BCL2 and B-cell chronic lymphocytic leukemia: On the other hand, navitoclax, the first BH3-mimetic drug to inhibit Bcl-2, Bcl-xL, and Bcl-W, showed clinical efficacy in CLL patients in clinical trials, but because platelet survival is dependent on Bcl-xL, dose-limiting thrombocytopenia has hampered drug development in the clinical setting [157].