Moderna and Merck have announced positive Phase 3 trial results for their personalized mRNA cancer vaccine combined with Merck’s Keytruda. This experimental treatment targets high-risk melanoma that has been surgically removed. The trial met its primary goal of reducing cancer recurrence and its secondary goal of preventing spread. This marks a significant milestone as it's the first positive Phase 3 outcome for a personalized mRNA cancer therapy. It also shows improvement over using Keytruda alone. The personalized vaccine, called Intismeran Autogene, is developed by analyzing a patient's unique tumor mutations. It then trains the immune system to recognize and attack cancer cells. This approach aims to enhance the body's ability to fight cancer. Moderna's stock surged over 120% following the announcement, while Merck's stock increased by 11%. The companies are exploring this treatment for other cancer types, including lung, bladder, and kidney cancer, through nine ongoing trials.