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Parsaclisib in BTK Inhibitor–Naive Relapsed or Refractory Mantle Cell and Marginal Zone Lymphomas

By: Julia Fiederlein
Posted: Thursday, February 10, 2022

Tycel Phillips, MD, of the University of Michigan, Ann Arbor, and colleagues conducted the phase II CITADEL-204 trial to evaluate the safety and efficacy of parsaclisib in patients with marginal zone lymphoma. Additionally, the phase II CITADEL-205 trial was conducted by Amitkumar Mehta, MD, of the University of Alabama at Birmingham (UAB) School of Medicine, and colleagues to assess this next-generation PI3K-delta inhibitor in patients with mantle cell lymphoma. The primary analyses of both trials, which were presented during the 2021 American Society of Hematology (ASH) Annual Meeting & Exposition (Abstracts 44 and 382, respectively), suggested parsaclisib monotherapy is safe and active in these populations.

In both trials, patients with Bruton’s tyrosine kinase (BTK) inhibitor–naive relapsed or refractory disease were administered 20 mg of parsaclisib once daily for 8 weeks. They were subsequently treated with 20 mg once weekly (CITADEL-204: n = 28; CITADEL-205: n = 31) or 2.5 mg once daily (CITADEL-204: n = 72; CITADEL-205: n = 77).

In the CITADEL-204 trial, the objective response rate was 58% in all patients and 58.3% in those who received once-daily dosing; the complete response rates were 6% and 4.2%, respectively. Treatment-emergent adverse events occurred in 96% of patients (grade ≥ 3: 63%). Diarrhea (47%) and cough (23%) were the most frequently reported treatment-emergent adverse events.

In the CITADEL-205 trial, the objective response rates in all patients and in those who received once-daily doing were 68.5% and 70.1%, respectively. The complete response rate was 17.6% in all patients and 15.6% in those who received once-daily dosing. A total of 90.7% of patients experienced a treatment-emergent adverse event (grade ≥ 3: 62%). The most frequently reported treatment-emergent adverse events were diarrhea (34.3%), pyrexia (17.6%), and constipation (13%).

Disclosure: For full disclosures of the authors of the CITADEL-204 trial, visit For full disclosures of the authors of the CITADEL-205 trial, visit

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