B-PO03-172 PREDICTORS OF IBRUTINIB TREATMENT INTERRUPTION SECONDARY TO ARRHYTHMIAS

Abstract

Ibrutinib, a tyrosine kinase inhibitor (TKI), used in chronic lymphocytic leukemia, has been associated with increased incidence of atrial fibrillation (AF); with known treatment interruptions due to intractable AF episodes. The details of arrhythmic episodes that are associated with treatment interruptions remain unclear. To determine predictors of ibrutinib treatment interruption secondary to arrhythmias. A retrospective data analysis at a single center using electronic medical records database search tools and individual chart review was conducted to identify consecutive patients who had holter monitors while on ibrutinib therapy. 72 patients who had holter monitors while on ibrutinib therapy were included in analysis. Mean age was 76.9±9.9 years, 25% were female and the average duration of ibrutinib treatment was 32.3±22 months. Ibrutinib treatment was interrupted in n=18 (25%) of patients due to arrhythmias and n=9 (12.5%) were initiated on anti-arrhythmic medications due to arrhythmias secondary to ibrutinib therapy. Interruptions in ibrutinib therapy were associated with >1% PAC burden on holter monitor while on ibrutinib therapy (p=0.002) and a prior history of VT (p=0.005); but not with >1% PVC burden (p=0.285), presence of SVT (p=0.747), AF (p=0.292) or NSVT (p=0.147) on holter monitor. Patients in whom ibrutinib was held for arrhythmias were more likely to be seen by an electrophysiology specialist (p=0.041), along with patients on ibrutinib whose holter monitors showed NSVT (p=0.011). Female patients were referred to a cardiac specialist less than their male counterparts (p=0.051). In this large dataset of holter monitors on patients treated with ibrutinib, interruptions in TKI therapy correlated with certain arrhythmia patterns that could predate intractable arrhythmias and drug cessation in the future; which can help identify patients who may benefit from closer monitoring.