FDA approves olutasidenib for relapsed or refractory acute myeloid leukemia with a susceptible IDH1 mutation
FDA approves olutasidenib (tradename: Rezlidhia) by Rigel Pharma for relapsed or refractory acute myeloid leukemia with a susceptible IDH1 mutation. Additionally, FDA approved the Abbott RealTime IDH1 Assay to select patients for olutasidenib as companion diagnostic.
REZLIDHIA is a potentially market-leading, oral, mutant isocitrate dehydrogenase-1 (mIDH1) inhibitor: binds to and inhibits mutated IDH1 enzymes.
Approval was based on Study 2102-HEM-101 (NCT02719574), an open-label, single-arm, multicenter clinical trial that included 147 adult patients with relapsed or refractory AML with an IDH1 mutation confirmed using the above assay. Olutasidenib was given orally,150 mg twice daily, until disease progression, unacceptable toxicity, or hematopoietic stem cell transplantation. The median treatment duration was 4.7 months (range: 0.1 - 26 months). Sixteen (11%) patients underwent hematopoietic stem cell transplantation following olutasidenib.
Efficacy was established on the rate of complete remission (CR) plus complete remission with partial hematologic recovery (CRh), the duration of CR+CRh, and the rate of conversion from transfusion dependence to independence. The CR+CRh rate was 35% (95% confidence interval [CI]: 27%, 43%), including 32% CR and 2.7% CRh. The median time to CR+CRh was 1.9 months (range: 0.9 - 5.6 months), and the median duration of CR+CRh was 25.9 months (95% CI: 13.5 months, not reached).
Among the 86 patients who were dependent on red blood cell (RBC) and/or platelet transfusions at baseline, 29 (34%) became independent of RBC and platelet transfusions during any 56-day post-baseline period. Of the 61 patients who were independent of both RBC and platelet transfusions at baseline, 39 (64%) remained transfusion independent during any 56-day post-baseline period.
The most common adverse reactions (≥20%) were nausea, fatigue/malaise, arthralgia, constipation, leukocytosis, dyspnea, fever, rash, mucositis, diarrhea, and transaminitis. The prescribing information contains a Boxed Warning alerting health care professionals and patients about the risk of differentiation syndrome which can be fatal.
The recommended olutasidenib dose is 150 mg taken orally twice daily on an empty stomach (at least 1 hour before or 2 hours after a meal) until disease progression or unacceptable toxicity. For patients without disease progression or unacceptable toxicity, treatment is recommended for a minimum of 6 months allowing for clinical response.