Moderna and Merck’s personalized mRNA cancer vaccine, intismeran autogene, reported Phase 3 melanoma data showing a 42% reduction in the risk of relapse or death versus pembrolizumab alone, according to trial reports accepted for publication in the New England Journal of Medicine. The study enrolled 1,137 patients with high-risk melanoma and evaluated the combination against pembrolizumab monotherapy. The dual regimen also reduced the risk of distant spread or death by 38% over a median follow-up of about two years, with overall survival not yet reported. Following a data leak earlier in the day, Moderna and Merck said they are engaging with regulators to seek approval, positioning the results as a key milestone for mRNA-based individualized oncology. The trial was also framed as a potential opening for applying the neoantigen approach beyond melanoma. Market reaction reflected investors’ expectations even as clinicians called the efficacy signal clinically meaningful, emphasizing that longer-term endpoints and quality-of-life outcomes remain the next data to watch.