Personalized mRNA Melanoma Vaccine Cut Recurrence or Death Risk 42% in Phase 3 Trial, but Survival Data Pending

A Phase III trial showed that intismeran autogene, a personalized mRNA therapy, combined with pembrolizumab, reduced the risk of death or recurrence by 42% in high-risk melanoma patients. The study, presented at ESMO 2026, enrolled 1,137 patients and demonstrated improved recurrence-free and distant metastasis-free survival. Despite the positive clinical results, a data leak caused shares of manufacturers Moderna and Merck to fall.

Moderna and Merck's personalized mRNA cancer vaccine, combined with pembrolizumab, reduced melanoma recurrence or death risk by 42% in a Phase III trial with 1,137 patients. After two years, 82.2% of vaccine group patients were alive without recurrence, versus 70.0% with pembrolizumab alone. The vaccine targets individual tumor mutations, showing broader applicability in high-risk melanoma.

Moderna's stock fell over 1% after Phase 3 melanoma vaccine trial data showed a 42% reduction in recurrence or death risk. Analysts had mixed reactions, with price targets ranging from $80 to $137. The trial, conducted with Merck, involved 1,137 participants and reported side effects like fever and fatigue. Full data will be presented at a cancer conference in Madrid.

Moderna and Merck's Phase 3 trial of personalized melanoma vaccine intismeran autogene with Keytruda showed a 42% reduction in recurrence or death risk vs. Keytruda alone. Two-year recurrence-free survival was 82.2% for the combination vs. 70.0% for Keytruda alone. The combination had more adverse events. Specialists called results clinically meaningful but not yet establishing longer life. Moderna shares fell 17.57% following the release.

Moderna (MRNA) reported Phase 3 results showing its melanoma combo vaccine with Keytruda reduced recurrence/death risk by ~42% and distant metastasis by ~38%. The EU and FDA approved other Moderna vaccines. Analysts had mixed reactions: Citi reiterated a Sell rating, Bernstein maintained Market Perform with a $45 target, and TD Cowen kept Hold with a $90 target. MRNA stock showed volatility.

Moderna (MRNA) and Merck reported a 42% reduction in melanoma recurrence or death in a Phase 3 trial of Moderna's cancer vaccine. Shares fell 17.6% after data leaked early. The trial tested intismeran autogene with Merck's Keytruda. Moderna reported Q2 2026 loss of $782m on $145m revenue.