Moderna and Merck have reported a milestone in cancer research: their personalized mRNA cancer vaccine, given alongside Merck’s immunotherapy Keytruda, succeeded in a pivotal Phase 3 melanoma trial — the first positive Phase 3 result for an mRNA-based, individualized cancer vaccine.
The trial, called INTerpath-001, enrolled 1,137 patients whose high-risk melanoma (stage IIB–IV) had been surgically removed. Participants received either the vaccine — known as intismeran autogene — plus Keytruda, or Keytruda alone. The combination produced a statistically significant, clinically meaningful improvement in recurrence-free survival (the primary endpoint) and in distant metastasis-free survival (a key secondary endpoint) compared with Keytruda by itself. No new safety signals were seen.
How a personalized vaccine works
These are “neoantigen” vaccines: each is custom-built for an individual patient. Doctors sequence a patient’s tumor to find mutation-specific markers (neoantigens), then design an mRNA vaccine that trains the immune system to recognize and attack cells carrying them. Combining that with a checkpoint inhibitor like Keytruda is meant to unleash a stronger, more targeted anti-tumor response.
Why it matters
Neoantigen cancer vaccines have been an aspiration for years, but this is the first randomized Phase 3 trial aimed at definitively proving the benefit — and it also revives the promise of mRNA technology beyond COVID-19. The companies are expected to move toward regulatory filings. The results are a topline readout; full data and any approval decision are still to come.