Pharmaceutical giants Moderna and Merck said Wednesday that an experimental vaccine treatment has shown signs of preventing the cancer from coming back or spreading in a study of high-risk melanoma patients. The companies did not publish their results in a peer-reviewed journal or release the new data, but instead said they 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 had already undergone surgery to remove melanoma, the deadliest form of skin cancer. The study involved a personalized cancer vaccine called Intismeran, produced by Merck and Moderna, given in combination with Merck’s Keytruda cancer immunotherapy. Interim results from the trial show that the vaccine and drug combination appeared to extend the time before cancer returned in high-risk patients, according to the statement, although the companies did not say for how long. In June, Merck and Moderna presented research on the experimental melanoma vaccine at the American Society of Clinical Oncology’s annual meeting, saying at the time that it halved the risk of melanoma returning after five years in a group of 157 patients. Side effects from the vaccine-drug combination were mostly mild or moderate, although some patients had to stop or delay treatment due to adverse reactions. Those findings were published in the Journal of Clinical Oncology. The late-stage study enrolled 1,137 patients who were randomly assigned to receive the vaccine-drug combination or Keytruda alone for about a year. According to the statement, the study did not find any new safety problems. Merck and Moderna described the results as the first breakthrough of their kind. They said the study would continue to examine overall survival rates after treatment. “These Phase 3 findings represent a pivotal moment for the field of cancer research,” Stéphane Bancel, CEO of Moderna, said in the statement. “For many years, the idea of creating an mRNA treatment designed specifically for an individual patient’s cancer was an aspiration. Now we are helping to turn that vision into a reality.” The Covid shots were the first mRNA vaccines to hit the market, and the Food and Drug Administration this month approved the first flu vaccine using mRNA technology, also from Moderna. Decades before those vaccines were available, scientists were exploring the technology as a way to treat cancer. Merck and Moderna have been working on a melanoma vaccine for about a decade. It is designed to train the immune system to identify and eliminate cancer cells. The vaccine targets abnormal proteins called neoantigens that appear on the surface of cancer cells. It can be customized for individual patients using genetic material from their tumors, which researchers hope will lead to longer-lasting immune responses compared to other melanoma treatments. Moderna shares soared as much as 142% in trading on Wednesday. Merck shares rose about 11%. The future of mRNA research has been uncertain under the Trump administration. Health Secretary Robert F. Kennedy Jr. has repeatedly criticized mRNA technology and last year cut $500 million in contracts for mRNA vaccine research and development. Under former FDA vaccine chief Dr. Vinay Prasad, the agency initially rejected Moderna’s application for the mRNA-based flu vaccine, but later changed course.
