Changes in 2-HG concentrations during enasidenib treatment. (A) Box plots of evaluable baseline-normalized serum 2-HG levels during the first 12 cycles of enasidenib treatment. Dotted lines indicate baseline 2-HG level. (B) Baseline-normalized median maximum reductions in 2-HG as a function of mutant-IDH2 allele and clinical response category. Baseline-normalized 2-HG for visit X = 2-HG at visit X divided by the average 2-HG at screening and at cycle 1 day 1. Outcomes are reported for the subgroup of patients with R/R AML who received enasidenib, 100 mg/d, and had longitudinal 2-HG data (n = 155).