Merck and Moderna report personalized mRNA vaccine delays melanoma recurrence in late-stage trial

Merck and Moderna announced that a personalized mRNA cancer vaccine, when combined with standard therapy, slowed the return of melanoma and reduced its spread in a late-stage clinical study. The trial added the vaccine to patients already receiving existing treatment, and investigators observed a measurable delay in disease progression.

The data come from a late-stage trial that followed participants after earlier promising signals in 2024. While the companies did not release detailed numbers, they described the results as encouraging and indicative of a new therapeutic direction in oncology.

If the findings are confirmed in further analysis, the vaccine could represent a significant advance for melanoma patients and potentially reshape how mRNA technology is applied in cancer care.