Abstract 16902: Efficacy and Safety of Rivaroxaban versus Warfarin in Patients Taking Non-dihydropyridine Calcium Channel Blockers: Results From the ROCKET AF Trial

Abstract

Background: Non-dihydropyridine calcium channel blockers (non-DHP CCBs) are agents commonly used for ventricular rate control in patients with atrial fibrillation (AF). The agents have the property of combined cytochrome 3A4 and P-glycoprotein (P-gp) inhibition which may lead to increased drug exposure for oral anticoagulants that are substrates for these pathways. We investigated the safety and efficacy of rivaroxaban versus warfarin according to use of these agents. Objectives: This post-hoc analysis examined patient characteristics and compared outcomes between rivaroxaban and warfarin using Cox proportional hazards modeling according to the use of non-DHP CCBs at baseline in ROCKET AF (n=14,264). Methods and Results: At the time of randomization, 1308 patients (9.2%) were taking a non-DHP CCBs. Patients taking a non-DHP CCB were more likely to be female (45% vs. 39%), have diabetes (43% vs. 40%), and have a medical history of COPD (21% vs. 9%) while they were less likely to have a medical history of heart failure (49% vs. 64%), myocardial infarction (14% vs.18%) and had a lower mean CHADS 2 score (3.3 vs. 3.5). Non-DHP CCB use was not associated with an increased risk of stroke or non-CNS embolism (P=0.11) or the composite outcome of non-major clinically relevant or major bleeding (P=0.087). No significant difference was observed in the primary efficacy (stroke or non-CNS embolism; adjusted interaction P value=0.38) or primary safety outcome (non-major clinically relevant bleeding or major bleeding; adjusted interaction P value=0.14) between rivaroxaban and warfarin with non-DHP CCB use (Table). Conclusion: Non-DHP CCBs are commonly used medications for rate control in patients with AF. In spite of having the properties of combined P-gp and moderate CYP3A4 inhibition, use of these agents was not associated with a significant change in the efficacy or safety of rivaroxaban compared with warfarin in the ROCKET AF trial.