42%: The Drop in Melanoma Risk From New mRNA Vaccine

Cancer treatments are moving away from one-size-fits-all approaches. That shift became clearer this week when major pharmaceutical partners announced new data on a personalized therapy for skin cancer.

Merck and Moderna reported that their mRNA vaccine reduced the risk of death or disease recurrence by 42 percent. This figure came from a late-stage trial comparing the vaccine against standard care. The standard treatment was Merck’s existing monoclonal antibody, Keytruda. Patients in the study had stage IIB to IV melanoma, which is the deadliest form of skin cancer. All participants had already undergone surgery to remove their tumors before joining the trial.

The trial involved 1,137 patients. They were randomly assigned in a two-to-one ratio. Those in the larger group received the personalized mRNA vaccine alongside the standard Keytruda treatment. The smaller group received only the standard treatment. The results indicate that adding the vaccine to the existing regimen offers a significant advantage for patients.

The companies first confirmed the vaccine’s success in August. However, they waited to release specific numbers until the data could be formally presented. That presentation was scheduled for the European Society of Medical Oncology conference in Madrid, Spain. The event began this week. An oncology news site reported the findings early, breaking the information embargo. Consequently, Merck and Moderna released the top-line results ahead of the original schedule. The full data has been accepted for publication in the New England Journal of Medicine.

Moderna CEO Stéphane Bancel emphasized the importance of the findings in a statement. He noted that the company has long believed mRNA technology could create treatments matched to individual tumors. “From the beginning, we believed mRNA technology could make it possible to develop cancer treatments uniquely matched to each patient’s tumor,” Bancel said. He described the results as a defining moment for that vision. The success also reinforces the view that mRNA can fundamentally change cancer treatment.

The companies are now working with regulatory authorities to seek approval for the vaccine. If approved, the therapy would represent a major new option for patients with advanced melanoma. The findings suggest that individualized medicines may become a broader standard in oncology.

The next step is the regulatory review process. The full data presentation at the Madrid conference will provide additional details for the medical community. For now, the 42 percent reduction in risk stands as the key metric for this new treatment approach.