard ratio 0.51) | Merck and Moderna, Aug. 19 |
| Distant metastasis-free survival (Phase 2b) | 59% risk reduction (hazard ratio 0.411) | Merck and Moderna, Aug. 19 |
The 42% reduction is smaller than the 49% recurrence-free survival benefit from the earlier Phase 2b KEYNOTE-942 trial. In August, Merck and Moderna said INTerpath-001 met its primary endpoint of recurrence-free survival and its key secondary endpoint of distant metastasis-free survival at a pre-specified interim analysis, without releasing numbers. Overall survival is still being evaluated.
About the trial
INTerpath-001 is a randomized, double-blind Phase 3 trial of 1,137 patients with completely resected high-risk (stage IIB to IV) cutaneous melanoma. Patients were randomized 2:1 to intismeran, dosed at 1 mg every three weeks for up to nine doses, plus Keytruda, or to Keytruda alone. Each intismeran therapy is built from an individual patient's tumor and codes for up to 34 neoantigens. Merck estimates about 112,000 new U.S. melanoma cases and more than 8,500 deaths in 2026.
Market context
Moderna shares fell about 25% on Thursday after detailed results apparently leaked online before the scheduled presentation, and Merck shares were down about 1%. Investors have questioned whether the benefit over existing immunotherapy justifies the potential cost, particularly after Moderna's rally this year.
What comes next
Georgina Long is scheduled to present the Phase 3 data on Saturday, Oct. 24, at 10:30 a.m. ET, and Moderna will host an investor webcast at 1:00 p.m. ET that day on its investor relations site. Merck has scheduled an oncology investor event for Monday, Oct. 26, at 2:30 p.m. ET. The companies said in August that they plan to discuss filings with regulators.
Sources: Merck and Moderna Phase 3 INTerpath-001 announcement (Aug. 19), Merck's ESMO 2026 announcement (Oct. 13) and Moderna's ESMO 2026 announcement (Sept. 21). Phase 3 efficacy, survival and safety details are as given in the summary supplied. This is informational, not a recommendation to buy or sell.
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