Melanoma Vaccine Cuts Cancer Risk in Half, Five-Year Study Shows

After five years, the numbers tell a striking story: nearly 7 in 10 melanoma patients who received a personalized vaccine alongside immunotherapy remained cancer-free, compared to just under half of those on immunotherapy alone. That’s not a marginal improvement—it’s a meaningful shift in how we might fight one of skin cancer’s most aggressive forms.

The study, led by researchers at New York University’s Perlmutter Cancer Center, tested intismeran, an mRNA vaccine tailored to each patient’s tumor, combined with pembrolizumab (Keytruda), a standard immunotherapy drug. The results, presented June 1 at the 2026 annual meeting of the American Society of Clinical Oncology in Chicago and published simultaneously in the Journal of Clinical Oncology, showed a 49 percent reduction in recurrence or death risk—and a striking 59 percent reduction in the spread of cancer to distant sites. Overall survival climbed to 92.2 percent for the combination group versus 71.3 percent for immunotherapy alone.

Here’s what makes this work: the vaccine is built from each patient’s specific tumor. After surgery removes the cancer, researchers analyze the cells for 34 neoantigens—unusual proteins unique to that individual’s melanoma—and craft a personalized mRNA vaccine to teach the immune system to recognize and attack any remaining cancer cells trying to hide or spread. It’s precision medicine in its truest sense. Pembrolizumab, meanwhile, removes the“off switch”cancer cells use to evade the immune system, making those cancer cells visible targets once again. Together, they’re more powerful than either alone.

This matters because melanoma cells are slippery. They’re known for dodging the immune system, and some become resistant to immunotherapy on its own. The vaccine-plus-drug approach addresses that resistance head-on. Dr. Janice Mehnert, senior investigator and director of the melanoma medical oncology program at Perlmutter Cancer Center, called the findings“strong evidence”that this combination can demonstrably reduce recurrence risk and improve outcomes. She also noted that the approach could work for other hard-to-target cancers with high mutation rates—a hint that this breakthrough might extend well beyond melanoma.

A phase 3 trial is already underway to test intismeran as a first-line therapy alongside pembrolizumab, and researchers are exploring whether the vaccine prevents recurrence of lung and other cancers. The stakes are real: skin cancer is the most common form of cancer in the United States, with an estimated 112,000 new cases expected in 2026. While melanoma deaths have declined sharply in the past decade thanks to treatment advances, a personalized vaccine that cuts risk nearly in half could reshape survival rates even further.