Experimental vaccine delays melanoma recurrence, Moderna and Merck report

Moderna and Merck announced Wednesday that an experimental therapeutic vaccine significantly reduced the risk of melanoma recurrence and metastasis in patients considered at high risk for the disease’s return. The vaccine, which combines Moderna’s messenger RNA (mRNA) platform with Merck’s checkpoint‑inhibitor technology, was evaluated in a multicenter, randomized trial involving adults who had undergone surgical removal of stage IIIB–IV melanoma and were deemed likely to experience a relapse.

The phase II study enrolled 210 participants, assigning them to receive either the vaccine plus standard adjuvant therapy or standard therapy alone. At a median follow‑up of 18 months, the vaccine group exhibited a 45 % lower incidence of disease recurrence and a 38 % reduction in distant metastasis compared with the control arm, with a hazard ratio of 0.55 (95 % CI 0.34–0.89). Safety data showed no unexpected adverse events, and the most common reactions were mild injection‑site pain and fatigue. The companies said the results will inform the design of a larger phase III trial slated to begin later this year, aiming to confirm the vaccine’s efficacy and potentially expand its use as an adjuvant treatment for high‑risk melanoma patients.