Moderna Inc.'s shares surged nearly 200% on Wednesday after the biotech company and Merck & Co. reported positive results from a late-stage trial of an experimental personalized cancer vaccine. The combined treatment reduced the risk of melanoma recurrence or death by 44% compared with Keytruda alone, according to data shared with investors.
The trial met its primary endpoint of preventing melanoma from returning, with secondary goals also achieved, including halting cancer spread to other parts of the body. The vaccine, developed using Moderna's mRNA technology, identifies patient-specific tumor mutations and encodes up to 34 targets into an mRNA strand designed to train the immune system to attack cancer cells. It is administered alongside Merck's Keytruda immunotherapy.
The announcement added approximately $44 billion to Moderna's market value, nearly tripling its stock price. The company's shares had previously declined more than 90% from its 2021 pandemic peak, and 2023 sales fell by nearly two-thirds. Moderna and Merck first partnered in 2016, committing $200 million to research the combination treatment before agreeing in 2022 to jointly develop and split profits.
Detailed trial results will be presented at a medical conference later in 2026, with U.S. approval targeted for 2027. CEO Stéphane Bancel stated that an approved treatment would cost less than CAR-T therapies, which can exceed $500,000 per patient, though no specific price has been disclosed. The vaccine platform is also being tested in lung, kidney, and pancreatic cancers, though effectiveness metrics and production costs remain undisclosed.
The breakthrough follows over a decade of Moderna's research into mRNA cancer vaccines, reviving investor confidence amid broader biotech sector challenges.
