CLL-129 BRUIN CLL-313: A Phase 3 Open-Label, Randomized Study of Pirtobrutinib Versus Bendamustine Plus Rituximab in Untreated Patients With Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (Trial in Progress)

Abstract

Covalent Bruton's Tyrosine Kinase (BTK) inhibitors (BTKi) have transformed the management of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), but these treatments are not curative, and the majority of patients will require additional treatment. Covalent BTKi shares pharmacologic liabilities (e.g., low oral bioavailability, short half-life) that collectively may lead to suboptimal BTK target coverage, for example in rapidly proliferating tumors with high BTK protein turnover such as accelerating CLL/SLL, ultimately manifesting as acquired resistance in some patients. To address these limitations, pirtobrutinib, a highly selective, non-covalent BTKi that inhibits both wild type (WT) and C481-mutated BTK with equal low nM potency was developed. Determine whether pirtobrutinib is superior to bendamustine plus rituximab in treatment naïve CLL/SLL patients with retained 17p. BRUIN CLL-313 is a randomized, open-label, global phase 3 study comparing pirtobrutinib monotherapy versus bendamustine plus rituximab (BR) in treatment naïve CLL/SLL patients with retained 17p. Approximately 250 patients will be randomized 1:1. Randomization will be stratified by IGHV mutation status (mutated vs unmutated), and Rai stage (low/intermediate vs high). Patients in the BR arm are eligible to crossover to pirtobrutinib monotherapy if they experience progressive disease per iwCLL 2018 and confirmed by an independent review committee (IRC). Global; community hospitals, academic medical centers. Eligible patients are adults with confirmed diagnosis of CLL/SLL and who require therapy per iwCLL 2018 criteria. Key exclusion criteria include CNS involvement by CLL/SLL, Richter's transformation to DLBCL, prolymphocytic leukemia or Hodgkin lymphoma any time pre-enrollment, presence of 17p deletion, prior systemic therapy for CLL/SLL, and significant cardiovascular disease. Oral pirtobrutinib monotherapy versus bendamustine plus rituximab. The primary endpoint is progression-free survival (PFS) per iwCLL assessed by an independent review committee. Secondary endpoints include investigator-assessed PFS, overall survival (OS), overall response rate (ORR), duration of response (DoR), safety and tolerability, and patient-reported outcomes. The global study is currently enrolling patients (NCT05023980). Trial in Progress. Trial in Progress.