Moderna and Merck say personalized mRNA melanoma vaccine met Phase III primary endpoint with Keytruda

Moderna and MSD/Merck reported that their personalized mRNA neoantigen vaccine intismeran autogene, given with Keytruda (pembrolizumab), met its primary endpoint in a Phase III adjuvant melanoma trial: statistically significant improvement in recurrence-free survival versus Keytruda alone after complete surgical removal of Stage IIb–IV melanoma. Distant metastasis-free survival, a key secondary endpoint, also improved. The companies reported no new safety signals.

Trial design

The study, INTerpath-001 (NCT05933577), enrolled 1,137 participants. The vaccine is individualized from each patient’s tumor mutations. According to coverage on 25 September 2026, Penn Medicine was a U.S. trial site and was featured in The Philadelphia Inquirer. The companies plan to present full results at ESMO 2026 in Spain.

What is still unknown

Exact hazard ratios and absolute benefit figures have not yet been made public, so clinical meaningfulness awaits the full data package. Manufacturing and access for a fully individualized product remain practical challenges. This topline readout is the first positive Phase III result for an mRNA individualized neoantigen therapy in oncology and the first to show additive benefit over Keytruda alone in adjuvant melanoma, according to the companies’ framing — but peer presentation and scrutiny of the full dataset are still ahead.

Limitations and advice

These findings are preliminary topline results from a Phase III randomized trial; they are not a substitute for the forthcoming detailed analysis. This article is not personal medical advice. Patients considering melanoma treatment should discuss options with an oncology clinician.