Moderna's melanoma vaccine succeeds in major trial. So why did its stock plunge?

Moderna and Merck's personalized melanoma vaccine combined with Keytruda reduces the risk of recurrence or death by 42% in a major Phase 3 trial, marking a significant clinical breakthrough despite Moderna's stock plunging nearly 18% due to unmet investor expectations.

This Wire brief sits within Fusion42's coverage of Biotech, and 6 sources have reported it between 12 Oct 2026 and 24 Oct 2026.