Moderna's cancer vaccine boost lifts stock, sparks talk of Keytruda-like reach

Moderna’s shares surged 177% after a phase 3 topline win for its Merck‑partnered cancer vaccine, intismeran autogene, was disclosed. The data, released on Wednesday, added roughly $45 billion to Moderna’s market value.

Analysts at Evercore ISI and William Blair pointed to heightened activity from retail investors and short sellers as contributors to the rally, while Merck’s stock also rose about 13% on the news.

The adjuvant melanoma indication could generate more than $2 billion in sales, according to Guggenheim Securities, but analysts say broader efficacy across other cancer types will be needed to sustain the inflated valuations. Investors are now debating whether the trial data de‑risk intismeran enough to become as widely used as Keytruda.