A Study of Epacadostat in Combination With Pembrolizumab and Chemotherapy in Participants With Advanced or Metastatic Solid Tumors (ECHO-207/KEYNOTE-723)

This was an open-label, nonrandomized, Phase 1/2 study designed to determine the safety, tolerability, and efficacy of epacadostat when given in combination with pembrolizumab and 7 different chemotherapy regimens described as Treatment Groups A through G below (see Study Drug and Background Therapies, Dose, and Mode of Administration). Phase 1 consisted of a 3 + 3 + 3 design intended to determine the MTD or PAD of epacadostat when given in combination with pembrolizumab and chemotherapy; efficacy was also explored. Phase 2 was designed to enroll efficacy expansion cohorts to further evaluate the safety, tolerability, and efficacy of epacadostat at the MTD or PAD (as selected in Phase 1) when given in combination with pembrolizumab and chemotherapy. Each efficacy expansion cohort was to enroll participants with 1 specific type of advanced or metastatic solid tumor. Additional cohorts (ie, the mandatory biopsy cohorts) were designed to evaluate changes in the tumor microenvironment in participants with any advanced or metastatic solid tumor who had progressed on previous therapy with a PD-1 or a PD-L1 inhibitor. No participants were enrolled in any Phase 2 efficacy expansion cohort, or in any Phase 2 mandatory biopsy cohort receiving Treatment A, B, F, or G. Phase 2 mandatory biopsy cohort participants received Treatments C, D, or E (ie, were included in Treatment Groups C, D, or E). Participants were assigned to a treatment group based on the chemotherapy regimen most appropriate for their tumor type.