Moderna stock jumps 177% after melanoma vaccine trial cuts recurrence
Why it matters: The late-stage result is the first large mRNA cancer-vaccine success and could widen Moderna beyond its fading Covid business.
Moderna shares soared 177% after the company and partner Merck & Co reported that their personalized melanoma vaccine reduced cancer recurrence in a late-stage trial. The move dealt short sellers an estimated $5.5 billion paper loss in a single day, according to S3 Partners, and lifted their mark-to-market losses for 2026 to about $7.7 billion.
The result marks the first time an mRNA-based cancer vaccine has succeeded in a large-scale study, a milestone for a technology better known for Covid-19 shots. Analysts said the data could give Moderna a clearer path to diversify revenue beyond its shrinking coronavirus vaccine business. The company’s shares had already risen this year on hopes for its flu and oncology pipeline after years of declines from its 2021 peak.