Rezlidhia is an oral, small molecule inhibitor of mutated IDH1 that was approved by the FDA to treat patients with relapsed or refractory acute myeloid leukemia.
Rezlidhia (olutasidenib) is now available in the United States to treat adult patients with relapsed or refractory (R/R) acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation.
AML is a rapidly progressing cancer of the bone marrow and blood. The American Cancer Society estimates that about 20,940 new cases, most in adults, arose in 2021 in the United States alone.
Developed by Forma Therapeutics, Rezlidhia was approved by the FDA early in December 2022. It is an oral, small molecule inhibitor of mutated IDH1 designed to bind to and inhibit mIDH1 and restore normal cellular differentiation of myeloid cells. Rezlidhia will be marketed by Rigel Pharmaceuticals through an August 2022 marketing agreement with Forma, which is now part of Novo Nordisk.
The recommended dose of Rezlidhia is 150 mg taken orally twice daily. Based on the recommended dosage, the wholesale acquisition cost (WAC) in the United States is $32,200 per month. Rigel’s patient support program, ONECARE, helps patients navigate insurance and provides financial assistance.
In a phase 2 registrational study with 153 patients, Rezlidhia as a monotherapy demonstrated a robust composite complete remission rate and duration of response and was well-tolerated. The primary efficacy-evaluable population was comprised of 123 relapsed or refractory acute myeloid leukemia patients, who received Rezlidhia 150 mg twice daily at least six months prior to the interim analysis cutoff date of June 18, 2020. The primary endpoint was a composite of a complete remission plus a complete remission with partial hematological recovery, defined as less than 5% blasts in the bone marrow, no evidence of disease, and partial recovery of peripheral blood counts.
Results from the interim analysis of the trial demonstrated a 33% complete remission plus a complete remission with partial hematological recovery. Among those with complete remission plus a complete remission with partial hematological recovery, the estimated 18-month survival was 87%. A conservative sensitivity analysis indicated a median duration of 13.8 months.
Rezlidhia was well-tolerated, with adverse events being consistent with the late stage of disease and the heavily pre-treated population. A safety analysis for all 153 patients enrolled in the registrational phase 2 study found the most common grade 3/4 treatment-emergent adverse events were febrile neutropenia (20%), anemia (19%), thrombocytopenia (16%), and neutropenia (13%).
“Given the trial's compelling efficacy data in duration of response, the favorable tolerability profile, and the still limited treatment options of patients with mIDH1+ R/R AML, olutasidenib has the potential to be an important new treatment option for patients,” Jorge E. Cortes, M.D., director, Georgia Cancer Center and phase 2 trial investigator, said in a press release.