Personalized mRNA vaccine cuts melanoma recurrence risk by 42%

Merck and Moderna said a personalized mRNA vaccine added to pembrolizumab reduced the risk of melanoma recurrence or death by 42% in a phase III trial involving 1,137 patients whose high-risk tumors had been surgically removed. The INTerpath-001 trial compared pembrolizumab alone with the combination of pembrolizumab and intismeran, also known as mRNA-4157. The reported 42% reduction concerns relative risk, not the percentage-point difference in the proportion of patients who remained recurrence-free. The trial results were presented at the European Society for Medical Oncology Congress in 2026. At two years, 82.2% of patients receiving the combination remained recurrence-free, compared with 70% of those given pembrolizumab alone, according to figures reported by Melanoma Institute Australia. The combination was also associated with a 38% reduction in the relative risk of distant metastasis or death. One account of the findings reported a 49% reduction in recurrence or death over three years. The other trial reports cited a 42% reduction, with one specifying a two-year follow-up. The supplied accounts do not explain the difference between the estimates, so the 49% figure...