Abstract

TPS7088 Background: Bruton tyrosine kinase (BTK) inhibitors have significantly improved survival in patients (pts) with chronic lymphocytic leukemia (CLL). Nemtabrutinib is a reversible noncovalent inhibitor of wild-type and C481-mutated BTK that has shown promising antitumor activity in pts with CLL (Woyach JA et al. Cancer Discovery 2023). In this ongoing trial, we evaluate the efficacy and safety of nemtabrutinib versus investigator’s choice of ibrutinib or acalabrutinib in pts with untreated CLL/small lymphocytic lymphoma (SLL) requiring therapy (NCT06136559). Methods: This randomized, open-label, parallel group, active-controlled phase 3 trial will enroll approximately 1200 pts aged ≥18 years. Eligible pts will have confirmed CLL/SLL with active disease based on the IWCLL criteria, which include one of the following: 1) progressive marrow failure or lymphocytosis, 2) massive, progressive, or symptomatic splenomegaly or lymphadenopathy, 3) autoimmune complications, 4) extranodal involvement, or 5) disease-related symptoms. The study will enroll patients who are treatment naïve, with an ECOG performance status 0-2, adequate organ function, and provide blood, bone marrow, and/or a lymph node sample. Pts are excluded if they have Richter Transformation, central nervous system (CNS) involvement by CLL/SLL, an active second malignancy, or a severe bleeding disorder. Pts will be randomized 1:1 to receive oral nemtabrutinib 65 mg QD, or investigator’s choice of oral ibrutinib 420 mg QD or acalabrutinib 100 mg BID. Randomization will be stratified by TP53aberration, clinical stage, investigator’s choice of comparator, and region. Treatment will continue on both arms until unacceptable toxicity, disease progression, or withdrawal. Disease response assessments by physical examination, constitutional symptoms, imaging, and evaluation of blood and bone marrow will be performed Q12W up to week 97, and Q24W thereafter. Primary efficacy endpoints are objective response (OR) and progression free survival (PFS) by BICR per iwCLL 2018 criteria. Secondary endpoints are overall survival (OS), duration of response (DOR) by BICR per iwCLL 2018, and safety. OR will be tested via a non-inferiority comparison, while PFS and OS will be tested for superiority. Adverse events will be monitored throughout the trial and graded per NCI CTCAE v5.0 and iwCLL scales. Enrollment in this trial is ongoing. Clinical trial information: NCT06136559 .