Merck and Moderna announced a randomized Phase 3 success for their personalized neoantigen mRNA vaccine intismeran autogene (intismeran) combined with Keytruda in adjuvant melanoma. The companies said the regimen met its primary endpoint of recurrence-free survival improvement and also improved distant metastasis-free survival, setting up potential regulatory discussions. In the interim analysis described in public statements, the therapy reduced the odds of recurrence or death versus control and produced a separation in key outcomes intended for an approval path. The companies characterized the results as statistically significant and clinically meaningful, while noting that full details will follow in scientific publication processes. The readout marks a “first randomized Phase 3” aimed at definitively validating personalized neoantigen vaccines in melanoma, a program that ties platform manufacturing and patient-specific neoantigen selection to conventional checkpoint therapy. If confirmed after full datasets, it could reshape how developers design next-generation autogene-style vaccine trials across solid tumors.