Treatment
This study was originally designed to explore several epigenetic priming regimens, but azacitidine was the one tested due to the early study termination (discussed in the study conduct section).Treatment cycles were 21 days long. Dose escalation began with azacitidine 75 mg, pembrolizumab 200 mg IV Q3W, and oral epacadostat 100 mg BID. Five doses of azacitidine (75 or 100 mg per dose) were administered by intravenous infusion or subcutaneous injection over days 1–7 in cycles 1 and 2. Only the subcutaneous formulation of azacitidine was available to patients in the European Union. Dose reductions of azacitidine were permitted for the management of TEAEs, with a maximum of two dose reductions regardless of the initial starting dose. Epacadostat (100 or 300 mg) was administered orally BID without regard to food. Dose reductions of epacadostat were permitted for the management of TEAEs, with a maximum of two dose reductions regardless of the initial starting dose. Pembrolizumab 200 mg was administered as a 30-min, intravenous infusion every 3 weeks beginning on day 1 of cycle 1. Dose reductions of pembrolizumab were not permitted, but doses could be delayed to manage TEAEs.