Long GV, et al. - In this international, randomized, placebo-controlled, double-blind, parallel-group, phase 3 trial, patients with unresectable stage III or IV melanoma receiving epacadostat (an IDO1 selective inhibitor) plus pembrolizumab (a PD-1 inhibitor) vs placebo plus pembrolizumab were compared regarding progression-free survival and overall survival. Participants were aged 18 years or older, had unresectable stage III or IV melanoma previously untreated with PD-1 or PD-L1 checkpoint inhibitors, an ECOG performance status of 0 or 1, and had a known BRAF ^V600mutant status or had consented to BRAF ^V600 mutation testing during screening. After screening 928 patients, researchers randomized 706 patients to receive epacadostat plus pembrolizumab (n=354) or placebo plus pembrolizumab (n=352). As per outcomes, patients with unresectable or metastatic melanoma show no improvement in progression-free survival or overall survival using epacadostat 100 mg twice daily plus pembrolizumab vs placebo plus pembrolizumab.