Randomized phase 2 trial of addition of personalized mRNA-vaccine to pembrolizumab after resection of high-risk melanoma

mRNA-4157 is a novel mRNA-based personalized cancer vaccine, which encodes up to 34 patient-specific tumor neoantigens. The multicenter phase 2 KEYNOTE-942 trial evaluated addition of mRNA-4157 to adjuvant pembrolizumab after complete resection of high-risk melanoma. At a median follow-up of 101 and 105 weeks in the two arms, respectively, recurrence or death was reported in 22.4% of the patients in the mRNA-4157 plus pembrolizumab group versus 40.0% of the patients in the pembrolizumab monotherapy group (HR 0.561; p=0.0266). The number of patients reporting grade 3 or higher TRAEs was generally similar between the arms (25% versus 18%). The authors conclude that a personalized neoantigen approach is potentially beneficial for cancer patients. A phase 3 study will be initiated in patients with melanoma.