Correlation of Venetoclax Plasma Concentrations With Toxicity of Hypometilating Agents and Venetoclax Combination for Acute Myeloid Leukemia Patients in Remission.

Venetoclax (VEN) is a potent and selective oral inhibitor of the BCL-2 gene and has shown anti-leukemic activity when used in combination with hypomethylating agents (HMA) in patients with Acute Myeloid Leukemia (AML), both newly diagnosed and in relapse or refractory (R/R) stages. A daily dose of 400 mg has shown the best results in terms of efficacy, toxicity, and low early mortality rates (DiNardo et al., Blood 2019). The HMA-VEN combination has been approved for the treatment of newly diagnosed AML patients who are not candidates for intensive therapy. However, although this treatment is considered low-intensity, it causes a non-negligible toxicity profile, especially hematological toxicity, even in patients who have already achieved remission. As a result, treatment often needs to be interrupted, and VEN dosage adjusted in subsequent cycles.

An analysis by Pratz et al. (Pratz et al., Am J Hematol 2022) following the publication of the pivotal trial reported grade IV cytopenias lasting at least 7 days in the cycles following remission in 161 (87%) patients in the VEN+Azacitidine arm. Furthermore, plasma concentrations of VEN were analyzed in patients who developed grade IV cytopenias for at least 7 days, and no correlation was found between VEN plasma levels and the number of observed cytopenias.

In the routine management of these patients, when hematologic toxicity occurs, the approach varies greatly from center to center and is based on the individual experience and assessment of the referring clinician. As a result, there is no standardized approach. Plasma concentrations of VEN are not routinely measured during treatment.

A better understanding of the factors determining the variable toxicity observed in patients in remission could optimize treatment to improve patient tolerability and allow for the regular administration of therapy, which is essential for maintaining leukemia remission status.