“Moderna's personalized mRNA melanoma cancer vaccine (intismeran, mRNA-4157/V940), developed with Merck and tested alongside Keytruda in a 1,137-patient Phase 3 trial, has shown positive late-stage results and succeeded in the Phase 3 trial”

The sponsors' own announcement confirms the central claim. Merck and Moderna announced positive topline results from the Phase 3 INTerpath-001 trial evaluating adjuvant treatment with intismeran autogene (intismeran; V940 or mRNA-4157), an investigational mRNA-based individualized neoantigen therapy, in combination with Keytruda (pembrolizumab) in patients with completely resected stage IIB-IV melanoma, and the trial met its primary endpoint of recurrence-free survival (RFS) and a key secondary endpoint of distant metastasis-free survival (DMFS). The companies describe this as the first positive Phase 3 readout for an individualized neoantigen therapy. The enrollment figure in the claim matches the release. INTerpath-001 is a randomized, double-blind, placebo- and active-comparator-controlled global Phase 3 trial (NCT05933577) evaluating intismeran plus Keytruda versus Keytruda alone in high-risk resected cutaneous melanoma, and it enrolled 1,137 patients who after complete surgical resection were randomized 2:1 to intismeran 1 mg every three weeks for up to nine doses plus Keytruda 400 mg every six weeks, versus Keytruda alone. Safety and next steps: the safety profiles of intismeran and pembrolizumab in this trial were consistent with those observed in previously reported studies for the combination, with no new safety signals observed. The companies plan to present data at an upcoming international medical meeting and will engage with regulators on filing submissions. The efficacy magnitude has not been disclosed. Interim results met both goals, detailed results have not been released but are expected at an upcoming medical meeting. Intismeran autogene remains investigational and is not approved; the companies said they will engage with regulators on filing submissions, a step that precedes any review or approval decision. On survival: whether it helps people live longer is unknown, overall survival is a secondary endpoint still being evaluated and the trial is continuing in order to measure it, and the companies did not release the size of the benefit. The hazard ratios circulating in coverage come from the earlier Phase 2b study, not from this Phase 3. The phase III readout builds on previously reported phase IIb results from KEYNOTE-942/mRNA-4157-P201, including five-year follow-up presented at the 2026 ASCO Annual Meeting, in which the combination demonstrated a 49% reduction in the risk of recurrence or death (HR 0.51, 95% CI 0.294 to 0.887) and a 59% reduction in the risk of distant metastasis or death (HR 0.411, 95% CI 0.200 to 0.843) compared to pembrolizumab alone. On the caption's "melanoma may only be the beginning" line: the INTerpath program currently consists of nine total phase II and phase III trials across multiple tumor types, including melanoma, non-small cell lung cancer, bladder cancer, and renal cell carcinoma. On the stock overlay: Moderna closed at $174.38 on August 19 2026, up 176.97%, after Moderna and Merck reported positive Phase 3 melanoma data. That move did not hold. Moderna shares fell 20% in early trading on Thursday after the 177% gain, and the stock's previous close was later recorded at $133.32 with a 52-week high of $176.66 set on 08/19/26.