MONDAY, June 1, 2026 (HealthDay News) -- For patients with resected high-risk melanoma, intismeran plus pembrolizumab offers clinically meaningful improvements in recurrence-free survival (RFS) and distant metastasis-free survival (DMFS) compared with pembrolizumab alone, according to a study published online June 1 in the Journal of Clinical Oncology to coincide with the annual meeting of the American Society of Clinical Oncology, held from May 29 to June 2 in Chicago.Adnan Khattak, M.D., Ph.D., from Edith Cowan University in Perth, Australia, and colleagues examined the efficacy and safety of intismeran plus pembrolizumab in resected high-risk melanoma after five years of follow-up. Adults with resected stage IIIB to IV cutaneous melanoma were randomly assigned to receive nine doses of intramuscular intismeran 1 mg plus 18 doses of intravenous pembrolizumab 200 mg or 18 doses of intravenous pembrolizumab 200 mg alone (107 and 50 patients, respectively).The researchers found that the RFS and DMFS hazard ratios were 0.510 (95 percent confidence interval, 0.294 to 0.887) and 0.411 (95 percent confidence interval, 0.200 to 0.843), respectively. Across most baseline subgroups analyzed, including biomarkers of immune checkpoint inhibitor response, RFS and DMFS results favored intismeran plus pembrolizumab. The overall survival hazard ratio was reduced, but did not reach statistical significance (hazard ratio, 0.471; 95 percent confidence interval, 0.165 to 1.345). The safety profile of intismeran was manageable, consistent with prior analyses. With intismeran plus pembrolizumab versus pembrolizumab, increased T-cell receptor clonality and novel clonotypes were seen."Our study offers strong evidence to melanoma patients that intismeran vaccine therapy, when used in combination with immunotherapy, can demonstrably reduce their risk of having their cancer return and improve clinical outcomes," senior author Janice M. Mehnert, M.D., from NYU Langone Health in New York City, said in a statement.The study was supported by Moderna and Merck, who are codeveloping intismeran.Abstract/Full Text (subscription or payment may be required)More Information.Sign up for our weekly HealthDay newsletter