An orally bioavailable Bcl-xL inhibitor; selectively binds Bcl-xL over Bcl-2, Mcl-1, and Bcl-W (Kis = in vitro (EC50s = 6 and >5,000 nM, respectively); inhibits tumor growth in a MOLT-4 mouse xenograft model at 25 mg/kg; inhibits tumor growth and increases the antitumor activity of docetaxel in MDA-MB-231 LC3 metastatic breast cancer and NCI-H1650 non-small cell lung cancer mouse xenograft models at 25 mg/kg