Study AG221-C-001 is a Phase 1/2, multicenter, open-label, dose-escalation, safety, PK/PD, and clinical activity evaluation of orally administered AG-221 in subjects with advanced hematologic malignancies that harbor an IDH2 mutation. The study includes a dose escalation phase to determine the maximum tolerated dose (MTD) and/or the recommended Phase 2 dose (RP2D) and an expansion phase to further evaluate the safety, tolerability and clinical activity of AG-221 in select populations.