The US Food and Drug Administration (FDA) has approved Rezlidhia™ (olutasidenib) for the treatment of adults with relapsed or refractory acute myeloid leukemia (AML) with a susceptible IDH1 mutation as detected by an FDA-approved test.

Olutasidenib is a small-molecule inhibitor of mutated IDH1. By inhibiting mutant IDH1, olutasidenib reduces 2-hydroxyglutarate levels and restores normal cellular differentiation of myeloid cells.

The FDA approval of olutasidenib was based on data from a single-arm, phase 1/2 trial ( Identifier: NCT0271957) that included 147 patients with relapsed or refractory AML with an IDH1 mutation confirmed through testing. Olutasidenib was administered orally at a dose of 150 mg twice daily until disease progression, development of unacceptable toxicity, or hematopoietic stem cell transplant.

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The primary endpoint of the study was a composite of a complete remission (CR) plus a complete remission with partial hematologic recovery (CRh). Efficacy was also measured by the duration of CR and CRh, as well as the rate of conversion from transfusion dependence to transfusion independence.

The CR/CRh rate was 35%, and the median duration of CR/CRh was 25.9 months. The median time to CR or CRh was 1.9 months.

Among the 86 patients who were dependent on red blood cell (RBC) and/or platelet transfusions at baseline, 34% became transfusion independent during any 56-day post-baseline period. Among the 61 patients who were not receiving RBC or platelet transfusions at baseline, 64% remained transfusion independent during any 56-day post-baseline period.

The most common adverse reactions reported with olutasidenib treatment were nausea, fatigue/malaise, arthralgia, constipation, dyspnea, pyrexia, rash, mucositis, diarrhea, and transaminitis. Laboratory abnormalities included increased aspartate aminotransferase, increased alanine aminotransferase, decreased potassium, decreased sodium, increased alkaline phosphatase, increased creatinine, increased lymphocytes, increased bilirubin, leukocytosis, increased uric acid, and increased lipase.

The prescribing information for olutasidenib contains a boxed warning regarding the risk of differentiation syndrome, which can be fatal.

Olutasidenib is supplied as 150 mg capsules. Patients should be selected for treatment based on the presence of IDH1 mutations in blood or bone marrow. The FDA has approved the Abbott RealTime IDH1 Assay to select patients for olutasidenib.


  1. Rigel announces US FDA approval of Rezlidhia™ (olutasidenib) for the treatment of adult patients with relapsed or refractory acute myeloid leukemia with a susceptible IDH1 mutation. News release. December 1, 2022.
  2. Rezlidhia. Package insert. Rigel Pharmaceuticals; 2022. Accessed December 2, 2022.

This article originally appeared on MPR