Moderna and Merck announced positive results from a late-stage trial of their experimental melanoma vaccine on August 19, 2026, sending their shares sharply higher. Moderna shares jumped between 90% and 177% while Merck shares rose 7% to 12.6% on the news [1, 2, 3].
The vaccine combines Moderna's mRNA technology with Merck's immunotherapy drug Keytruda. It trains the immune system to target tumor mutations, a method distinct from chemotherapy which attacks cancer cells more broadly [2, 3]. More than 1,100 patients with high-risk melanoma that had been surgically removed participated in the trial. Results showed clinically meaningful improvement over Keytruda alone [3]. The safety profile was consistent with earlier studies, with no new risks identified [3].
The trial marks the first successful late-stage study for an mRNA-based cancer therapy [2]. Stephen Hoge, Moderna president, said, "People will experience this as ... the COVID company now [takes on] cancer," adding the company "pivoted back and really finally come home" [3]. William Soliman, founder and CEO of the Accreditation Council for Medical Affairs, said, "We may be entering an era where a patient's individual tumor biology can be used to design a therapy specifically for them." TD Cowen analysts called it "a landmark moment" and "a significant validation of the ... platform" [3].
Moderna co-founder Robert Langer's stake value doubled from $730 million to an estimated $1.7 billion on August 19 due to the share price surge. Other Moderna insiders also saw net worth jumps: co-founder Noubar Afeyan to $2.1 billion, CEO Stéphane Bancel to $4.8 billion, and investor Timothy Springer to $2.2 billion [2].
Moderna’s melanoma vaccine could launch commercially as soon as 2027 and may be adapted for other cancers including kidney, bladder, and pancreas tumors [3]. The companies will likely advance regulatory filings and preparations for potential 2027 rollout next.
