Merck and Moderna reported success in a pivotal randomized late-stage trial testing intismeran autogene—a personalized mRNA neoantigen vaccine—added to Merck’s Keytruda (pembrolizumab) in resected high-risk melanoma. The companies said the combination met its primary endpoint for recurrence-free survival and improved distant metastasis-free survival, with statistically significant, clinically meaningful effects at an interim analysis. The regimen builds on the partners’ long-running platform for individualized vaccines: tumor sequencing identifies patient-specific neoantigens, and mRNA is manufactured accordingly for administration with Keytruda in the adjuvant setting. Merck and Moderna did not disclose full dataset details in the announcement, but indicated no new safety signals emerged. Separately, additional coverage framed the result as the most advanced checkpoint yet for personalized neoantigen vaccines, setting up a potential approval push if the final trial readouts confirm the durability of benefit.