On December 1st, 2022, the FDA approved the new molecular entity olutasidenib (Rezlidhia: Rigel Pharmaceuticals), a small-molecule inhibitor of isocitrate dehydrogenase-1 (IDH1), for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (R/R AML) with a susceptible IDH1 mutation as detected by an FDA-approved test. The efficacy of olutasidenib was established based on complete remission (CR) + CR with partial hematological recovery (CRh) rate, duration of CR + CRh, and conversion of transfusion dependence (TD) to transfusion independence (TI) in Study 2102-HEM-101. In the pivotal trial, 147 adult patients treated with 150mg twice daily (BID) of olutasidenib were evaluable for efficacy. With a median follow-up of 10.2 months, the CR/CRh rate was 35% (95% CI: 27-43%), with a median duration of response of 25.9 months (95% CI: 13.5 months, not reached [NR]). Of the 86 patients that were TD at baseline, 29 became TI (34%). The most common (≥20%) adverse reactions were nausea, fatigue, arthralgia, leukocytosis, dyspnea, pyrexia, rash, mucositis, diarrhea, and transaminitis. An assessment of long-term safety of olutasidenib is a condition of this approval.