(CNN) An experimental personalized mRNA vaccine in combination with the immunotherapy Keytruda reduced the risk of recurrence or death from melanoma in patients who had already had surgery, Moderna and Merck said Tuesday.
The randomized trial included 157 patients with stage 3 or stage 4 melanoma who had already had surgery. Some patients received nine doses of the experimental cancer vaccine made by Moderna and the immunotherapy made by Merck every three weeks for about a year, and some received only the immunotherapy. Treatment with the experimental vaccine in combination with the immunotherapy reduced the risk of cancer recurrence or death by 44% compared with the immunotherapy alone, the companies said.
The preliminary results of a Phase 2b trial were shared in a news release and have not been peer-reviewed or published. The companies said they will publish the full data in the future and share results at an upcoming conference.
The companies said they will initiate a Phase 3 study in melanoma patients next year, and will study additional tumor types.
"Today's results are highly encouraging for the field of cancer treatment. mRNA has been transformative for COVID-19, and now, for the first time ever, we have demonstrated the potential for mRNA to have an impact on outcomes in a randomized clinical trial in melanoma," Stéphane Bancel, chief executive officer for Moderna, said in a news release. Moderna is the maker of one of the mRNA Covid-19 vaccines used in the United States.
Moderna and Merck said serious treatment-related adverse events occurred in 14.4% of patients who received the vaccine and immunotherapy in the trial, and in 10% of patients who received only the immunotherapy. Keytruda has some known risks for serious side effects, the companies said.
Moderna's experimental cancer vaccine, mRNA-4157/V940, is designed to prime patients' immune system to generate a response to their specific tumors. Merck's Keytruda, which is already used in the treatment of melanoma, stimulates the immune system to attack tumors.
According to the American Cancer Society, melanoma accounts for about 1% of all skin cancers, but it causes a majority of skin cancer deaths. It estimates that in 2022, about 100,000 new melanomas will be diagnosed, and more than 7,600 people will die from melanoma.