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

The companies haven’t published the trial data, but they said the experimental treatment extended the time before cancer returned in high-risk patients.

Pharmaceutical 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 or released the new data, saying instead that they will be presented at an upcoming medical meeting and shared with regulators.

According to a news 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, administered 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, though 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 of the vaccine-drug combo were mostly mild or moderate, though some patients had to discontinue or delay the treatment due to adverse reactions. Those findings were published in the Journal of Clinical Oncology.