Mechanisms of resistance to venetoclax in hematologic malignancies.

Venetoclax, a BH3 mimetic, is a novel targeted anti-cancer drug with a unique mechanism of action leading to the execution of apoptosis through inhibition of the Bcl-2 protein. The development of venetoclax has revolutionized the treatment paradigm of several hematologic malignancies, including treatment-naïve and relapsed or refractory chronic lymphocytic leukemia (CLL) as well as acute myeloid leukemia (AML) in unfit patients. However, despite the high effectiveness of venetoclax in these diseases, some patients, as in the case with other targeted therapies, develop primary or secondary resistance to the drug. Various mechanisms contributing to the resistance to venetoclax have been elucidated, including selection of mutations in the BCL-2 binding groove which decrease affinity to venetoclax, or compensatory overexpression of anti-apoptotic proteins such as MCL-1. Moreover, alterations in cell metabolism and signaling pathways like MAPK or ERK activation have also been reported, suggesting the resistance to venetoclax is highly complex and involves multiple pathways. This review aimed to describe the mechanisms of resistance to venetoclax in AML, CLL, multiple myeloma, and other hematologic malignancies, as well as to propose a perspective to circumvent it.