Venetoclax combination therapy in relapsed/refractory acute myeloid leukemia: A single institution experience

Venetoclax (VEN) is a selective BCL-2 inhibitor that has been shown to be effective when used in combination with hypomethylating agents (HMAs) or low-dose cytarabine (LDAC) for treatment-naïve, elderly acute myeloid leukemia (AML) patients unfit for intensive chemotherapy. Data on its use in the relapsed/refractory setting are limited. A retrospective analysis was performed among 14 patients with relapsed or refractory AML treated with VEN combination therapy at the University of California Los Angeles from 2018-2019. Eight patients received VEN in combination with azacitidine, 5 patients with decitabine, and 1 patient with LDAC. The majority (10 patients, 71.4%) had adverse cytogenetics. Three patients (21.4%) had undergone an allogeneic stem cell transplant prior to VEN therapy, and 5 patients (35.7%) had leukemia that failed HMA therapy prior. The objective response rate (ORR) was 35.7% (3 patients achieved complete remission with incomplete hematologic recovery and 2 patients achieved partial remission). Three patients (21.4%) were successfully transitioned to either allogeneic bone marrow transplant (2 patients) or donor lymphocyte infusion (1 patient). Seven patients (50.0%) developed a grade 3 or greater infection following VEN therapy, and 3 patients (21.4%) developed a grade 3 or greater intracranial hemorrhage. Three patients experienced early death within 30 days of therapy (2 from infection, 1 from bleeding). The median overall survival (OS) was 4.7 months, and the 1-year OS rate was 23.6% (95% CI 4.4-51.2) for the entire patient cohort. Overall, the response rate was not inferior to that with conventional salvage chemotherapy, but there were notable complications as a result of prolonged cytopenias.