Moderna and Merck Report Positive Phase 3 Results for Individualized mRNA Cancer Vaccine in Melanoma

Aug 19, 2026 —

Moderna and Merck have reported that their individualized messenger RNA (mRNA) cancer vaccine met its primary endpoint in a Phase 3 trial in melanoma, delaying disease recurrence and reducing spread following surgery when combined with Merck’s immunotherapy Keytruda.

Independent data monitors reported statistically significant and clinically meaningful improvements for the vaccine plus Keytruda compared with Keytruda alone at a pre-planned interim analysis. Detailed results were not released but are expected at an upcoming medical meeting.

The vaccine, intismeran autogene, is described as an individualized antigen therapy that uses mRNA technology to target up to 34 neoantigens on a patient’s tumor cells, tailored to their disease through biological profiling. The Phase 3 INTerpath-001 trial enrolled 1,137 patients in the adjuvant setting — additional treatment given after a primary treatment such as surgery — with two-thirds randomized to the combination. In an earlier Phase 2 study of 157 patients, the combination reduced the relative risk of death or recurrence by 44% versus Keytruda alone.

Cancer vaccines have attracted substantial investment over decades of research with limited clinical success, which experts have attributed in part to earlier vaccines targeting a single antigen. The companies are also evaluating the therapy in lung, kidney, and bladder cancers, with additional data anticipated in the coming months.