Combining the personalized cancer vaccine mRNA-4157 (V-940, Moderna Inc.) with Keytruda (pembrolizumab, Merck & Co. Inc.) significantly extended recurrence-free survival in patients with stage III/IV resected high-risk melanoma in the randomized phase II KEYNOTE-942/mRNA-4157-P201 trial. Compared to Keytruda alone, adding the vaccine cut the risk of recurrence or death by 44% 18 months after treatment, lead investigator Jeffrey Weber reported at the opening clinical trials plenary of the 2023 annual meeting of the American Association for Cancer Research (AACR).