Parsaclisib has acceptable safety and promising efficacy as third-line or later therapy among patients with relapsed or refractory (R/R) follicular lymphoma (FL), according to updated results of a phase 2 trial presented in a poster session at the 2022 ASCO Annual Meeting.
“FL is a common subtype of indolent lymphomas and accounts for about 10% of all non-Hodgkin lymphoma cases. Currently, there is no standard treatment for third-line or higher FL patients,” explained presenting investigator Zhong Zheng, MD, of the Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital, and Shanghai Jiao Tong University School of Medicine, Shanghai, China.
The multicenter, single-arm phase 2 study (ClinicalTrials.gov Identifier: NCT04298879) evaluated parsaclisib, a potent, highly selective, next-generation phosphoinositide 3-kinase-delta (PI3Kd) inhibitor, among 61 patients with histologically confirmed grade 1, 2, or 3a FL who had received 2 or more prior lines of therapy. The patients were treated with 20 mg daily parsaclisib for 8 weeks followed by 2.5 mg daily parsaclisib until disease progression or intolerable toxicity. The primary outcome was the objective response rate (ORR).
The study population was 57.4% male and the median age was 50 years (range, 29-75). The majority of patients, 59.0%, had an Eastern Cooperative Oncology Group score of zero; disease was stage IV in 55.7% and stage III in 36.1%. The cohort predominantly had refractory FL (73.8% refractory, 26.2% relapsed), and 55.7% of patients had received only 2 prior lines of therapy.
At a median follow-up of 9.5 months, the median duration of treatment was 251 days (range, 23-589), or about 35.9 weeks. The ORR was 86.9%, with 31.1% of patients achieving complete response and 55.7% partial response.
The median time to response was 8.0 weeks and the median duration of response was not reached.
Among the patients with response, 81.1% retained response as of the data cutoff, whereas 17.9% had disease progression. Three patients died during the study period.
Treatment-emergent adverse events (TEAEs) occurred among 95.1% of patients, with neutrophil count decrease (49.2%) and white blood cell count decrease (32.8%) occurring most frequently.
Among grades 3 or higher TEAEs (seen in 44.3% of patients), the most common was neutrophil count decrease (16.4%). A TEAE led to death in 1 patient who developed multiple organ dysfunction syndrome, although this event was considered unrelated to treatment by the investigator.
This study was limited by its open-label design and lack of a comparator arm.
“To conclude, parsaclisib demonstrated promising efficacy and a manageable safety profile. These results suggest that parsaclisib could benefit third-line or higher R/R FL patients,” stated Dr Zheng.
Disclosure: This research was supported by Innovent Biologics. Please see the original reference for a full list of disclosures.
Zheng Z, Zhang H, Zhou K, et al. A phase II, multicenter, single-arm study of parsaclisib, a PI3Kδ inhibitor, in relapsed or refractory follicular lymphoma in China: Updated data from the study. Presented at ASCO 2022; June 3-7, 2022. Abstract 7574.