Efficacy and Safety of Parsaclisib in Patients with Relapsed or Refractory Follicular Lymphoma: Primary Analysis from a Phase 2 Study (CITADEL-203)

Background: Follicular lymphoma (FL) is the second most common form of non-Hodgkin lymphoma (NHL) in Western countries, accounting for 20-30% of all NHLs (Hübel K. Hemasphere. 2020;4:e317). While most patients (pts) respond well to first-line therapy, they typically experience frequent relapses and progressively shorter duration of response with subsequent lines of therapy (Batlevi CL. Blood Cancer J. 2020;10:74; Rivas-Delgado A. Br J Haematol. 2019;184:753-9), and increasingly refractory disease with limited treatment options. Thus, there is an unmet need for effective treatment options for pts with relapsed or refractory (R/R) FL. Parsaclisib is a potent, highly selective, next-generation phosphatidylinositol 3-kinase (PI3K)δ inhibitor. Here we report results of the primary analysis of CITADEL-203 (NCT03126019, EudraCT 2017-001624-22), a phase 2, multicenter, open-label study of parsaclisib monotherapy in R/R FL.