Abdulraheem Yacoub, MD, The University of Kansas Health System, Fairway, KA, details the rationale of two Phase III studies evaluating parsaclisib in patients with myelofibrosis (MF). The first study discussed by Dr Yacoub investigates the use of parsaclisib plus ruxolitinib in patients with myelofibrosis who have previously had suboptimal responses to ruxolitinib. The second study discussed tests this combination in patients with myelofibrosis who are JAK- and PI3K-inhibitor treatment-naive. This interview took place at the virtual American Association for Cancer Research (AACR) Annual Meeting 2021.