Moderna, Merck prepare filings for mRNA melanoma vaccine

The personalized mRNA cancer vaccine from Merck ↘ 0.14% and Moderna ↗ 5.27% cut the risk of recurrence or death by 42% in patients with high-risk melanoma that had been surgically removed. That is the first positive phase 3 result for an mRNA-based cancer therapy, and the companies are now preparing regulatory submissions.freep.com

The companies first announced topline results on August 19, 2026. The INTerpath-001 trial of intismeran autogene plus Keytruda (pembrolizumab) met its primary endpoint, recurrence-free survival, and a key secondary endpoint, distant metastasis-free survival. The fuller data that some recent reports described as still to come have already been released. They were presented at the ESMO Congress 2026 in October.news.modernatx.com+1

What the data show

The trial enrolled 1,137 adults with completely resected stage IIB–IV melanoma. They were randomly assigned to pembrolizumab plus either intismeran (757 patients) or a placebo (380 patients). After a median follow-up of 24.6 months, the hazard ratio for recurrence or death was 0.58. At two years, 82.2% of patients on the combination were alive without recurrence, compared with 70% on pembrolizumab alone. The combination also lowered the risk of distant metastasis or death by 38%, and the two-year rates were 88.5% versus 80.2%.onclive.com+1

The benefit grew after the six-month vaccination course. A pre-specified analysis found a 58% reduction in recurrence or death from that point on. Overall survival data are still immature. The hazard ratio of 0.77 did not reach statistical significance, and grade 3 or higher adverse events occurred in 23.6% of combination patients versus 20.3% in the control group.onclive.com+1

How the vaccine works

Each dose is built from sequencing of the patient's own tumor and encodes up to 34 neoantigens intended to train the immune system to find cancer cells. Lead author Georgina Long of Melanoma Institute Australia said the approach makes a "wanted poster" of the cancer as mRNA. ESMO's James Larkin, who was not involved in the trial, called the results "a major advance" and said the combination is "very well tolerated."medicalxpress.com+1

Mark Stares, who led the trial site in Edinburgh, said the findings show that "cancer vaccines can work" and support research in other cancers. The program now includes nine phase 2 and phase 3 trials in melanoma, lung, bladder and kidney cancers.news.modernatx.com+1

Road to approval

Moderna said on November 6, in its third-quarter report, that the partners are preparing for a potential commercial launch if regulators approve the vaccine. Tech Times reported that the full results were published in The New England Journal of Medicine. It also said Moderna's analyst day on Thursday, November 12, is expected to give a more specific timeline.techtimes.com+1

The key question is still unanswered. "Longer follow-up is needed to show an impact on melanoma-specific and overall survival," Long said.medicalxpress.com