Doctors Call Moderna-Merck Melanoma Vaccine Trial Results Meaningful

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.

Merck (MRK) will acquire Silence Therapeutics (SLN) for $1.3B, or $20 per ADS, an 82% premium. Silence's Phase 3-ready siRNA therapy for polycythemia vera will join Merck's pipeline. The deal, expected to close in Q1 2027, aims to boost Merck's rare disease portfolio and aligns with its specialty healthcare strategy.