At the 58th American Society of Hematology (ASH) Annual Meeting & Exposition, John Gribben, MD, DSc, and Stephan Stilgenbauer, MD, discuss a single-arm, multicenter phase 2 clinical trial of monotherapy with the selective BCL-2 inhibitor venetoclax (ABT-199/GDC-0199) in patients with ultra-high-risk relapsed/refractory chronic lymphocytic leukemia (CLL) with 17p deletion.