(HealthDay)—Pembrolizumab is associated with significantly longer recurrence-free survival than placebo as adjuvant therapy for high-risk stage III melanoma, according to a study published online April 15 in the New England Journal of Medicine. The research was published to coincide with the annual meeting of the American Association for Cancer Research, held from April 14 to 18 in Chicago.

Alexander M.M. Eggermont, M.D., Ph.D., from Gustave Roussy Cancer Campus Grand Paris, and colleagues randomized with completely resected stage III melanoma to receive 200 mg pembrolizumab (514 patients) or placebo (505 patients) intravenously every three weeks for 18 doses.

The researchers found that in the overall intention-to-treat population, pembrolizumab correlated with significantly longer recurrence-free survival than placebo at a median follow-up of 15 months (one-year rate of recurrence-free survival, 75.4 versus 61.0 percent; hazard ratio for recurrence or death, 0.57); the correlation was also seen in the subgroup of 853 patients with programmed death-1 ligand-positive tumors (one-year rate of recurrence-free survival, 77.1 versus 62.6 percent; hazard ratio, 0.54). Overall, 14.7 and 3.4 percent of patients in the pembrolizumab and placebo groups, respectively, had adverse events of grades 3 to 5 that were related to the trial regimen. One treatment-related death occurred in the pembrolizumab group.

"As for high-risk stage III melanoma, 200 mg of pembrolizumab administered every three weeks for up to one year resulted in significantly longer recurrence-free survival than , with no new toxic effects identified," the authors write.

One author disclosed financial ties to the pharmaceutical industry. The study was sponsored by Merck, the manufacturer of .