Merck and Moderna's Personalized mRNA Cancer Vaccine Succeeds in Phase 3 Melanoma Trial
On August 19, 2026, Merck and Moderna announced positive topline results from the Phase 3 INTerpath-001 trial evaluating adjuvant treatment with intismeran autogene (V940 or mRNA-4157), an investigational mRNA-based individualized neoantigen therapy (INT), in combination with Keytruda (pembrolizumab) in patients with completely resected Stage IIB-IV cutaneous melanoma. This represents the first positive Phase 3 readout for an individualized neoantigen therapy and for an mRNA-based cancer therapy, demonstrating statistically significant and clinically meaningful improvements in recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) compared to Keytruda alone.
The trial enrolled 1,137 patients who were randomized 2:1 to receive either the combination therapy or single-agent Keytruda for approximately one year following complete surgical resection.
Key Perspectives and Findings
Professor Georgina Long, the study’s principal investigator and medical director of Melanoma Institute Australia, highlighted the transformative nature of the results:
"Today’s results represent a landmark moment for adjuvant melanoma treatment. This is the first Phase 3 study to show that intismeran, a treatment designed based on the unique mutational ‘fingerprint' of a patient's own tumor, given in combination with pembrolizumab can reduce the risk of recurrence or death in patients with completely resected stage IIB-IV melanoma compared to KEYTRUDA alone."
Dr. Dean Y. Li, president of Merck Research Laboratories, emphasized the implications for personalized oncology:
"These first Phase 3 findings for intismeran in combination with KEYTRUDA as adjuvant therapy reinforce the promise of a more personalized approach to cancer treatment. We believe individualized neoantigen therapies have the potential to redefine how patients with completely resected stage IIB-IV melanoma are treated."
The safety profile of the combination therapy was consistent with earlier Phase 2b results, showing no new safety signals. The companies plan to present the full dataset at an upcoming international medical meeting and will engage with global regulatory authorities to discuss filing for marketing approvals.