Moderna’s Cancer Vaccine Trial Data Raises Concerns Among Investors

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.

Moderna and Merck's experimental melanoma vaccine, combined with Keytruda, reduced recurrence or death risk by 42% in a Phase 3 trial. Despite positive results, Moderna's shares fell 18%, likely due to high investor expectations. The vaccine is personalized using mRNA technology, targeting unique tumor mutations. Trial data showed 82.2% of patients treated with the vaccine and Keytruda were alive without recurrence after two years, compared to 70% with Keytruda alone.

Moderna and Merck reported late-stage trial results showing their personalized mRNA melanoma vaccine, intismeran, reduced relapse risk by 42% when combined with Keytruda. The trial involved 1,137 patients, with 82% of vaccine recipients showing no recurrence after two years, compared to 70% for the placebo group. The companies plan to present the findings at a medical conference and continue long-term studies.

Moderna's cancer vaccine trial showed a 42% reduction in melanoma recurrence risk when combined with immunotherapy, but investors reacted negatively, causing shares to drop 19%. Analysts noted the results fell short of expectations. Merck, the co-developer, faces challenges as Keytruda's patent nears expiration. Experts highlight cost and patient-specific factors in treatment decisions.