Abstract Introduction Zanubrutinib, a second-generation Bruton tyrosine kinase inhibitor (BTKi), is approved for the treatment of previously-treated chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) (NCT04116437). Real-world evidence, however, remains limited regarding the effectiveness of zanubrutinib in patients with CLL/SLL who switch from another BTK inhibitor. This retrospective, observational study examined the demographic and clinical characteristics, treatment patterns, reasons for treatment change, and treatment-limiting treatment-related adverse events (AEs) in patients with CLL/SLL who initiated zanubrutinib following an immediate switch from ibrutinib or acalabrutinib. The study utilized electronic medical record data from the Florida Cancer Specialists 61.1% of patients who switched from ibrutinib and 58.7% who switched from acalabrutinib, remained on treatment. Of the 40.0% of patients who discontinued zanubrutinib therapy, reasons for discontinuation included AEs (40.0%), disease progression (22.5%), patient choice (10.0%), or another reason (27.5%). The most common treatment-related AE was rash (18.8%; n=3). ConclusionThis real-world study examined initiation of zanubrutinib following an immediate switch from a previous BTKi among patients with CLL/SLL. The primary reason patients switched from their previous BTKi was AEs, including atrial fibrillation, fatigue, and rash. Following the switch to zanubrutinib, recurrence of AEs was uncommon, and most patients stayed on treatment. These results support previously reported findings that zanubrutinib for CLL/SLL is well-tolerated despite prior BTKi therapy.
Hernandez et al. (Mon,) studied this question.