IDH2 and acute myeloid leukemia: Enasidenib (AG-221) is an oral, selective inhibitor of mutant IDH2 that presented an acceptable tolerability profile, with 41% of 239 AML patients (113 in the dose-escalation phase and 126 in the four-arm expansion phase) reporting grade 3–4 treatment-emergent adverse events (hyperbilirubinemia, 12%; IDH differentiation syndrome, 6%; thrombocytopenia, 6%), in a first-in-human, phase 1/2 study [79].