IDH2 and myeloproliferative disorder: In another more informative study of 8 patients with IDH2-mutated MPN-BP/AP (bone marrow blasts 10–80%) [37], 6 received enasidenib in the upfront and 2 relapsed/refractory setting; among the former, 5 patients received enasidenib monotherapy with one (20%) achieving CR (ELN criteria) (response duration 2 months to 3.3 years) and 2 (40%) PR or morphologic leukemia-free state; treatment-induced reduction in IDH2 mutant allele burden was documented in half of the responders and response duration was generally less than 2 years; grade-5 differentiation syndrome was observed in 2 patients [37].