After bringing to market one of the world’s first COVID-19 vaccines, Moderna spent years watching its stock price steadily crumble. Sputtering sales, slashed revenue projections and trouble finding another lucrative product eroded investor confidence in the company’s direction. For much of 2025, shares once worth more than $400 apiece changed hands at less than $30.
An emerging kind of individualized cancer vaccine Moderna is developing with Merck & Co. appears to have restored Wall Street’s faith. On Wednesday, the partners said their vaccine, intismeran, succeeded in a highly anticipated Phase 3 trial in melanoma. While they didn’t disclose specific data, the findings nonetheless suggest that intismeran could become a multibillion-dollar melanoma treatment and potentially work against other tumors, too.
“This is a major win,” wrote RBC Capital Markets analyst Trung Huynh in a note to clients Wednesday.
The results represent a "landmark moment,” added TD Cowen analyst Tyler Van Buren, in a separate note.
Moderna’s share price rocketed by more than 170%, adding nearly $45 billion to the company’s market value in a single day. Shares of partner Merck and Moderna rival BioNTech, which is working on similar kinds of vaccines, also spiked by double digits. Some analysts revised their revenue projections for intismeran and expressed newfound optimism in the plethora of other trials Moderna and Merck are running. Yet others warned that investors’ euphoric response overshot intismeran’s actual sales potential — and may have overestimated the vaccine’s therapeutic impact, too.
