Effect of olutasidenib (FT-2102) on complete remissions in patients with relapsed/refractory (R/R) m<i>IDH1</i> acute myeloid leukemia (AML): Results from a planned interim analysis of a phase 2 clinical trial.
Authors: Stéphane De Botton, Karen W. L. Yee, Christian Recher, Andrew Wei, Pau Montesinos, David Taussig, Arnaud Pigneux, Thorsten Braun, Antonio Curti, Jordi Esteve, Carolyn Grove, Brian Andrew Jonas, Asim Khwaja, Ollivier Legrand, Pierre Peterlin, Olga Polyanskaya, Jennifer Sweeney, Hesham Mohamed, Jorge E. Cortes, Pierre Fenaux
Journal: Journal of Clinical Oncology (2021)

7006 Background: Olutasidenib, a potent, selective, oral, small molecule inhibitor of mutant IDH1 (m IDH1), has exhibited favorable tolerability and clinical activity in high-risk AML patients (pts) in a phase 1 trial (Watts, Blood 2019). Here, we present interim analysis results of a phase 2 trial (NCT02719574) in R/R m IDH1 AML pts receiving olutasidenib monotherapy 150 mg twice daily. Methods: The efficacy evaluable (EE) set comprised m IDH1 R132X pts whose first dose was ≥180 days before the data cut-off (18-JUN-20). The primary endpoint was CR+CRh (complete remission [CR] or CR with partial hematologic recovery [CRh] according to modified IWG 2003 criteria) rate. CRh was defined as bone marrow blasts &lt;5%, absolute neutrophil count &gt;0.5×10 9 /L, and platelet count &gt;50×10 9 /L. Overall response rate (ORR) comprised CR+CRh+CR with incomplete recovery (CRi) + morphologic leukemia-free state (MLFS) + partial response (PR). Duration of treatment (DOT), duration of response (DOR), and overall survival (OS) were estimated using Kaplan-Meier methodology. Results: This clinical trial met its pre-specified early enrollment-stopping criteria for efficacy. A total of 153 pts with R/R AML received olutasidenib; median DOT, 5.5 mo (95% CI: 4.4, 8.7). 43 pts (28%) remain on treatment and 110 (72%) discontinued, most commonly due to: disease progression, 31%; AEs, 14%; death, 10%; and transplant, 8%. For the EE set (123 pts), the median age was 71 y (range: 32‒87) with a median number of prior therapies of 2 (1‒7). The CR+CRh rate was 33% including 30% of pts in CR (Table). Median duration of CR+CRh was not reached (NR) and 13.8 mo in a sensitivity analysis when HSCT or relapse was deemed end of response. ORR was 46% and median duration of ORR was 11.7 mo. Of responders who were transfusion-dependent at baseline, 56-day platelet transfusion independence (TI) and RBC TI were gained by 100% and 83%, respectively, of pts who achieved CR+CRh, and by 56% and 50% who did not. Median OS was 10.5 mo (EE set). In CR+CRh responders, median OS was NR and the estimated 18-mo OS was 87%. TEAEs in ≥25% of pts were nausea, 38%; constipation, 25%; leukocytosis, 25%. Grade 3/4 all-causality TEAEs in &gt;10% of pts were febrile neutropenia, 20%; anemia, 19%; thrombocytopenia, 16%; neutropenia, 13%. Investigator-assessed IDH1 differentiation syndrome (any grade) was observed in 21 pts (14%); most cases resolved with treatment management; one case was fatal; 19 pts had concomitant leukocytosis. Conclusions: Olutasidenib was well tolerated and induced durable CR in a subset of high-risk R/R m IDH1 AML pts. TI was achieved in all response groups. Clinical benefit, per DOR and OS, extended beyond CR+CRh responders. Clinical trial information: NCT02719574. [Table: see text]