A novel BTK inhibitor, acalabrutinib, is showing promise in the early clinical trial stages for chronic lymphocytic leukemia (CLL). Speaking from the American Society of Hematology (ASH) 2017 Annual Meeting and Exposition in Atlanta, GA, Susan OBrien, MD, of the University of California, Irvine, CA, discusses the benefits of acalabrutinib over ibrutinib and why this may be. Prof. OBrien highlights the main studies of this agent for CLL, including as a monotherapy (ACE-CL-001; NCT02029443) and in combination with ACP-319 (ACE-CL-002; NCT02157324) in the relapsed/refractory setting, and in the frontline setting in combination with obinutuzumab (ACE-CL-003; NCT02296918).