Melanoma Vaccine: NEJM Reports 82% Recurrence-Free at 2 Years

Key takeaways

• The New England Journal of Medicine published the full Phase 3 INTerpath-001 report on November 11, 2026.

• At two years, 82.2% of patients given the experimental personalized vaccine plus pembrolizumab were alive without melanoma recurrence, compared with 70.0% in the pembrolizumab-plus-placebo group.

• The treatment remains investigational. The report does not establish an overall-survival benefit or make the vaccine available as standard care.

The peer-reviewed report covers 1,137 people with high-risk skin melanoma that had been completely removed by surgery. It found better two-year recurrence-free and distant-metastasis-free outcomes when the individualized mRNA therapy intismeran was added to pembrolizumab, sold as Keytruda. The results add full journal detail to findings first announced by Merck and Moderna in October; they are not an FDA approval.

What happened in the trial?

The study, called INTerpath-001, was published in the New England Journal of Medicine on November 11, 2026. It was a Phase 3, randomized, double-blind trial involving 1,137 people with completely resected stage IIB to IV cutaneous melanoma. Participants were assigned in a 2-to-1 ratio: 757 received intismeran plus pembrolizumab, while 380 received a placebo plus pembrolizumab.

Pembrolizumab was given to both groups. The experimental group also received intismeran, an individualized neoantigen therapy designed to prompt T cells to recognize features specific to a patient's tumor. The study tested the combination as adjuvant treatment — care given after surgery to reduce the chance that cancer returns.

After a median follow-up of 24.6 months, the estimated two-year recurrence-free survival rate was 82.2% in the intismeran group and 70.0% in the placebo group. Recurrence-free survival measures the period in which a patient remains alive without the cancer returning.

The secondary result also favored the combination: two-year distant-metastasis-free survival was 88.5%, compared with 80.2%. That measure tracks survival without melanoma spreading to a distant part of the body.

The paper includes an important timing detail. In a prespecified analysis split at six months, the relative hazard of recurrence or death was similar between groups during the first six months (hazard ratio 0.99). After six months, the hazard ratio was 0.42. A hazard ratio compares the rate of an event between groups over time; it is not a percentage-point change or a prediction for any one patient.

The study was funded by Merck Sharp & Dohme and Moderna. The companies had announced the main trial findings on October 22, 2026, and said the results had been accepted for publication. The November 11 paper is the full peer-reviewed report. Johns Hopkins Medicine, whose cancer center participated in the multicenter trial, also discussed the findings and the wider research behind therapeutic cancer vaccines in a November 11 report.

Sources: the Phase 3 paper in the New England Journal of Medicine, Johns Hopkins Medicine's November 11 overview, and Merck's October 22 trial announcement.

Why the results matter

Analysis: Melanoma can return after surgery, including in people whose visible tumor has been removed. The trial tests a way to make follow-up treatment more specific: use information from an individual's tumor to design an immune-targeting therapy, then pair it with a checkpoint inhibitor that helps immune cells remain active.

The difference in two-year recurrence-free survival is substantial enough to make the approach worth watching. But the study compares two treatment regimens in a defined group of patients. It does not show that a cancer vaccine can prevent melanoma in healthy people, treat every stage of the disease, or replace surgery and established therapies.

The results also do not yet answer whether the combination helps patients live longer overall. Merck and Moderna said in their October 22 announcement that overall-survival data were not mature and follow-up would continue. The peer-reviewed paper reports recurrence and distant-spread outcomes, not a confirmed overall-survival advantage.

What this means for patients now

There is no new vaccine for the general public to book or buy. Intismeran is an individualized treatment being studied in people with selected stages of melanoma after complete surgical removal. It is not a preventive vaccine like those used to prevent infectious diseases.

For someone being treated for melanoma, the practical step is to discuss the current treatment plan with an oncology team. Ask whether the person's stage, surgery results, prior treatment and health history affect the options available. Do not postpone care or change a prescribed treatment because of a news report.

The pivotal INTerpath-001 study is listed on ClinicalTrials.gov as active but not recruiting. That status means the trial is continuing but is not currently enrolling new participants. Merck and Moderna said they were engaging with regulators; the journal publication itself does not authorize routine use.

For more context on how different vaccine studies measure outcomes, see Big Zero's report on flu vaccine effectiveness across 18 seasons. For a separate example of the distinction between clinical evidence and a regulatory decision, read our coverage of the FDA approval of Sunharbo for recurrent-stroke risk reduction.

What remains unknown and what to watch next

The main unanswered question is overall survival: whether the recurrence and metastasis results eventually translate into people living longer. Researchers also need longer follow-up to understand how durable the benefit is beyond the study's median follow-up of 24.6 months.

The safety results deserve attention as well. Grade 3 or higher adverse events were reported in 23.6% of patients in the intismeran group and 20.3% in the placebo group. Eight patients in the intismeran-plus-pembrolizumab group died from an adverse event; the paper says five of those deaths occurred before intismeran was administered. Those figures should be read as trial safety data, not as proof that the vaccine caused those deaths.

The next milestones are continued follow-up, any regulatory submissions or decisions, and results from other studies testing individualized cancer vaccines in different settings. A positive result in resected melanoma cannot automatically be applied to other cancers.

FAQ

Is this a vaccine that prevents melanoma?

No. Intismeran is a therapeutic, individualized treatment being tested after surgery in people with high-risk melanoma. It is designed around features of a patient's tumor, rather than given to healthy people to prevent the disease.

Does the 82.2% result mean the vaccine cured 82% of patients?

No. It is the estimated two-year recurrence-free survival rate for the group that received intismeran with pembrolizumab. It does not mean every person in that group was cured, and it cannot predict an individual patient's outcome.

Is intismeran approved by the FDA?

The trial paper describes it as an investigational therapy. Merck and Moderna said they were engaging with regulators, while the pivotal study remains listed as active but not recruiting; the publication is not an FDA approval.

Did the vaccine replace Keytruda in the study?

No. Both groups received pembrolizumab, the medicine marketed as Keytruda. The comparison was between pembrolizumab plus intismeran and pembrolizumab plus placebo.

Should a patient change treatment after reading these results?

No treatment decision should be made from a news article alone. Patients should review the findings and their own options with their oncologist, and should not stop or delay prescribed care without medical guidance.

Bottom line

The November 11 paper provides peer-reviewed evidence that adding a personalized mRNA therapy to pembrolizumab improved two-year recurrence-free and distant-metastasis-free outcomes in a specific group of people with surgically removed high-risk melanoma. It is a meaningful research advance, not a newly available vaccine: long-term survival and regulatory decisions remain unresolved.