Venetoclax Resistance in Acute Myeloid Leukemia

Abstract

Venetoclax is a BH3-mimetics agent interacting with the anti-apoptotic protein BCL2, facilitating cytochrome c release from mitochondria, subsequent caspases activation, and cell death. Venetoclax combined with azacitidine (VEN-AZA) has become a new standard treatment for AML patients unfit for intensive chemotherapy. In the phase III VIALE-A study, VEN-AZA showed a 65% overall response rate and 14.7 months overall survival in comparison with 22% and 8 months in the azacitidine monotherapy control arm. Despite these promising results, relapses and primary resistance to venetoclax are frequent and remain an unmet clinical need. Clinical and preclinical studies have been conducted to identify factors driving resistance. Among them, the most documented are molecular alterations including IDH, FLT3, TP53, and the newly described BAX mutations. Several non-genetic factors are also described such as metabolic plasticity, changes in anti-apoptotic protein expression, and dependencies, as well as monocytic differentiation status. Strategies to overcome venetoclax resistance are being developed in clinical trials, including triplet therapies with targeted agents targeting IDH, FLT3, as well as the recently developed menin inhibitors or immunotherapies such as antibody–drug conjugated or monoclonal antibodies. A better understanding of the molecular factors driving venetoclax resistance by single-cell analyses will help the discovery of new therapeutic strategies in the future.

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“…First-line therapy of eligible older patients continues to be chemotherapy with a combination of anthracycline and cytosine-arabinoside as a backbone; however, the combination of venetoclax and azacitidine or low-dose cytarabine, or low-dose cytarabine with glasdegib, could be the new standard of comparison for persons unfit for intensive therapy. Moreover, in selected studies, the survival of older patients with AML did not exceed 50% in 1 year, and primary resistance to venetoclax was frequent, remaining an unmet clinical need [4][5][6]. To improve venetoclax treatment outcomes, it was shown that a combination of venetoclax with other agents such as S63845, an MCL1 inhibitor, reduced the number of leukemic cells, indicating that MCL1 (S63845) and BCL-2 (venetoclax) inhibitors are synergistic and lead to T-ALL cell apoptosis [7].…”