Melanoma vaccine shows 42% risk reduction at ESMO 2026, but shares tumble on early data release

Moderna and Merck presented Phase 3 results for their melanoma vaccine intismeran autogene at the European Society for Medical Oncology meeting. The trial reported a 42% reduction in the relative risk of recurrence or death, a result analysts described as clinically meaningful and likely to support approval.

Despite the positive clinical outcome, the data were released before the scheduled conference session, prompting a sharp sell-off in Moderna's stock as investors reacted to the premature disclosure.

The same meeting also featured a lung cancer therapy from Amgen that earned a standing ovation from the audience, highlighting continued enthusiasm for novel oncology candidates.