A novel mRNA cancer vaccine helps cut the chances of melanoma tumor recurrence in major study

A first-of-its-kind cancer vaccine is significantly reducing the chances that melanoma patients' tumors come back, according to results of a major study released Thursday by drugmakers Moderna and Merck.

The vaccine was custom-brewed for each patient to match their tumor. Adding it to a standard post-surgery treatment reduced by 42 per cent the risk of melanoma returning two years after surgery, according to the most advanced study to date of this new strategy for fighting cancer.

"This is a new frontier," said Karen Knudsen, CEO of the Parker Institute, which helps fund cancer immunotherapy research.

The Associated Press · Lauran Neergaard · Posted: Oct 23, 2026