A personalized mRNA vaccine combined with immunotherapy reduced the risk of melanoma recurrence or death in a Phase 3 clinical trial, according to results released by Merck and Moderna. The experimental treatment is intended for patients whose tumors have already been removed, not for preventing melanoma.
The INTerpath-001 study enrolled 1,137 people with high-risk melanoma following surgery to remove their tumors. Participants received either pembrolizumab, an immunotherapy drug that helps the immune system recognize cancer cells, or pembrolizumab plus the vaccine, called intismeran autogene. Researchers followed patients for an average of 24.6 months.
Compared with pembrolizumab alone, the combination reduced the risk of recurrence or death by 42 percent and the risk of cancer spreading to other parts of the body by 38 percent. At the end of follow-up, 82.2 percent of patients receiving both treatments remained free of recurrence, compared with 70 percent in the immunotherapy-only group.
The vaccine is made individually using a sample of each patient’s tumor. Scientists identify mutations that produce proteins distinguishable by the immune system, then select up to three molecular signatures to help it recognize cancer cells. Trial participants reported side effects including fever, fatigue and injection-site pain; the companies said the combination showed a safety profile similar to earlier studies.
Researchers and independent specialists described the findings as a step forward for personalized cancer treatment. However, the vaccine remains under investigation and requires regulatory approval before it can be widely used. Independent melanoma researcher Marisol Soengas cautioned that producing an individualized vaccine for many patients could be logistically difficult and costly. Although researchers say the approach might eventually be applicable to other cancers, the reported results concern patients with high-risk melanoma after surgery. Further evaluation will determine whether the benefits persist over longer follow-up and how the treatment could be delivered at scale.