mRNA therapy for melanoma: companies report 42% lower risk of relapse

An mRNA therapy tailored to each individual patient's tumor could better protect people with melanoma from relapse after surgery. That is what drugmakers Merck (known as MSD outside the U.S. and Canada) and Moderna reported on Oct. 22, 2026, from the Phase 3 INTerpath-001 trial. The trial tested the investigational drug intismeran autogene in combination with the immunotherapy Keytruda (pembrolizumab) in 1,137 patients with completely removed stage IIB to IV melanoma. According to the companies, after a median of 24.6 months the combination reduced the risk of recurrence or death by 42% compared with Keytruda alone (hazard ratio 0.58; 95% confidence interval 0.45–0.75).

After two years, 82.2% of patients in the combination group were free of recurrence, compared with 70.0% in the comparison group, the companies said. The risk of distant metastasis or death fell by 38% (hazard ratio 0.62; 95% CI 0.45–0.85). In the first six months, efficacy was comparable with Keytruda alone, according to the companies; the benefit emerged afterward. Overall survival data are not yet mature, according to the companies. For each patient, a tumor sample is used to make an individual mRNA that encodes up to 34 tumor-specific features (neoantigens) and is meant to train the immune system against the cancer cells. Severe treatment-related side effects (grade 3 to 5) occurred in 14.2% versus 13.4%; the most common adverse events in the combination group were fever, injection-site pain and fatigue.

"The transformative INTerpath-001 results have the potential to make a foundational shift in how we treat patients with earlier-stage melanoma," said principal investigator Georgina Long, medical director of Melanoma Institute Australia. The data are to be presented at the European Society for Medical Oncology (ESMO) 2026 congress and have been accepted for publication in The New England Journal of Medicine, according to the companies. The figures are company data; an independent assessment is pending. The therapy is not yet approved – Merck and Moderna said they are engaging with regulatory authorities. Treatment decisions are always up to the medical team.