Drugmakers Moderna and Merck announced Wednesday that an experimental personalized mRNA vaccine, called intismeran, helped keep high-risk melanoma from recurring or spreading when combined with the immunotherapy drug pembrolizumab (Keytruda). The late-stage trial enrolled 1,137 patients who had undergone surgery to remove their cancer.
Each vaccine was manufactured to match the unique genetic mutations of a patient's tumor, aiming to teach the immune system to recognize and attack any remaining cancer cells. Patients who received the vaccine plus pembrolizumab were less likely to experience recurrence or metastasis than those who received pembrolizumab alone.
The companies have not disclosed the magnitude of the risk reduction, and the findings have not yet been reviewed by independent scientists or published in a peer-reviewed journal. Moderna and Merck said they plan to present the complete data at an upcoming international medical meeting and submit it to regulatory authorities.
The approach uses messenger RNA technology, the same platform employed for COVID-19 vaccines, to produce a custom product for each patient rather than a single universal formulation. Researchers have pursued cancer vaccines for decades, but the ability to rapidly sequence a tumor and manufacture a tailored vaccine is a recent development.
Dr. Catherine Wu of Harvard Medical School and Dana-Farber Cancer Institute, whose lab demonstrated the feasibility of personalized cancer vaccines in small studies in 2017, described the results as gratifying. Dr. Elias Sayour, a pediatric oncologist at the University of Florida not involved in the trial, said the findings could herald a new wave of therapeutic cancer treatments.
Melanoma is among the deadliest skin cancers, with an estimated 112,000 new U.S. cases and more than 8,500 deaths expected this year. Even after surgery, the disease often returns within the first two years. Similar personalized mRNA vaccines are now being tested in lung, bladder, kidney, and pancreatic cancers.
Experts caution that the next challenge is extending the approach to tumors that may be more difficult to treat than melanoma. Manufacturing complexity, cost, and the time required to produce each individualized vaccine remain practical hurdles for broader adoption.
Personalized vaccine helped melanoma patients stay cancer-free longer, drugmakers say
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