Merck and Moderna's personalised mRNA melanoma vaccine succeeds in Phase 3 trial
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Merck and Moderna announced on 19 August 2026 that their personalised mRNA melanoma vaccine, intismeran autogene, met its primary endpoint in the Phase 3 INTerpath-001 trial. The trial enrolled 1,137 patients with resected stage IIB-IV cutaneous melanoma. The companies have not yet disclosed the magnitude of benefit.
Key Facts
- The Phase 3 INTerpath-001 trial enrolled 1,137 patients with completely resected stage IIB-IV cutaneous melanoma.
- The trial met its primary endpoint of recurrence-free survival and a key secondary endpoint of distant metastasis-free survival.
- Patients were randomised 2:1 to receive intismeran autogene plus pembrolizumab or pembrolizumab alone.
- Treatment duration was approximately 56 weeks, with up to nine vaccine doses every three weeks.
- Hazard ratios, confidence intervals, and recurrence rate differences have not been published and will be presented at an upcoming medical meeting.
Trial Design
INTerpath-001 enrolled 1,137 patients with completely resected stage IIB-IV cutaneous melanoma who had not previously received systemic treatment. Patients were randomised two to one to receive intismeran autogene alongside pembrolizumab (Keytruda) or pembrolizumab alone. Treatment ran for approximately 56 weeks, with up to nine doses of the vaccine every three weeks and pembrolizumab every six weeks. The trial identifier on ClinicalTrials.gov is NCT05933577.
Efficacy Results
The trial met its primary endpoint, recurrence-free survival, meaning patients on the combination were significantly less likely to have their melanoma return within the study's follow-up window. It also met a key secondary endpoint, distant metastasis-free survival, tracking whether the cancer spread to distant organs. A third measure, overall survival, is still being followed.
Data Disclosure
Merck and Moderna have not published the hazard ratios, confidence intervals, or the actual difference in recurrence rates between the two groups. That level of detail is being held for presentation at an upcoming international medical meeting, with regulatory filings to follow. Companies routinely announce that a trial met its endpoints ahead of peer-reviewed data due to conference reporting agreements and preparation time.
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Merck and Moderna's personalised mRNA melanoma vaccine succeeds in Phase 3 trial
