Enasidenib (Idhifa®) is an oral isocitrate dehydrogenase-2 (IDH2) inhibitor developed by Celgene Corporation under a global, exclusive license from Agios Pharmaceuticals. Enasidenib has been approved in the USA for the treatment of adults with relapsed or refractory acute myeloid leukaemia (AML) and an IDH2 mutation as detected by an FDA-approved test. It is at various stages of development in other countries for AML, myelodysplastic syndromes and solid tumours. This article summarizes the milestones in the development of enasidenib leading to this first global approval in the USA for the treatment of adults with relapsed or refractory IDH2-mutated AML.