Impact of Venetoclax and Azacitidine in Treatment-Naïve Patients with Acute Myeloid Leukemia and IDH1/2 Mutations

PURPOSE: To evaluate efficacy and safety of venetoclax + azacitidine among treatment-naïve patients with IDH1/2-mutant (mut) acute myeloid leukemia (AML).

PATIENTS AND METHODS: Data were pooled from patients enrolled in a phase III study (NCT02993523) that compared patients treated with venetoclax + azacitidine or placebo + azacitidine and a prior phase Ib study (NCT02203773) where patients were treated with venetoclax + azacitidine. Enrolled patients were ineligible for intensive therapy due to age ≥75 years and/or comorbidities. Patients on venetoclax + azacitidine received venetoclax 400 mg orally (days 1-28) and azacitidine (75 mg/m2; days 1-7/28-day cycle).

RESULTS: In the biomarker-evaluable population, IDH1/2mut was detected in 81 (26%) and 28 (22%) patients in the venetoclax + azacitidine and azacitidine groups. Composite complete remission [CRc, complete remission (CR)+CR with incomplete hematologic recovery (CRi)] rates (venetoclax + azacitidine/azacitidine) among patients with IDH1/2mut were 79%/11%, median duration of remission (mDoR) was 29.5/9.5 months, and median overall survival (mOS) was 24.5/6.2 months. CRc rates among patients with IDH1/2 wild-type (WT) were 63%/31%, mDoR 17.5/10.3 months, and mOS 12.3/10.1 months. In patients with IDH1mut, CRc rates (venetoclax + azacitidine/azacitidine) were 66.7%/9.1% and mOS 15.2/2.2 months. In patients with IDH2mut, CRc rates were 86.0%/11.1% and mOS not reached (NR)/13.0 months. Patients with IDH1/2 WT AML treated with venetoclax + azacitidine with poor-risk cytogenetics had inferior outcomes compared with patients with IDH1/2mut, who had superior outcomes regardless of cytogenetic risk (mOS, IDH1/2mut: intermediate-risk, 24.5 months; poor-risk, NR; IDH1/2 WT: intermediate, 19.2 and poor, 7.4 months). There were no unexpected toxicities in the venetoclax + azacitidine group.

CONCLUSIONS: Patients with IDH1/2mut who received venetoclax + azacitidine had high response rates, durable remissions, and significant OS; cytogenetic risk did not mitigate the favorable outcomes seen from this regimen for IDH1/2mut. See related commentary by Perl and Vyas, p. 2719.