A-1331852

A-1331852 is a highly potent and selective small-molecule inhibitor of B-cell lymphoma-extra large (Bcl-xL), a key anti-apoptotic member of the Bcl-2 family. Developed by AbbVie, it acts as a BH3 mimetic that binds with high affinity to the hydrophobic groove of Bcl-xL, thereby displacing pro-apoptotic proteins such as BAK and BAX to trigger the intrinsic apoptotic pathway. Unlike earlier dual inhibitors like navitoclax (ABT-263), A-1331852 exhibits significant selectivity for Bcl-xL over Bcl-2 and Bcl-w, which is intended to minimize certain systemic toxicities like neutropenia, although on-target thrombocytopenia remains a concern due to the reliance of platelets on Bcl-xL for survival. It is widely used in preclinical research to study tumor dormancy, senescence (as a senolytic agent), and chemoresistance in various malignancies, including breast, prostate, and lung cancers.