Merck, Moderna Report Positive Results for Their Melanoma Vaccine

Merck and Moderna reported the first positive Phase 3 result for an mRNA-based cancer vaccine, intismeran autogene combined with Keytruda, reducing melanoma recurrence in surgically treated patients. Meanwhile, Mexico's COFEPRIS has cut clinical trial approval timelines from 120 to 30 days and adopted regulatory reliance agreements to attract oncology research investment. 

Merck and Moderna announced positive Phase 3 results  for their personalized mRNA-based melanoma vaccine, marking the first successful late-stage clinical trial for an individualized cancer immunotherapy. The treatment, known as intismeran autogene, combined with Merck's immunotherapy Keytruda, significantly extended the time before cancer returned in patients whose high-risk melanoma had been surgically removed.

The randomized trial, called INTerpath-001, enrolled 1,137 patients with completely resected stage IIB-IV cutaneous melanoma, who received either intismeran autogene alongside Keytruda or Keytruda alone. The combination met its primary endpoint of recurrence-free survival, as well as a key secondary endpoint of distant metastasis-free survival, with results described as statistically significant and clinically meaningful. The companies did not disclose specific figures and reported no new safety signals compared with earlier studies of the combination. "We are now helping turn that vision into a reality," says Stéphane Bancel, CEO, Moderna, referring to the long-standing goal of building an mRNA treatment tailored to an individual patient's tumor.

Intismeran autogene is designed from the specific genetic mutations of each patient's tumor, training the immune system to recognize and attack cancer cells that display those mutations, a class of treatment known as a neoantigen vaccine. The approach builds on Phase 2 results presented earlier in the vaccine's development, which had already shown a reduction in recurrence risk when the combination was compared with Keytruda alone.   

Melanoma remains one of the deadliest forms of skin cancer, with more than 330,000 new cases diagnosed worldwide in 2022, according to World Health Organization (WHO). Merck and Moderna say they plan to present full trial data at an upcoming medical conference and to begin discussions with regulators regarding approval.

The announcement carries direct relevance for Mexico, where the health authorities are working to position the country as a more attractive destination for advanced clinical research. Mexico's Ministry of Health has moved to shorten the regulatory pathway for trials involving complex therapies such as personalized cancer vaccines. At the Scientific Conference 2026, the Federal Commission for the Protection Against Sanitary Risks (COFEPRIS) reported it had cut clinical trial approval timelines from 120 to 30 days, a shift Minister of Health David Kershenobich linked to efforts to increase Mexico's participation in international oncology studies. The reform followed a Regulatory Reliance agreement under which COFEPRIS recognizes prior evaluations from the US Food and Drug Administration (FDA), the European Medicines Agency (EMA), the UK Medicines and Healthcare products Regulatory Agency (MHRA), and Health Canada, reducing redundant local review for sponsors already working with those agencies.

The regulatory shift has already drawn a private-sector response relevant to companies weighing oncology investment in the country. Bayer announced in 2025 that it would triple its clinical study investment in Mexico, while AstraZeneca has expanded research partnerships with the Universidad Nacional Autónoma de México (UNAM), the Instituto Politécnico Nacional (IPN), and the Mexican Institute of Social Security (IMSS). Mexico's cancer burden underscores the stakes of that positioning: cancer diagnoses in the country are projected to nearly double by 2050, adding pressure on public institutions to secure earlier access to innovative treatments and on regulators to keep pace with global drug development timelines.

For Merck and Moderna, the melanoma results carry significant financial weight. Merck shares rose more than 10% in morning trading following the announcement, while Moderna's stock, which had lost most of its value since the peak of the COVID-19 pandemic, soared more than 120%. Analysts cited by the Boston Globe estimate an approved product could generate more than US$6 billion in annual sales in melanoma alone, with additional potential should the platform prove effective against lung, kidney, and bladder cancers, areas where the companies are already testing the same personalized approach.

The result also reinforces the broader commercial case for mRNA technology beyond infectious disease, following Moderna's earlier approval of the first mRNA-based flu vaccine. Mexico has separately signaled interest in local mRNA production capacity, part of a wider push toward what the Ministry of Health has termed pharmaceutical sovereignty, or reducing dependence on imported biologic inputs. Whether intismeran autogene or comparable neoantigen therapies eventually reach the Mexican market will depend on the pace of Merck and Moderna's regulatory submissions abroad and on how quickly COFEPRIS translates its shortened review timelines into approvals for complex, personalized biologics, a category the agency has identified as a priority under its evolving risk-based framework.