On August 19, 2026 Merck (NYSE: MRK), known as MSD outside of the United States and Canada, and Moderna, Inc. (NASDAQ: MRNA) reported positive topline results from the Phase 3 INTerpath-001 trial evaluating adjuvant treatment with intismeran autogene (intismeran; V940 or mRNA-4157), a novel investigational mRNA-based individualized neoantigen therapy (INT) being jointly developed by Merck and Moderna, in combination with KEYTRUDA (pembrolizumab), Merck’s anti-PD-1 therapy, in patients with completely resected stage IIB-IV melanoma. The trial met its primary endpoint of recurrence-free survival (RFS) and a key secondary endpoint of distant metastasis-free survival (DMFS). This represents the first positive Phase 3 readout for an individualized neoantigen therapy (INT) and for an mRNA-based cancer therapy, as well as the first Phase 3 study to demonstrate a clinically meaningful improvement over KEYTRUDA alone, a standard-of-care immunotherapy, in the adjuvant setting for patients with resected melanoma.

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At a pre-specified interim analysis, intismeran in combination with KEYTRUDA as adjuvant therapy demonstrated statistically significant and clinically meaningful improvements in RFS and DMFS compared to KEYTRUDA alone for patients with completely resected stage IIB, IIC, III or IV cutaneous melanoma who had not undergone prior treatment with systemic therapy. In accordance with the trial protocol, the study will continue in order to evaluate other key secondary endpoints, including overall survival (OS).

The safety profiles of intismeran and KEYTRUDA in this trial were consistent with those observed in previously reported studies for the combination, with no new safety signals observed.

These data will be presented at an upcoming international medical meeting and shared with regulatory authorities.

"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," said Professor Georgina Long, the study’s principal investigator and medical director of Melanoma Institute Australia, Chair of Melanoma Medical Oncology and Translational Research at the University of Sydney. "Intismeran in combination with pembrolizumab has the potential to establish a new treatment paradigm in the adjuvant melanoma setting, helping patients remain cancer-free for longer."

"By intervening earlier in the course of disease, when many cancers are considered most treatable, the goal of adjuvant therapy given after surgery is to increase the possibility of cure for more patients," said Dr. Dean Y. Li, president, Merck Research Laboratories. "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. Together with Moderna, we look forward to presenting data from INTerpath-001 at an international medical meeting and sharing with regulatory authorities."

"These Phase 3 findings represent a pivotal moment for the field of cancer research. For many years, the idea of creating an mRNA treatment designed specifically for an individual patient’s cancer was aspirational. We are now helping turn that vision into a reality," said Stéphane Bancel, CEO of Moderna. "Together with Merck, we have started to demonstrate the transformative potential of this technology to address critical unmet needs in the adjuvant melanoma setting. We are deeply grateful to the patients, investigators and study teams whose contributions make this progress possible."

Merck and Moderna are advancing the robust INTerpath clinical development program evaluating the safety and efficacy of intismeran in combination with KEYTRUDA and other anti-cancer therapies, and as a monotherapy. The INTerpath program currently consists of nine total Phase 2 and Phase 3 clinical trials across multiple tumor types and stages of disease, including melanoma, non-small cell lung cancer (NSCLC), bladder cancer and renal cell carcinoma. Additional clinical studies include the Phase 2b KEYNOTE-942/mRNA-4157-P201 trial in adjuvant melanoma and a Phase 1 study exploring adjuvant pancreatic ductal adenocarcinoma, perioperative gastric carcinoma and perioperative NSCLC.

Today’s Phase 3 readout builds on previously reported Phase 2b results for intismeran in combination with KEYTRUDA from the KEYNOTE-942/mRNA-4157-P201 trial, including the five-year follow-up data presented at the 2026 ASCO (Free ASCO Whitepaper) Annual Meeting, in which the combination demonstrated a 49% reduction in the risk of recurrence or death (HR=0.51; [95% CI, 0.294-0.887]) and a 59% reduction in the risk of distant metastasis or death (HR=0.411; [95% CI, 0.200-0.843]) compared to KEYTRUDA alone.

About INTerpath-001
INTerpath-001 is a randomized, double-blind, placebo- and active-comparator-controlled global Phase 3 trial (ClinicalTrials.gov, NCT05933577) evaluating the safety and efficacy of intismeran in combination with KEYTRUDA compared to KEYTRUDA alone in patients with high-risk (stage IIB-IV) resected cutaneous melanoma. The trial enrolled 1,137 patients who, following complete surgical resection, were randomized 2:1 to receive intismeran (1 mg every three weeks for up to nine doses) and KEYTRUDA (400 mg every six weeks up to nine cycles [for approximately one year]) versus KEYTRUDA alone for approximately one year until disease recurrence or unacceptable toxicity, or for a total treatment duration of up to approximately 56 weeks, whichever was sooner.

The primary endpoint is RFS, defined as the time from randomization to any disease recurrence (local, locoregional, regional or distant) as assessed by the investigator, or death due to any cause. Key secondary endpoints include DMFS, OS, safety, tolerability and quality of life.

About intismeran autogene
Intismeran autogene (intismeran; V940 or mRNA-4157) is a novel, potential first-in-class investigational messenger RNA (mRNA)-based individualized neoantigen therapy (INT) jointly developed by Merck and Moderna. Intismeran is designed and produced using a patient’s tumor sample to identify the unique mutational signature, or "fingerprint," of their cancer and generate an anti-tumor immune response. Each therapy consists of a synthetic mRNA coding for up to 34 neoantigens and is tailored to the unique biology of an individual patient’s tumor. Upon administration, the RNA-encoded neoantigen sequences are translated in the body and presented to the immune system, a key step in generating specific T-cell responses against cancer cells. Individualized neoantigen therapies are designed to train and activate an anti-tumor immune response based on the unique mutational signature of a patient’s tumor.

About melanoma
Melanoma, one of the deadliest forms of skin cancer, is characterized by the uncontrolled growth of pigment-producing cells. The rates of melanoma have been rising over the past few decades, with more than 330,000 new cases diagnosed worldwide in 2022. In the U.S., skin cancer is one of the most common types of cancer diagnosed, and melanoma accounts for a large majority of skin cancer deaths. It is estimated there will be about 112,000 new cases of melanoma diagnosed and over 8,500 deaths resulting from the disease in the U.S. in 2026 alone. Despite advances in treatment, patients with resected melanoma remain at risk of disease recurrence, which most often occurs within the first two years. The majority of recurrences are metastatic rather than localized, highlighting the ongoing need for treatment approaches that may help reduce the risk of recurrence and improve long-term outcomes.

(Press release, Merck & Co, AUG 19, 2026, View Source [SID1234670226])