An orally bioavailable and selective inhibitor of the anti-apoptotic protein B-cell lymphoma 2 (Bcl-2), with potential pro-apoptotic and antineoplastic activities. Upon oral administration, lisaftoclax targets, binds to and inhibits the activity of Bcl-2. This restores apoptotic processes in tumor cells. Bcl-2 is overexpressed in many cancers and plays an important role in the negative regulation of apoptosis; its expression is associated with increased drug resistance and tumor cell survival.