Enasidenib, aslo known as AG-221 and CC-90007, is a potent and selective IDH2 inhibitor with potential anticancer activity (IDH2 = Isocitrate dehydrogenase 2). The mutations of IDH2 present in certain cancer cells result in a new ability of the enzyme to catalyze the NAPH-dependent reduction of α-ketoglutarate to R(-)-2-hydroxyglutarate (2HG). The production of 2HG is believed to contribute to the formation and progression of cancer. The inhibition of mutant IDH2 and its neoactivity is therefore a potential therapeutic treatment for cancer. Enasidenib is an orally available, selective, potent inhibitor of the mutated IDH2 protein, making it a highly targeted investigational medicine for the potential treatment of patients with cancers that harbor an IDH2 mutation. Enasidenib has received orphan drug and fast track designations from the U.S. FDA. Enasidenib mesylate is in phase II clinical trials for Solid tumours and phase III clinical trials for the treatment of acute myeloid leukaemia.