Merck and Moderna announced Wednesday that a personalized mRNA-based cancer vaccine succeeded in a large, late-stage trial among high-risk patients who had mela

Merck and Moderna announced Wednesday that a personalized mRNA-based cancer vaccine succeeded in a large, late-stage trial among high-risk patients who had melanoma — a dangerous type of skin cancer. The individualized vaccine, when paired with the existing immunotherapy, Keytruda, is the first an…