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Parsaclisib Safe, Tolerable in Patients With R/R FL
Parsaclisib was found to be safe and tolerable in patients with relapsed or refractory (R/R) follicular lymphoma (FL), according to data from a phase 2 study which was presented at the 2021 American Society of Hematology (ASH) Annual Meeting.
“FL is the second most common form of non-Hodgkin lymphoma (NHL) in Western countries, accounting for 20-30 percent of all NHLs. While most patients respond well to first line therapy, they typically experience frequent lapses and progressively shorter duration of response (DOR) with subsequent lines of therapy, and increasingly refractory disease with limited treatment options,” explained Ryan C. Lynch, MD, Seattle Cancer Care Alliance, University of Washington School of Medicine, Fred Hutchinson Cancer Research Center, Seattle, Washington, and co-investigators.
Thus, Dr Lynch et al reported on the primary analysis of CITADEL-201, a phase 2, multicenter, open-label study of parsaclisib monotherapy in patients with R/R FL.
Patients were enrolled in the study if they were ≥18 years of age, had histologically confirmed R/R FL (grade 1, 2, or 3a), had received ≥2 prior systemic therapies, had an Eastern Cooperative Oncology Group performance status (ECOG PS) ≤2, and were eligible for hematopoietic stem cell therapy. Prophylaxis for Pneumocystis jirovecii pneumonia was also required.
The primary endpoint was objective response rate (ORR) as determined by an independent review committee. Secondary endpoints include complete response rate (CRR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety and tolerability. All radiology-based endpoints were confirmed by an IRC.
At the data cutoff of January 15, 2021, 126 patients (median age 67.5) receive 20mg parsaclisib once daily for 8 weeks, followed by parsaclisib either 20mg once weekly (weekly dosing group, WG), or 2.5mg once daily (daily dosing group, DG). Most patients (93.7%) had an ECOG PS ≤1, 41.3% had relapse disease, and 49.2 were refractory to their most recent prior therapy. The median time since initial diagnosis was 5.95 years. More than half (54%) of patients had received 2 prior lines and 27.8 percent had received 3 prior lines.
Out of the entire patient population, 87 (69%) discontinued treatment primarily due to progressive disease (36.5%), or adverse events (AEs; 21.4%). The median treatment duration and follow-up from first dose to data cutoff were 8.5 and 20.6 months for all treated patients, and 8.4 and 17.6 months for the DG cohort. The ORR was 75.4 percent for all treated patients, and 77.7 percent for the DG. The CRR was 18.3 percent and 19.4 percent, for all patients and the DG, respectively. Among all treated patients with complete or partial response, 73.3 percent of responses occurred at first disease assessment. The median DOR was 14.7 months for both groups (all, DG). The median PFS was 14 months for all patient, and 15.8 months for the DG. The median OS was not met.
Out of 126 total patients, treatment-emergent adverse events (TEAEs) were seen in 97.6 percent (n=123) of patients (grade ≥3 in 58.7% [n=74]). The most common TEAEs were diarrhea (38.1%), nausea (24.6%), and cough (22.2%). The most common grade ≥3 TEAEs were diarrhea (11.9%) and neutropenia (10.3%). TEAEs led to dose interruptions (46.8% of patients), dose reductions (17.5%), and treatment discontinuation (23.8%). Serious TEAEs were experienced by 57 patients (45.2%) overall.
“Parsaclisib monotherapy demonstrated a rapid and durable response, had an acceptable safety profile, and was generally well tolerated in pts with R/R FL. These data suggest that parsaclisib could be a favorable treatment option for pts with R/R FL,” concluded Dr Lynch et al.—Emily Bader
Lynch R, Avigdor A, McKinney M, et al. Efficacy and Safety of Parsaclisib in Patients with Relapsed or Refractory Follicular Lymphoma: Primary Analysis from a Phase 2 Study (CITADEL-203). Presented at: the 2021 ASH Annual Meeting; Dec. 11-14; 2021; Abstract 813.
