Moderna-Merck Cancer Vaccine Breakthrough Sends Stocks Soaring

Moderna and Merck's experimental cancer vaccine has shown promising results in its first late-stage trial, sending stocks soaring on Wednesday morning.

The mRNA shot, combined with Merck's immunotherapy Keytruda, met the key goals in over 1,100 patients with advanced-stage melanoma. The combination extended the time patients lived without their melanoma returning compared to Keytruda alone and reduced the risk of cancer spreading.

Melanoma cases have been rising over the past few decades, with an estimated 112,000 new cases diagnosed in the U.S. during 2026. Despite advances in treatment, patients with surgically removed melanoma remain at risk for disease recurrence.

Moderna's stock surged over 90%, while Merck's shares climbed more than 9% in morning trading. The companies plan to present the data at an upcoming international meeting.