Moderna shares drop up to 25% despite positive melanoma cancer vaccine data

Moderna (MRNA) shares fell as much as 25% on Thursday, even though its personalized cancer vaccine, Intismeran autogene paired with Merck’s Keytruda, cut melanoma recurrence or death risk by 42% in certain patients. The combination showed an 82% two-year recurrence-free survival rate versus 70% on Keytruda alone, and cut the risk of distant spread or death by 38%. However, the trial covered only one tumor type, and the personalized vaccine production takes six weeks, posing a manufacturing challenge. Full phase 3 results are expected at the ESMO conference this weekend.