Enasidenib (formerly known as AG-221) that has gained FDA approval for IDH2 mutant AML patients, is a small molecule that selectively inhibits mIDH2 (IDH2R140Q and IDH2R172K) via binding to its allosteric site and prevents the conformation change requiring for the catalytic action and the R-2-hydroxyglutarate (R2HG) production. The gene discussed is IDH2; the disease is acute myeloid leukemia.