Venetoclax, a selective B cell leukemia/lymphoma-2 (BCL2) inhibitor, has recently shown activity in relapsed or refractory (R/R) acute myeloid leukemia (AML). Effective biomarkers for identifying patients most likely to respond to venetoclax-based treatment are of clinical utility. In this study, we aimed to evaluate the efficacy and safety profiles of venetoclax-based therapy in a total 40 R/R AML patients and identify the potentially predictive factors for response. Overall response rate was 50%, including 9 (22.5%) complete response (CR) or CR with incomplete hematologic recovery of either neutrophil or platelet counts (CRi). Median time to best response was 1.4 months and the median overall survival (OS) was 6.6 months. Presence of intermediate-risk cytogenetics predicted better OS compared to unfavorable-risk cytogenetics. Patients harboring NPM1, RUNX1, or SRSF2 mutations seemed to have higher CR/CRi rates and median OS was significantly longer in RUNX1-mutated patients. On the contrary, patients with FLT3-ITD, TP53, or DNMT3A mutations did not reach any objective response and had worse OS. No laboratory or clinical tumor lysis syndrome was observed and the most common adverse events were prolonged cytopenias which resulted in 67.5% of febrile neutropenia. Patients with concurrent use of azole antifungals had similar incidence of cytopenias compared with those without azole antifungals. In summary, we demonstrate that venetoclax is an effective and well-tolerated salvage option for R/R AML patients. Survival benefits were particularly remarkable in patients with intermediate-risk cytogenetics or RUNX1 mutations. In contrast, TP53, NRAS, and DNMT3A mutations as well as FLT3-ITD conferred negative impact on survival. [ABSTRACT FROM AUTHOR]

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