Personalized mRNA Vaccine Reduces Melanoma Recurrence Risk by 42%

A personalized mRNA vaccine for melanoma reduced the risk of tumor recurrence or death by 42% compared to standard immunotherapy alone, according to phase 3 clinical trial results presented by lead Australian researcher Georgina Long from Australia's Melanoma Institute at the European Society for Medical Oncology conference ESMO 2026, with publication expected in the New England Journal of Medicine.

The vaccine, developed by Moderna and Merck, works following surgical tumor removal. Researchers analyze each patient's tumor genetic sequence and then design a vaccine that presents the immunological "fingerprint" of that specific cancer cell to the immune system. The vaccine is delivered via mRNA, enabling the body's cells to display this fingerprint to the immune system, and works in combination with the immunotherapy drug known as Keytruda — the scientific name pembrolizumab.

The trial included more than 1,100 patients from 157 centers worldwide. Among patients who remained cancer-free six months after beginning treatment, the reduction in recurrence or death risk reached 58% compared to pembrolizumab alone. These results reinforce findings from the phase 2 trial published in 2024.

Robert Funderheid, the president-elect of the American Cancer Research Association — who did not participate in the trial — said the results "stand among the greatest milestones" in the history of oncology. Long affirmed that the vaccine "represents a fundamental transformation" in cancer treatment approach, noting that personalizing therapy for each patient improves the outcomes achieved by pembrolizumab alone.

The vaccine is not yet available to patients in Australia or the United States, and the results are undergoing regulatory agency review.