Merck and Moderna say cancer vaccine shows promise in preventing recurrence of melanoma

BREAKING NEWSAug. 19, 2026, 1:15 PM UTCHealth newsHealth newsMerck and Moderna say cancer vaccine shows promise in preventing recurrence of melanomaThe companies have not published the trial data but said in a press release that the experimental treatment extended the time before cancer returned in high-risk patients.Listen to this article with a free profile00:0000:00A researcher works in the lab at the Moderna headquarters in Cambridge, Mass. Adam Glanzman / Bloomberg via Getty Images fileShareAdd to GoogleBy Rob WilePharmaceutical giants Moderna and Merck said Wednesday that an experimental vaccine treatment has shown signs of preventing cancer from returning or spreading in a study of high-risk melanoma patients.The companies have not published their results in a peer-reviewed journal, nor did they release the new data, saying instead that it will be presented at an upcoming medical meeting and shared with regulators.According to a press release, the mRNA-based vaccine was tested in a late-stage trial involving people who’d already had surgery to remove a melanoma, the deadliest form of skin cancer. The study involved a personalized cancer vaccine called Intismeran, produced by Merck and Moderna, used in combination with Merck’s cancer immunotherapy Keytruda. Interim results from the trial show that the vaccine-drug combo appeared to extend the time before cancer returned in high-risk patients, according to the release. The companies described it the first-ever breakthrough of its kind. They said the study would continue to examine overall survival rates following the treatment. “These Phase 3 findings represent a pivotal moment for the field of cancer research,” said Stéphane Bancel, CEO of Moderna, said in a news release. “For many years, the idea of creating an mRNA treatment designed specifically for an individual patient’s cancer was aspirational. We are now helping turn that vision into a reality.” Moderna shares soared as much as 106% in pre-market tradin...