BCL2 and cancer: The highly specific BCL-2 inhibitor ABT-199/venetoclax [with three orders of magnitude difference in Ki between BCL-2 (Ki < 0.010 nM) and BCL-XL (Ki = 48 nM) or BCL-W (Ki = 245 nM)] was described in 2013 and in vitro and in vivo studies with rodents suggested this would be efficacious in the clinic without platelet loss and a therapeutic window for targeting cancer cells without adverse events could be achieved [38].