Expert Reaction

EXPERT REACTION: Moderna announce results of Phase 3 trial of personalized mRNA cancer vaccine

Publicly released:
Australia; International; NSW
Photo by Louis Reed on Unsplash
Photo by Louis Reed on Unsplash

Merck and Moderna have announced the top line results of their Phase 3 trial of a personalised mRNA cancer vaccine. The companies say their trial showed statistically significant and clinically meaningful improvements in the amount of time that patients went without cancer signs or symptoms returning or spreading. They say the results show the potential to make a treatment designed specifically for an individual patient's cancer. Below, experts from Australia and the UK comment on the trial.

News release

From: Moderna

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

First and only combination regimen to demonstrate statistically significant and clinically meaningful improvements in RFS and DMFS compared to KEYTRUDA alone for these patients in the adjuvant melanoma setting

The Companies plan to present data at an upcoming international medical meeting and will engage with regulators on filing submissions for intismeran autogene in combination with KEYTRUDA

Intismeran autogene is an mRNA-based individualized neoantigen therapy (INT) designed specifically for each patient based on the unique set of mutations within their tumor to train and activate the immune system to recognize and fight cancer

RAHWAY, N.J. & CAMBRIDGE, Mass.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside of the United States and Canada, and Moderna, Inc. (NASDAQ: MRNA) today announced 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.

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 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.

About Merck’s research in melanoma
Merck is committed to delivering meaningful advances for patients with melanoma and to continuing research in skin cancers through a broad clinical development program across investigational and approved medicines. KEYTRUDA has been established as an important treatment option for the adjuvant treatment of patients with resected Stage IIB, IIC, or III melanoma based on results of KEYNOTE-054 and KEYNOTE-716. KEYTRUDA is also approved worldwide for the treatment of patients with unresectable or metastatic melanoma. Leveraging a decade of melanoma clinical trials, Merck continues to explore both innovative treatment approaches, including investigational individualized neoantigen therapies, and novel KEYTRUDA combinations with the goal of further improving long‑term outcomes for people living with melanoma.

About Merck’s early-stage cancer clinical program
Finding cancer at an earlier stage may give patients a greater chance of long-term survival. Many cancers are considered most treatable and potentially curable in their earliest stage of disease. Building on the strong understanding of the role of KEYTRUDA in later-stage cancers, Merck is evaluating our portfolio of medicines and pipeline candidates in earlier disease states, with more than 30 ongoing registrational studies across multiple types of cancer.

About KEYTRUDA® (pembrolizumab) injection for intravenous use, 100 mg
KEYTRUDA is an anti-programmed death receptor-1 (PD-1) therapy that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. KEYTRUDA is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD-L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells.

Merck has the industry’s largest immuno-oncology clinical research program. There are currently more than 2,800 trials studying KEYTRUDA across a wide variety of cancers and treatment settings. The KEYTRUDA clinical program seeks to understand the role of KEYTRUDA across cancers and the factors that may predict a patient’s likelihood of benefitting from treatment with KEYTRUDA, including exploring several different biomarkers.

Selected KEYTRUDA® (pembrolizumab) Indications in the U.S.
Melanoma

KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic melanoma.

KEYTRUDA is indicated for the adjuvant treatment of adult and pediatric (12 years and older) patients with Stage IIB, IIC, or III melanoma following complete resection.

Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Associate Professor Seth Cheetham is Deputy Director of the BASE mRNA Facility at The University of Queensland

"The positive outcome of Moderna and Merck’s Phase 3 trial of a personalised mRNA cancer vaccine in melanoma is a breakthrough for cancer treatment and personalised medicine. The mRNA vaccine is tailored for single individuals using the genetic blueprint of their individual tumour and helps immune cells better recognise and eradicate cancer cells.

The study enrolled patients with high-risk melanomas with the aim of preventing recurrence of their cancer after the tumour has been completely surgically removed. Yesterday the companies announced that trial had resulted in a "statistically significant and clinically meaningful improvement” in the rate of cancer recurrence and spread. While the full data, including the magnitude of the medicine’s impact, have not yet been released, they will be presented at upcoming medical conferences.

Phase 3 trials are critical as they demonstrate that a new medicine works in a large number of patients. The study involved 1137 patients split between the personalised vaccine + pembrolizumab (an immunotherapy that is the current standard of care) vs pembrolizumab alone (the control group) in a 2:1 ratio. These large studies are used by regulatory agencies to approve new medicines for widespread use in the community, and these results are likely to support the future approval of Moderna and Merck’s personalised cancer vaccine for melanoma within one to two years.  

The greatest challenge now will be to deliver this new type of medicine at the scale that it can reach patients throughout the community. While previous personalised medicines match patients to the right drug, this is the first to create an entirely new drug for each patient. The trial represents a landmark in personalised cancer medicine and is the start of a wave of new studies to bring this technology to patients with other diverse types of cancer."

Last updated:  20 Aug 2026 1:04pm
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Declared conflicts of interest I have received funding for conference attendance from Moderna in 2023. Moderna does not fund my research or influence any public statements.

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