An experimental cancer vaccine developed by Moderna and Merck has demonstrated significant promise in preventing the recurrence and spread of melanoma, the deadliest form of skin cancer, according to statements from the pharmaceutical companies. In a large Phase 3 clinical trial involving 1,137 patients whose high-risk melanoma had been surgically removed, those who received the mRNA-based vaccine, known as intisomeran, experienced improved outcomes.
The full results of the study are slated for presentation at an upcoming international medical meeting and will be submitted to regulatory authorities. Researchers not involved in the trial have expressed optimism about the development.
"I think it’s going to be transformational, honestly," said Dr. Ashi Weeraratna, an expert in melanoma metastasis at Johns Hopkins Bloomberg School of Public Health. She noted that the approach is personalized to individual patient mutations. Dr. Elias Sayour, a pediatric oncologist at the University of Florida, also not involved in the trial, told The New York Times that the results "could help usher a whole new wave of new therapeutic treatments for cancer."
The vaccine utilizes mRNA technology, which allows for the rapid development of treatments that train the immune system to identify and attack specific targets, such as cancer cells. This technology was notably employed in the swift creation of COVID-19 vaccines.
Intisomeran is designed specifically for each patient, enabling their immune system to recognize and target the unique mutations of their tumor. If approved, it would be the first vaccine of its kind.
The vaccine was administered in combination with Merck's immunotherapy drug Keytruda. Patients who received both treatments together showed an extended period before their cancer returned compared to those who only received Keytruda. Weeraratna highlighted that mRNA vaccines, in addition to being personalized, generally have few side effects and low toxicity, contrasting with some other immunotherapies that have limited patient response or long-term success.
"Part of that is because cancers come back. It’s what we call tumor dormancy, where basically you can take the bulk of a tumor out, but there are still a few cells that remain, and they may not do anything for a while ... and then they eventually come back," Weeraratna explained. "I think that’s what’s so exciting about this current therapy, is that it actually seems to be reducing the number of tumors that then come back after the initial therapies."
Melanoma affects approximately 8,000 people annually in the U.S. While early detection often leads to successful treatment, relapse remains a concern even for those diagnosed early. The Melanoma Research Foundation indicates a lifetime risk of melanoma of about 1 in 33 for Caucasians, 1 in 200 for Hispanics, and 1 in 1,000 for African Americans. The Melanoma Research Alliance, which has supported some researchers involved in the study, called the results "encouraging news for people affected by melanoma."