Efficacy and Safety of Apixaban Versus Warfarin in Patients with Atrial Fibrillation and a History of Cancer: Insights from the ARISTOTLE Trial.

Background: Cancer is associated with a prothrombotic state and increases the risk of thrombotic events in patients with atrial fibrillation. We described the clinical characteristics and outcomes and assessed the safety and efficacy of apixaban versus warfarin in patients with atrial fibrillation and cancer in the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) trial.
Methods: The association between cancer and clinical outcomes was assessed using Cox regression models. At baseline, 1236 patients (6.8%) had a history of cancer; 12.7% had active cancer, and 87.3% had remote cancer.
Results: There were no significant associations between history of cancer and stroke/systemic embolism, major bleeding, or death. The effect of apixaban versus warfarin for the prevention of stroke/systemic embolism was consistent among patients with a history of cancer (event/100 patient-years = 1.4 vs 1.2; hazard ratio [HR], 1.09; 95% confidence interval [CI], 0.53-2.26) and no cancer (1.3 vs 1.6; HR, 0.77; 95% CI, 0.64-0.93) (P interaction = .37). The safety and efficacy of apixaban versus warfarin were preserved among patients with and without active cancer. Apixaban was associated with a greater benefit for the composite of stroke/systemic embolism, myocardial infarction, and death in active cancer (HR, 0.30; 95% CI, 0.11-0.83) versus without cancer (HR, 0.86; 95% CI, 0.78-0.95), but not in remote cancer (HR, 1.46; 95% CI, 1.01-2.10) (interaction P = .0028).
Conclusions: Cancer was not associated with a higher risk of stroke. The superior efficacy and safety of apixaban versus warfarin were consistent in patients with and without cancer. Our positive findings regarding apixaban use in patients with atrial fibrillation and cancer are exploratory and promising, but warrant further evaluation.
(Copyright © 2017 Elsevier Inc. All rights reserved.)