Moderna Surges 177% in Best Day Ever After mRNA Cancer Vaccine Succeeds in Phase 3 Trial

Moderna shares soared 177% on Wednesday, their best single-day gain on record, adding roughly $44 billion in market cap and lifting the stock from a prior close of $62.96 to as high as the $160s intraday, after the company and partner Merck announced positive topline results from their Phase 3 INTerpath-001 trial. The study tested intismeran autogene, an individualized mRNA-based neoantigen therapy branded as V940 or mRNA-4157, in combination with Merck's immunotherapy Keytruda in more than 1,100 patients with completely resected Stage IIB-IV melanoma. The trial met both primary endpoints, significantly extending recurrence-free survival and distant metastasis-free survival compared with Keytruda alone, and was stopped at its first interim analysis following the positive read.

It marks the first time any mRNA-based personalized cancer vaccine has succeeded in a late-stage trial, validating decades of research into the technology. Moderna CEO Stephane Bancel said the company is targeting regulatory approval by 2027. Merck shares jumped roughly 12% on the news, touching all-time highs, and the result sparked a broad biopharma rally with Amgen up 3.7%, Eli Lilly up 4%, and AbbVie gaining 2.6%.

William Blair upgraded Moderna to Outperform. Personalis, which sequences tumors for neoantigen vaccine design, rose more than 6% in sympathy. An options contract on Moderna that was far out of the money before the announcement gained more than 700,000% on the day.