Moderna and Merck's Personalized Cancer Vaccine Succeeds in Historic Late-Stage Melanoma Trial
A Phase 3 study involving more than 1,100 patients shows the customized mRNA treatment, given alongside an immunotherapy drug, significantly reduces the risk of skin cancer returning or spreading after surgery.
A personalized mRNA cancer vaccine developed by Moderna and Merck has successfully prevented high-risk skin cancer from returning in a large-scale, late-stage clinical trial, marking a major milestone in customized oncology.
The treatment, which is custom-built for each patient based on the unique genetic signature of their tumor, significantly reduced the risk of melanoma recurring or spreading to other organs when combined with an existing immunotherapy drug.
The Phase 3 trial, involving 1,137 patients who had previously undergone surgery to remove advanced melanoma, compared the combination therapy against the standard administration of Merck’s immunotherapy drug Keytruda alone.
Pre-planned interim results demonstrated that the customized vaccine provided statistically significant and clinically meaningful improvements in keeping patients cancer-free and preventing distant metastasis.
The outcome is the first successful late-stage trial for an individualized messenger RNA cancer treatment.
Unlike traditional vaccines that prevent infectious diseases, the therapy—officially named intismeran autogene—is administered to patients already diagnosed with cancer.
Scientists sequence a sample of the patient's surgically removed tumor to identify up to 34 unique genetic mutations.
Using the same mRNA technology that powered the COVID-19 vaccines, a bespoke treatment is manufactured to instruct the patient's immune system to recognize and attack those specific cancer cells.
Because the treatment relies on a tumor's specific mutational fingerprint, a vaccine created for one patient will not work for another, requiring strict manufacturing and handling protocols.
The breakthrough represents a shift toward highly personalized medicine, turning a long-held scientific aspiration into a proven clinical approach.
The success of the trial triggered an immediate financial reaction, with shares of Moderna jumping 17 percent and Merck rising 12 percent following the public release of the data.
The trial also reinforced earlier mid-stage results showing the combination therapy drastically lowered the risk of recurrence or death over a five-year period.
While researchers continue to monitor the trial participants to assess long-term overall survival, the companies are now preparing to present detailed data to the international medical community and submit the therapy to global regulators for approval.
Clinical trials are already expanding to test the personalized mRNA technology against other forms of the disease, including lung, bladder, and kidney cancers.