The vaccine, called Intismeran Autogene, targets patients with high-risk melanoma whose tumors have been surgically removed. Moderna, a biotechnology company, is developing the treatment in partnership with Merck, a biopharmaceutical company, according to both firms.
The National Cancer Institute describes melanoma as less common than other major skin cancer types but more likely to invade nearby tissue and spread to other parts of the body. Most deaths from skin cancer are caused by melanoma, the institute noted.
The American Cancer Society estimates roughly 112,000 new cases of invasive melanoma and 8,510 deaths for 2026, figures that underscore the scale of the disease burden the trial seeks to address across the population.
The treatment combines Intismeran Autogene with Merck’s immunotherapy drug Keytruda. The regimen uses up to nine doses of Keytruda given every six weeks, together with up to nine doses of the customized mRNA vaccine designed around a patient’s specific tumor mutations.
Merck describes Intismeran Autogene as an mRNA-based, individualized neoantigen therapy built around the unique mutational signature of each patient’s tumor. The company stated it uses synthetic mRNA coding for up to 34 neoantigens, which are features of cancer cells that help the immune system recognize and attack them.
Unlike chemotherapy, which kills both healthy and cancerous cells, personalized cancer vaccines train the immune system to target mutations specific to a person’s tumor. The approach is designed to direct the body’s own defenses against cancer without harming surrounding tissue.
Five-year data from a Phase 2b trial showed that adding intismeran autogene to Keytruda reduced the risk of cancer returning or death by 49 percent compared with Keytruda alone. Merck stated the combination also cut the risk of cancer spreading to distant parts of the body or death by 59 percent.
Ryan Sullivan, director of the Centre for Melanoma at Mass General Brigham Cancer Institute, described the findings as “a big deal for the field in general.” Sullivan told Reuters that the approach could change the way cancer is treated more broadly and expressed optimism about its potential.
Julie Gralow, Chief Medical Officer of the American Society of Clinical Oncology, described the trial results as “a monumental leap forward,” stating they validate mRNA technology as a cancer treatment platform with applications that could extend well beyond melanoma.
Elizabeth Buchbinder, a melanoma specialist at Mass General Brigham Cancer Institute, said melanoma was chosen for testing partly because it produces many mutations, making it easier for the immune system to identify cancer cells and mount a targeted response against them.
Buchbinder added that many other cancer types also produce multiple mutations, suggesting the approach could have broad applications. “We’ll see, but it’s definitely an area that is going to be exploding, especially with these results coming out,” she was quoted as saying.
Moderna and Merck are already conducting trials of the treatment in non-small cell lung cancer, bladder cancer, and kidney cancer. The companies are also studying the approach in pancreatic and stomach cancers, with results from several trials expected over the next one to two years.
Moderna President Stephen Hoge told Reuters that the expansion of trials reflects growing confidence in the mRNA platform as a foundation for treating multiple cancer types beyond the melanoma indication that produced the current Phase 2b results.
Other companies are also developing similar mRNA cancer vaccines. Roche and BioNTech are testing a comparable treatment called autogene cevumeran in patients with colon and pancreatic cancers who have undergone surgery, broadening the competitive field.
Robert Vonderheide, president-elect of the American Association for Cancer Research, told Reuters: “We should be hearing results from multiple studies over the next few years, and there’s every reason to hope now.” The current melanoma trial remains ongoing, and researchers will continue following participants to determine whether personalized cancer vaccines also extend overall patient survival.
