Is Ibrutinib-related Atrial Fibrillation Dose Dependent

Ibrutinib, an oral inhibitor of Bruton tyrosine kinase (BTK), has recently revolutionized the treatment of various chronic B-cell malignancies and particularly chronic lymphocytic leukemia (CLL). Atrial fibrillation (AF) has early emerged as a cardiovascular adverse effect (CVAE) of ibrutinib. In phase 3 randomized clinical trials (RCT), ibrutinib exhibits a ≈4-fold increase-risk of AF compared with controls (pooled relative-risk (RR) 3.9; 95% confidence interval (CI): (2.0-7.5); p\<0.0001). The annualized incidence rate of ibrutinib-related AF (IRAF) reporting in clinical trials is estimated to 4.9 (95% CI: 2.9-8.3) per 100 person-years. IRAF risk persists throughout ibrutinib exposition and seems to be cumulative with the extension of follow-up and cardiac monitoring. Underlying mechanisms of IRAF are not fully understood. Ibrutinib potently inhibits multiple off-target kinases at therapeutic concentrations. While a dose-reduction or an interruption of ibrutinib is mentioned in the summary of product characteristics of ibrutinib, any beneficial effect on IRAF management of such a management is unclear. The main aim of this study is to determine if IRAF is a dose-dependent CVAE in chronic B-cell malignancies patients by studying the association between ibrutinib dose and IRAF reporting in Vigibase®, the World Health Organization (WHO) pharmacovigilance database.