Abdulraheem Yacoub, MD, The University of Kansas Health System, Fairway, KA, outlines the results of a Phase II study evaluating the addition of parsaclisib, a PI3Kdelta inhibitor, in patients with myelofibrosis (MF) who have had suboptimal responses to ruxolitinib under the rationale that suboptimal response to ruxolitinib in this patient population may occur due to persistent PI3K/AKT pathway activation. The addition of parsaclisib demonstrated efficacy in patients with myelofibrosis experiencing suboptimal responses to ruxolitinib with an acceptable safety profile. This interview took place at the virtual American Association for Cancer Research (AACR) Annual Meeting 2021.