BCL2L1 and B-cell chronic lymphocytic leukemia: ABT-737, which binds to BCL-2, BCL-XL, and BCL-w with high affinity, had promising preclinical effects in CLL.468,469 Navitoclax (ABT-263), the orally available derivative of ABT-737,470 was shown to provoke transient thrombocytopenia in phase 2 trials of patients with B-NHLs due to the importance of BCL-XL for the survival of platelets.471 A phase 1 trial of navitoclax combined with rituximab (NCT00788684) in lymphoid cancers is ongoing.