IDH1 and acute myeloid leukemia: Resistance to Ivosidenib (AG-120), an inhibitor of mIDH1, was also reported in the AML patients with the secondary mutation, S280F of IDH1. IDH1 S280F mutation was expected to result in a steric hindrance caused by substituted phenylalanine near the binding site of Ivosidenib and mIDH1 (Oltvai et al. 2021).