Moderna and Merck announced positive Phase 3 trial results for a personalized mRNA cancer vaccine combined with Keytruda, significantly reducing recurrence and metastasis risk in melanoma patients. While this represents a major breakthrough for mRNA technology in oncology, full trial data (particularly overall survival metrics) remain unreleased. The announcement drove Moderna's stock up 159% intraday, reflecting strong investor confidence in mRNA-based cancer therapeutics.