Overview
- The companies reported on Aug. 19, 2026 that their individualized mRNA vaccine, intismeran autogene, given with Merck’s pembrolizumab met the trial’s primary endpoint for recurrence‑free survival and a key secondary endpoint for distant‑metastasis‑free survival.
- The double‑blind Phase 3 study enrolled about 1,137 patients with completely resected stage IIB–IV high‑risk melanoma and compared Keytruda plus the personalized vaccine to Keytruda alone.
- No new safety signals were reported in the interim readout, but the trial will continue to collect longer‑term outcomes, including whether the vaccine improves overall survival.
- Markets reacted sharply — Moderna’s shares jumped roughly 177% in one session — while analysts warn the stock move may overstate likely sales because of limits on which cancers benefit and high per‑patient manufacturing costs.
- The vaccine is made for each patient by sequencing the tumor and encoding up to about 34 neoantigens, a process that raises questions about lead time, likely high prices (industry estimates near $300,000), and how public mistrust of mRNA could affect uptake.