BCL2 and cancer: To date, two such compounds have been evaluated in the clinic: ABT-199, which specifically targets Bcl-2, and ABT-263 (Navitoclax), which antagonizes both Bcl-2 and Bcl-xL.127, 128 BH3 mimetics have demonstrated impressive clinical activity in single therapy, and recently Bcl-2/xL inhibition by ABT-263, or its non-orally available analog ABT-737, has been shown to sensitize cancer cells to TRAIL in vitro.