A combination of an experimental mRNA cancer vaccine and immunotherapy reduced the risk of death or recurrence in melanoma patients by 42% compared to standard treatment, according to data from a Phase 3 clinical trial. The findings, reported by Agerpres, indicate that the vaccine—known as Intismeran—when paired with Merck’s Keytruda, also decreased the risk of cancer spreading by 38% over a two-year period.
Combination Therapy Keeps More Melanoma Patients Cancer-Free
The study involved more than 1,100 participants who had undergone surgery to remove melanoma lesions. Researchers compared patients receiving the combination therapy against those treated with Keytruda alone. According to data, 82.2% of patients in the vaccine-plus-immunotherapy group remained cancer-free after two years, compared to 70% in the group receiving only the immunotherapy.
Dr. Hussein Tawbi, a melanoma expert and investigator at the University of Texas MD Anderson Cancer Center, characterized these results as statistically significant. "It is not a matter of chance," he stated, as reported by Agerpres.
Mechanism of the Combined Therapy
The treatment protocol uses two distinct mechanisms to address cancer cells. Keytruda works by blocking the "brakes" that cancer cells use to evade detection by the immune system. Simultaneously, the mRNA vaccine is customized based on the unique mutations found in an individual patient’s tumor. It instructs the body to produce copies of those specific mutations, training the immune system to identify and destroy the malignant cells. Moderna CEO Stephane Bancel described this process as a new chapter in oncology, noting the ability to create "new T cells that are specific to each patient’s tumor," according to Agerpres.
Moderna and Merck Shares Fall After Trial Results
Following the disclosure of the trial results on an oncology website, Moderna’s stock price closed down by 17.57%, while Merck shares fell approximately 1.8%, Agerpres noted. Biziday reported that the market reaction reflected high expectations rather than a failure of the therapy. Analysts at UBS described the data as "solid," while some observers, such as Tyler Van Buren of TD Cowen, noted that while the results were favorable, they did not fully align with the most optimistic market projections.
Companies Seek Regulatory Approval for 2027 Launch
Moderna and Merck are preparing to seek regulatory approval in the United States, with an estimated market launch for the vaccine in 2027, according to Agerpres. The combination therapy is currently being tested for efficacy in other conditions, including renal, bladder, and lung cancers. While the current trial results focus on melanoma, Bancel indicated that the team plans to evaluate the vaccine’s performance wherever Keytruda is already authorized, a list that currently includes 19 different types of cancer.
Is This Vaccine Available for Other Types of Cancer?
Is this vaccine available for other types of cancer?
The combination is currently in clinical trials for several other cancers, including renal, bladder, and lung cancer. However, researchers emphasize that success in melanoma does not guarantee the same results for all cancer types, and further studies are required.
How does the vaccine differ from traditional treatments?
Unlike traditional vaccines that prevent infection, this is a personalized treatment designed for patients who have already been diagnosed. It is manufactured specifically for each patient based on the genetic mutations identified in their surgically removed tumor.
When will the full study results be available?
The complete Phase 3 data, covering the first two years of patient follow-up, are scheduled to be presented Saturday at the European Society for Medical Oncology congress in Madrid.
The results of this study underscore the potential of mRNA technology in personalized medicine, a field that also saw recent progress in ovarian cancer research published in Nature Medicine on October 14, 2026, which demonstrated that a similar personalized vaccine approach could successfully trigger an immune response in a small group of patients.
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