Intismeran Adjuvant Melanoma Trial Cuts Recurrence Risk by 42%
October 23, 2026
Intismeran adjuvant melanoma treatment combined with KEYTRUDA cut the risk of recurrence or death by 42% compared with KEYTRUDA alone, according to detailed Phase 3 INTerpath-001 results that Merck and Moderna announced on 22 October 2026.
The randomized, double-blind trial enrolled 1,137 patients with completely resected stage IIB-IV cutaneous melanoma, who were randomized 2:1 to intismeran plus KEYTRUDA or placebo plus KEYTRUDA. At the primary analysis, after a median follow-up of 24.6 months, the hazard ratio for recurrence-free survival was 0.58 (95% CI, 0.45 to 0.75; two-sided p<0.001). Distant metastasis-free survival also improved, with a hazard ratio of 0.62 (95% CI, 0.45 to 0.85).
Intismeran adjuvant melanoma benefit after six months
The benefit was larger after six months on the intismeran immunization regimen. In a pre-specified sensitivity analysis, the hazard ratio for recurrence or death was 0.42 (95% CI, 0.30 to 0.58) against KEYTRUDA alone. In the first six months, the two arms performed comparably, with a hazard ratio of 0.99.
Overall survival data are not yet mature, although the trend favors intismeran plus KEYTRUDA. The safety profile was generally consistent with earlier studies of the combination, and no new safety signals were observed. Merck and Moderna are engaging with regulatory authorities, and the results will be presented at ESMO Congress 2026 and published in The New England Journal of Medicine.
The results build on Phase 2b data for the same combination, including five-year follow-up presented at ASCO 2026.
Why it matters
The headline figure is the primary analysis, but the six-month pattern changes how it should be read. Because the arms were comparable in the first six months, the gain rests on the later part of the regimen. Merck says INTerpath-001 is the first Phase 3 study to show a clinically meaningful improvement in recurrence-free and distant metastasis-free survival over standard-of-care KEYTRUDA in resected melanoma. Its approach, an individualized neoantigen therapy designed from each patient’s tumor, is still investigational, and overall survival will decide how far the benefit extends.
Source: Merck news release, 22 October 2026.
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