Merck and Moderna Will Present Results From Landmark Phase 3 INTerpath-001 Trial for Intismeran Autogene Plus KEYTRUDA (pembrolizumab) at ESMO 2026 Presidential Symposium

Intismeran plus KEYTRUDA significantly reduced the risk of recurrence or death by 42% (HR=0.58 [95% CI, 0.45–0.75]; two-sided p<0.001) compared to KEYTRUDA alone for patients with completely resected stage IIB-IV melanoma

Benefit was greater after six months, following the intismeran immunization regimen, as intismeran plus KEYTRUDA reduced the risk of recurrence or death by 58% (piecewise HR=0.42 [95% CI, 0.30–0.58]) compared to KEYTRUDA alone in a pre-specified sensitivity analysis

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 detailed positive recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) results from the Phase 3 INTerpath-001 trial evaluating 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, as adjuvant treatment for patients with completely resected stage IIB-IV melanoma. These late-breaking results will be presented for the first time during Presidential Symposium I at the European Society for Medical Oncology (ESMO) Congress 2026 (Presentation #LBA1), were selected for an official ESMO Press Briefing and have been accepted for publication in The New England Journal of Medicine.

At the primary pre-specified analysis (intention-to-treat), after a median follow-up of 24.6 months, intismeran in combination with KEYTRUDA significantly reduced the risk of recurrence or death by 42% (HR=0.58 [95% CI, 0.45–0.75]; two-sided p<0.001). Intismeran plus KEYTRUDA also significantly reduced the risk of distant metastasis or death by 38% (HR=0.62 [95% CI, 0.45–0.85]; two-sided p=0.002) compared to KEYTRUDA alone. The improvements observed in RFS and DMFS were generally consistent across pre-specified patient subgroups. Overall survival (OS) data are not yet mature, but a favorable trend in OS with intismeran plus KEYTRUDA has been observed. The study remains ongoing to further evaluate OS and other key endpoints. The safety profile of intismeran plus KEYTRUDA was generally consistent with previously reported studies of the combination, and no new safety signals were observed. Based on these data, we are engaging with regulatory authorities.

The efficacy of the intismeran immunization plus KEYTRUDA in the first six months was comparable with KEYTRUDA alone for risk of recurrence or death (HR=0.99 [95% CI, 0.66–1.49]) and risk of distant metastasis or death (HR=1.01 [95% CI, 0.58–1.79]). At six months, following the intismeran immunization regimen, a pre-specified sensitivity analysis of the primary endpoint showed the addition of intismeran plus KEYTRUDA reduced the risk of recurrence or death by 58% (HR=0.42 [95% CI, 0.30–0.58]) and reduced the risk of distant metastasis or death by half (HR=0.50 [95% CI, 0.34–0.73]) compared to KEYTRUDA alone.

In a pre-specified sensitivity analysis of the modified intent-to-treat (mITT) population, which excluded participants who did not receive at least one dose of intismeran or placebo as planned, intismeran plus KEYTRUDA reduced the risk of recurrence or death by 49% (HR=0.51 [95% CI, 0.39–0.67]) and the risk of distant metastasis or death by 45% (HR=0.55 [95% CI, 0.40–0.77]) compared to KEYTRUDA alone.

“The transformative INTerpath-001 results have the potential to make a foundational shift in how we treat patients with earlier-stage melanoma in the adjuvant setting,” 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. “For decades, cancer treatment has largely been defined by where a tumor originates in the body. The INTerpath-001 findings support a fundamentally new and individualized approach to treating resected melanoma in the adjuvant setting, one that tailors treatment to the unique mutational signature of a patient’s tumor to enhance an anti-tumor immune response. While these results are in patients with completely resected stage IIB-IV melanoma, they provide valuable insights and will help inform our understanding of intismeran as clinical research continues into other tumor types and across settings.”

“INTerpath-001 is the first Phase 3 study to demonstrate a clinically meaningful improvement in RFS and DMFS over standard-of-care KEYTRUDA in patients with resected melanoma, setting a new benchmark in the adjuvant setting and representing one of the most significant advances in melanoma treatment since the advent of immunotherapy,” said Dr. Dean Y. Li, president, Merck Research Laboratories. “These results, building on the body of evidence from the Phase 2b study, strengthen our confidence in the curative potential of intismeran autogene when given in combination with KEYTRUDA. Importantly, these data suggest that, by intervening earlier, this approach may offer a tangible opportunity to change the trajectory of a patient's cancer.”

“From the beginning, we believed mRNA technology could make it possible to develop cancer treatments uniquely matched to each patient’s tumor. The INTerpath-001 results mark a defining moment for that vision and show what’s possible when we rethink how medicines are made,” said Stéphane Bancel, Chief Executive Officer of Moderna. “These results reinforce our conviction that mRNA has the potential to fundamentally change how we treat cancer.”

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 three ongoing Phase 3 trials in non-small cell lung cancer (NSCLC). 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 (Abstract #3151P), perioperative gastric carcinoma and perioperative NSCLC.

The results from INTerpath-001 build 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.

Study design and additional data from 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]) compared to placebo plus KEYTRUDA 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.

In the ITT population, the two-year RFS rate was 82.2% (95% CI, 79.3%–84.8%) for intismeran plus KEYTRUDA compared to 70.0% (95% CI, 65.0%–74.5%) for KEYTRUDA alone. Median RFS was not reached (NR) (95% CI, not estimable [NE]–NE) for either arm. Additionally, the two-year DMFS rate was 88.5% (95% CI, 86.0%–90.6%) for intismeran plus KEYTRUDA compared to 80.2% (95% CI, 75.6%–84.0%) for KEYTRUDA alone. Median DMFS was NR (95% CI, NE–NE) for either arm.

Treatment-related adverse events (TRAEs) occurred in 95.8% (723 of 755 patients) receiving intismeran plus KEYTRUDA and 90.0% (342 of 380 patients) receiving KEYTRUDA alone. Grade 3–5 TRAEs occurred in 14.2% (n=107) versus 13.4% (n=51) of patients, respectively. The most common adverse events in the intismeran plus KEYTRUDA arm were pyrexia (52.2%), injection site pain (51.0%) and fatigue (38.5%).

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 of their cancer and generate an anti-tumor immune response. Information derived from the patient’s tumor and normal DNA is used to create an individualized treatment design, or “blueprint,” informed by selected neoantigens unique to that patient’s cancer. Each therapy consists of a synthetic mRNA coding for up to 34 neoantigens. 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 338,000 new cases diagnosed worldwide in 2024. 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 following surgery. Disease recurrence can be metastatic as well as localized, with more than half of patients who experience recurrence developing one or more distant metastases. Distant metastases can spread to critical organs, including the lung, liver and brain, and are associated with substantially worse outcomes, underscoring the continued need for treatment approaches that can help reduce the risk of recurrence and the risk of local and distant metastasis.

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 Indications in the U.S. for KEYTRUDA^® (pembrolizumab)

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.

See additional selected KEYTRUDA indications in the U.S. after the Selected Important Safety Information.

Selected Safety Information for KEYTRUDA

Severe and Fatal Immune-Mediated Adverse Reactions

KEYTRUDA is a monoclonal antibody that belongs to a class of drugs that bind to either the programmed death receptor-1 (PD-1) or the programmed death ligand 1 (PD-L1), blocking the PD-1/PD-L1 pathway, thereby removing inhibition of the immune response, potentially breaking peripheral tolerance and inducing immune-mediated adverse reactions. Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue, can affect more than one body system simultaneously, and can occur at any time after starting treatment or after discontinuation of treatment. Important immune-mediated adverse reactions listed here may not include all possible severe and fatal immune-mediated adverse reactions.

Monitor patients closely for symptoms and signs that may be clinical manifestations of underlying immune-mediated adverse reactions. Early identification and management are essential to ensure safe use of anti–PD-1/PD-L1 treatments. Evaluate liver enzymes, creatinine, and thyroid function at baseline and periodically during treatment. For patients with TNBC treated with KEYTRUDA in the neoadjuvant setting, monitor blood cortisol at baseline, prior to surgery, and as clinically indicated. In cases of suspected immune-mediated adverse reactions, initiate appropriate workup to exclude alternative etiologies, including infection. Institute medical management promptly, including specialty consultation as appropriate.

Withhold or permanently discontinue KEYTRUDA depending on severity of the immune-mediated adverse reaction. In general, if KEYTRUDA requires interruption or discontinuation, administer systemic corticosteroid therapy (1 to 2 mg/kg/day prednisone or equivalent) until improvement to Grade 1 or less. Upon improvement to Grade 1 or less, initiate corticosteroid taper and continue to taper over at least 1 month. Consider administration of other systemic immunosuppressants in patients whose adverse reactions are not controlled with corticosteroid therapy.

Immune-Mediated Pneumonitis

KEYTRUDA can cause immune-mediated pneumonitis. The incidence is higher in patients who have received prior thoracic radiation. Immune-mediated pneumonitis occurred in 3.4% (94/2799) of patients receiving KEYTRUDA, including fatal (0.1%), Grade 4 (0.3%), Grade 3 (0.9%), and Grade 2 (1.3%) reactions. Systemic corticosteroids were required in 67% (63/94) of patients. Pneumonitis led to permanent discontinuation of KEYTRUDA in 1.3% (36) and withholding in 0.9% (26) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 23% had recurrence. Pneumonitis resolved in 59% of the 94 patients.

Pneumonitis occurred in 8% (31/389) of adult patients with cHL receiving KEYTRUDA as a single agent, including Grades 3-4 in 2.3% of patients. Patients received high-dose corticosteroids for a median duration of 10 days (range: 2 days to 53 months). Pneumonitis rates were similar in patients with and without prior thoracic radiation. Pneumonitis led to discontinuation of KEYTRUDA in 5.4% (21) of patients. Of the patients who developed pneumonitis, 42% interrupted KEYTRUDA, 68% discontinued KEYTRUDA, and 77% had resolution.

Pneumonitis occurred in 7% (41/580) of adult patients with resected NSCLC who received KEYTRUDA as a single agent for adjuvant treatment of NSCLC, including fatal (0.2%), Grade 4 (0.3%), and Grade 3 (1%) adverse reactions. Patients received high-dose corticosteroids for a median duration of 10 days (range: 1 day to 2.3 months). Pneumonitis led to discontinuation of KEYTRUDA in 26 (4.5%) of patients. Of the patients who developed pneumonitis, 54% interrupted KEYTRUDA, 63% discontinued KEYTRUDA, and 71% had resolution.

Immune-Mediated Colitis

KEYTRUDA can cause immune-mediated colitis, which may present with diarrhea. Cytomegalovirus infection/reactivation has been reported in patients with corticosteroid-refractory immune-mediated colitis. In cases of corticosteroid-refractory colitis, consider repeating infectious workup to exclude alternative etiologies. Immune-mediated colitis occurred in 1.7% (48/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (1.1%), and Grade 2 (0.4%) reactions. Systemic corticosteroids were required in 69% (33/48); additional immunosuppressant therapy was required in 4.2% of patients. Colitis led to permanent discontinuation of KEYTRUDA in 0.5% (15) and withholding in 0.5% (13) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 23% had recurrence. Colitis resolved in 85% of the 48 patients.

Hepatotoxicity and Immune-Mediated Hepatitis

KEYTRUDA as a Single Agent

KEYTRUDA can cause immune-mediated hepatitis. Immune-mediated hepatitis occurred in 0.7% (19/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.4%), and Grade 2 (0.1%) reactions. Systemic corticosteroids were required in 68% (13/19) of patients; additional immunosuppressant therapy was required in 11% of patients. Hepatitis led to permanent discontinuation of KEYTRUDA in 0.2% (6) and withholding in 0.3% (9) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, none had recurrence. Hepatitis resolved in 79% of the 19 patients.

KEYTRUDA With Axitinib

KEYTRUDA in combination with axitinib can cause hepatic toxicity. Monitor liver enzymes before initiation of and periodically throughout treatment. Consider monitoring more frequently as compared to when the drugs are administered as single agents. For elevated liver enzymes, interrupt KEYTRUDA and axitinib, and consider administering corticosteroids as needed. With the combination of KEYTRUDA and axitinib, Grades 3 and 4 increased alanine aminotransferase (ALT) (20%) and increased aspartate aminotransferase (AST) (13%) were seen at a higher frequency compared to KEYTRUDA alone. Fifty-nine percent of the patients with increased ALT received systemic corticosteroids. In patients with ALT ≥3 times upper limit of normal (ULN) (Grades 2-4, n=116), ALT resolved to Grades 0-1 in 94%. Among the 92 patients who were rechallenged with either KEYTRUDA (n=3) or axitinib (n=34) administered as a single agent or with both (n=55), recurrence of ALT ≥3 times ULN was observed in 1 patient receiving KEYTRUDA, 16 patients receiving axitinib, and 24 patients receiving both. All patients with a recurrence of ALT ≥3 ULN subsequently recovered from the event.

Immune-Mediated Endocrinopathies

Adrenal Insufficiency

KEYTRUDA can cause primary or secondary adrenal insufficiency. For Grade 2 or higher, initiate symptomatic treatment, including hormone replacement as clinically indicated. Withhold KEYTRUDA depending on severity. Adrenal insufficiency occurred in 0.8% (22/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.3%), and Grade 2 (0.3%) reactions. Systemic corticosteroids were required in 77% (17/22) of patients; of these, the majority remained on systemic corticosteroids. Adrenal insufficiency led to permanent discontinuation of KEYTRUDA in <0.1% (1) and withholding in 0.3% (8) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement.

Hypophysitis

KEYTRUDA can cause immune-mediated hypophysitis. Hypophysitis can present with acute symptoms associated with mass effect such as headache, photophobia, or visual field defects. Hypophysitis can cause hypopituitarism. Initiate hormone replacement as indicated. Withhold or permanently discontinue KEYTRUDA depending on severity. Hypophysitis occurred in 0.6% (17/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.3%), and Grade 2 (0.2%) reactions. Systemic corticosteroids were required in 94% (16/17) of patients; of these, the majority remained on systemic corticosteroids. Hypophysitis led to permanent discontinuation of KEYTRUDA in 0.1% (4) and withholding in 0.3% (7) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement.

Thyroid Disorders

KEYTRUDA can cause immune-mediated thyroid disorders. Thyroiditis can present with or without endocrinopathy. Hypothyroidism can follow hyperthyroidism. Initiate hormone replacement for hypothyroidism or institute medical management of hyperthyroidism as clinically indicated. Withhold or permanently discontinue KEYTRUDA depending on severity. Thyroiditis occurred in 0.6% (16/2799) of patients receiving KEYTRUDA, including Grade 2 (0.3%). None discontinued, but KEYTRUDA was withheld in <0.1% (1) of patients.

Hyperthyroidism occurred in 3.4% (96/2799) of patients receiving KEYTRUDA, including Grade 3 (0.1%) and Grade 2 (0.8%). It led to permanent discontinuation of KEYTRUDA in <0.1% (2) and withholding in 0.3% (7) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement. Hypothyroidism occurred in 8% (237/2799) of patients receiving KEYTRUDA, including Grade 3 (0.1%) and Grade 2 (6.2%). It led to permanent discontinuation of KEYTRUDA in <0.1% (1) and withholding in 0.5% (14) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement. The majority of patients with hypothyroidism required long-term thyroid hormone replacement. The incidence of new or worsening hypothyroidism was higher in 1185 patients with HNSCC, occurring in 16% of patients receiving KEYTRUDA as a single agent or in combination with platinum and FU, including Grade 3 (0.3%) hypothyroidism. The incidence of new or worsening hypothyroidism was higher in 389 adult patients with cHL (17%) receiving KEYTRUDA as a single agent, including Grade 1 (6.

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