An orally bioavailable inhibitor of the anti-apoptotic protein B-cell lymphoma 2 (Bcl-2), with potential pro-apoptotic and antineoplastic activities. Upon oral administration, sonrotoclax specifically binds to and inhibits the activity of the pro-survival protein Bcl-2. This restores apoptotic processes and inhibits cell proliferation in Bcl-2-overexpressing tumor cells. Bcl-2, a protein that belongs to the Bcl-2 family, is overexpressed in various tumor cell types and plays an important role in the negative regulation of apoptosis. Its tumor expression is associated with increased drug resistance and cancer cell survival.