Moderna and Merck detail melanoma vaccine trial results amid market volatility

Moderna and Merck have released data from a phase‑3 study of a personalized mRNA melanoma vaccine given with Merck’s Keytruda, involving 1,137 high‑risk patients whose tumors were surgically removed. The companies said the combination extended both recurrence‑free and distant‑metastasis‑free survival compared with Keytruda alone, with side effects described as mild. The announcement followed an internal meeting in 2023 where CEO Stéphane Bancel asked executives to stand if they expected success, an invitation only briefly answered by President Stephen Hoge. While the news sparked a sharp rise in Moderna’s share price, the stock later fell more than 25%, and some observers note the lack of published trial data and continued skepticism toward mRNA cancer therapies.