New mRNA Vaccine Reduces Risk of Melanoma Recurrence After Surgery by 42%
13:42 24 October, 2026Adding the experimental personalized cancer vaccine intismeran to immunotherapy with pembrolizumab reduced the risk of melanoma recurrence or death by 42% compared with pembrolizumab alone. This was demonstrated by the international Phase III clinical trial INTerpath-001, the results of which were presented at the 2026 Congress of the European Society for Medical Oncology (ESMO), Medical Xpress reports.
The study involved 1,137 patients with high-risk melanoma, ranging from stage IIB to stage IV, whose tumors had already been surgically removed but who remained at high risk of disease recurrence. None of the participants had received systemic cancer treatment before entering the trial.
The researchers compared outcomes in patients receiving pembrolizumab alone with those receiving the drug in combination with intismeran, an experimental vaccine individually tailored to the characteristics of each patient's tumor. Patients who received the combination therapy had a 42% lower risk of recurrence or death. Among patients whose disease did not recur during the first six months of treatment, the reduction in risk reached 58%.
According to Professor Georgina Long, medical director of the Melanoma Institute Australia and the study's principal investigator, the findings could represent an important step forward in personalized cancer treatment. She noted that this was the first Phase III trial to demonstrate a reduction in the risk of recurrence or death using a therapy developed on the basis of an individual tumor's characteristics.
The vaccine is based on messenger RNA (mRNA) technology. First, specialists analyze a tumor sample to identify its unique neoantigens — protein structures that the immune system can use to recognize cancer cells. A vaccine is then developed based on these findings to help the body identify and attack tumor cells that may remain after surgery. Pembrolizumab complements this action by blocking a mechanism through which tumors suppress the immune response.
Overall, the combination therapy was well tolerated. Adding the vaccine did not increase the frequency of pembrolizumab-related side effects. Reported vaccine-related reactions included temporary injection-site pain, headache and chills.
Intismeran, also known as V940 or mRNA-4157, is being jointly developed by Moderna and MSD (Merck & Co.). Despite the encouraging results, the treatment remains experimental. The data must now undergo regulatory review, a process that could take several years, depending on the country.