October 26, 2026 —
A phase 3 trial of intismeran autogene plus Keytruda cut the risk of recurrence or death by 42% versus Keytruda alone in patients with completely resected stage IIB to IV melanoma, Georgina V. Long of Melanoma Institute Australia reported on October 24 at the European Society for Medical Oncology (ESMO) Congress 2026. The data mark the first positive phase 3 results for an individualized mRNA-based cancer therapy in the adjuvant setting.
< h2> Trial Design and Patient Population
The INTerpath-001 study randomized 1,137 patients with completely resected high-risk stage IIB-IV melanoma in a 2:1 allocation. One group received intismeran autogene plus Keytruda; the other received placebo plus Keytruda. All participants had undergone complete surgical resection. Intismeran autogene is an mRNA-based individualized neoantigen therapy (V940/mRNA-4157) jointly developed by Merck and Moderna. Patients received nine intramuscular doses of intismeran in addition to intravenous pembrolizumab every six weeks.
< h2> Efficacy Endpoints: Recurrence and Distant Metastasis
At a data cutoff of June 30, 2026, with a median follow-up of 24.6 months, the recurrence-free survival hazard ratio was 0.58 (95% CI, 0.45–0.75), translating to a 42% lower risk of recurrence or death in the combination arm. Two-year recurrence-free survival rates were 82.2% for patients receiving intismeran plus Keytruda and 70.0% for those on Keytruda plus placebo. Distant metastasis-free survival yielded a hazard ratio of 0.62 (95% CI, 0.45–0.85); two-year distant metastasis-free survival rates were 88.5% versus 80.2%.
< h2> Safety and Treatment Discontinuation
Grade 3–5 treatment-related adverse events occurred in 14.2% of the intismeran plus Keytruda group and 13.4% of the Keytruda-only group. Discontinuation due to side effects was reported in 14.0% of the combination arm and 8.7% of the pembrolizumab-alone arm. The safety profile was generally consistent with the known profiles of the individual agents, and no new safety signals emerged from the trial population.
< h2> Subgroup Consistency and Regulatory Outlook
Benefit was observed across prespecified subgroups defined by disease stage and patient age, with the risk reduction emerging after approximately six months of treatment. Overall survival data remain immature and did not reach statistical significance (HR 0.77; 95% CI, 0.45–1.31). Merck and Moderna intend to engage with regulatory authorities regarding filing submissions for intismeran autogene in combination with Keytruda for this patient population. The earlier phase 2b KEYNOTE-942 trial, which included 157 patients, had shown a recurrence-free survival hazard ratio of 0.51, providing a foundation for the phase 3 design.
What it means for patients
The results have been accepted for publication in The New England Journal of Medicine. Intismeran is not yet approved anywhere, and it has been tested only in melanoma that was fully removed by surgery. It is still too early to say whether patients live longer. For people with high-risk melanoma, the data are a real step: one in eight more patients was free of recurrence at two years than with Keytruda alone. Patients should ask their oncologist whether a clinical trial or current approved treatment fits their case.
Sources
- INTerpath-001 Data Detail Survival, Subgroup, and Safety Findings in Melanoma | CancerNetwork
- Intismeran Plus Pembrolizumab Reduces Recurrence Risk in Resected Melanoma | CancerNetwork
- New Personalised mRNA Therapy Improves Melanoma Outcomes: ESMO 2026
- Merck and Moderna Will Present Results From Landmark Phase 3 INTerpath-001 Trial for Intismeran Autogene Plus KEYTRUDA® (pembrolizumab) at ESMO 2026 Presidential Symposium – Merck.com
- Merck and Moderna Announce Phase 3 INTerpath-001 Trial of Intismeran Autogene Plus KEYTRUDA® Met Endpoints of Recurrence-Free Survival (RFS) and Distant Metastasis-Free Survival (DMFS) in Patients With Completely Resected Stage IIB-IV Melanoma – Merck.com
Photo: Julia Koblitz / Unsplash (Unsplash License)
