Treatment Effectiveness with Venetoclax-Based Therapy after Bruton Tyrosine Kinase Inhibitors in Chronic Lymphocytic Leukemia: An International Real-World Study

Abstract

Introduction: Venetoclax has demonstrated consistent efficacy and manageable toxicity in patients with previously untreated or relapsed/refractory (R/R) chronic lymphocytic leukemia/small lymphocytic leukemia (CLL/SLL). However, evidence on venetoclax use in patients previously treated with Bruton tyrosine kinase inhibitors (BTKi) is limited. This real-world evidence (RWE) study assessed clinical outcomes of patients who received venetoclax after covalent BTKi (cBTKi) therapy, i.e., response rates, time to next treatment or death (TTNT-D), and progression-free survival (PFS), overall and stratified by line of therapy. Methods: The CLL Collaborative Study of Real-World Evidence (CORE), a retrospective, international, observational study (23 centers) provided data for this analysis. Adult patients diagnosed with CLL/SLL were included if they received a venetoclax-based regimen after discontinuation of a cBTKi-based regimen. Baseline characteristics at venetoclax initiation were summarized using descriptive statistics. Overall response rate (ORR) was calculated as the proportion of patients with complete response (CR) or partial response (PR) among patients with documented responses as recorded in the patients' medical charts based on physician assessment. TTNT-D was measured from date of venetoclax initiation to change of treatment/death (event) or end of follow-up, while PFS was measured from date of venetoclax initiation to disease progression/death (event) or end of follow-u…