Duvelisib, a PI3K-δ and PI3K-γ inhibitor, was recently FDA approved for the treatment of chronic lymphocytic leukemia (CLL) patients who have relapsed after two or more lines of therapy, which was based on the results of the DUO study (NCT02004522). Here, Matthew Davids, MD, MSc, of Dana-Farber Cancer Institute, Boston, MA, discusses the results of the DUO crossover extension study, which investigated the safety and efficacy of duvelisib following disease progression on ofatumumab in relapsed/refractory CLL. This interview took place at the American Society of Hematology (ASH) 2018 Annual Meeting and Exposition, held in San Diego, CA.