Bristol-Myers Squibb Company and Pfizer Inc. announced the main results of the phase 3 clinical trial ARISTOTLE, which evaluated Eliquis (apixaban) compared to warfarin for the prevention of stroke or systemic embolism in 18,201 patients with atrial fibrillation and at least one risk factor for stroke. In the ARISTOTLE trial, Eliquis as compared with warfarin significantly reduced the risk of stroke or systemic embolism by 21 per cent, major bleeding by 31 per cent, and mortality by 11 per cent. Results were presented during the Hot Line session at the European Society of Cardiology Congress in Paris, France, and published in The New England Journal of Medicine.

Conducted in 1,034 centres in 39 countries, the study was coordinated by the Duke Clinical Research Institute, Durham, N.C., and Uppsala Clinical Research Institute, Uppsala, Sweden.

“The risk for stroke in patients with atrial fibrillation is a major public health concern in an aging population,” said Dr Christopher B. Granger, professor of medicine, Duke Clinical Research Institute, Duke University Medical Center, Durham, N.C., and lead investigator of the study. “We are therefore encouraged by the outcome of the ARISTOTLE trial, which showed that apixaban, as compared with warfarin, significantly reduced the risk of stroke or systemic embolism, major bleeding, and mortality.”

Eliquis, a new oral direct Factor Xa inhibitor, is part of a class of agents being studied for their potential to prevent and treat blood clots.

Atrial fibrillation is the most common sustained cardiac arrhythmia, or irregular heart beat. It is estimated that more than 5 million Americans and 6 million individuals in the European Union have atrial fibrillation. The lifetime risk of atrial fibrillation is estimated to be approximately one in four for individuals 40 years of age or older. The most serious medical issue for individuals with atrial fibrillation is the increased risk of stroke, which is five times higher in people with atrial fibrillation than those without atrial fibrillation. In fact, 15 per cent of all strokes are attributable to atrial fibrillation in the US Additionally, strokes due to atrial fibrillation are more burdensome than strokes not due to atrial fibrillation. Atrial fibrillation-related strokes are more severe than other strokes with an associated 30-day mortality of 24 per cent and a 50 per cent likelihood of death within one year.

ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation), a randomized, double-blind, multicentre, head-to-head trial, included 18,201 patients with atrial fibrillation and at least one additional risk factor for stroke. The mean CHADS2 risk score for the study population was 2.1. Patients were randomized to receive either apixaban (n=9,120) 5 mg twice daily (2.5 mg twice daily in selected patients) or warfarin (n=9,081) dosed to achieve a target INR (International Normalized Ratio) of 2.0-3.0.

The key study outcomes were prespecified in a hierarchical manner that sequentially tested apixaban versus warfarin for noninferiority on the composite endpoint of stroke or systemic embolism; superiority on the composite endpoint of stroke or systemic embolism; superiority on major bleeding; and superiority on all-cause death. The efficacy analyses included all randomized patients (“intention to treat”); bleeding analyses were “on treatment” and included all randomized patients who received at least one dose of study drug. Eliquis demonstrated non-inferiority (p<0.001) for the primary efficacy outcome, composite of stroke or systemic embolism, compared with warfarin. The relative risk reduction was 21 percent with annual event rates of 1.27 per cent for Eliquis and 1.60 per cent for warfarin in an intention to treat analysis. Additionally, Eliquis met the key secondary objective of superiority for the primary outcome of the composite of stroke or systemic embolism (p=0.01). The predominant effect on stroke prevention was on hemorrhagic stroke, which was 49 per cent lower with Eliquis than warfarin, along with an effect on ischemic or uncertain stroke that was 8 per cent lower with Eliquis than with warfarin.

Results from ARISTOTLE also demonstrated that Eliquis was superior to warfarin for the primary safety outcome of ISTH major bleeding (p<0.001), yielding a significant relative risk reduction of 31 per cent, with annual event rates of 2.13 for Eliquis and 3.09 for warfarin. Additionally, Eliquis significantly reduced the risk for ISTH major or clinically relevant non-major bleeding by 32 per cent (p<0.001) compared to warfarin. Any bleeding was reduced 29 percent per year compared with warfarin (p<0.001). With Eliquis, the risk for intracranial haemorrhage was significantly reduced by 58 per cent compared with warfarin (p<0.001). Fatal bleeding (including fatal hemorrhagic stroke) was numerically lower with Eliquis (10) than warfarin (27), in an on treatment analysis.

ARISTOTLE demonstrated that Eliquis is the first novel oral anticoagulant to significantly reduce all-cause death compared to warfarin. For the prespecified key secondary efficacy outcome of all-cause death, ELIQUIS was superior to warfarin (p=0.047). Specifically, there was a statistically significant 11 per cent relative risk reduction with Eliquis compared to warfarin, with annual event rates of 3.52 per cent and 3.94 per cent, respectively.

Eliquis is the approved trade name for apixaban in Europe and the proposed trade name in the US Eliquis is not approved for the prevention of stroke or systemic embolism in patients with atrial fibrillation in any country. Bristol-Myers Squibb and Pfizer recently announced the first regulatory approval for Eliquis in the 27 countries of the European Union (EU) for the prevention of venous thromboembolic events (VTE) in adult patients who have undergone elective hip or knee replacement surgery.

Eliquis is being investigated within the EXPANSE Clinical Trials Program, which is projected to include nearly 60,000 patients worldwide across multiple indications and patient populations and includes a total of nine completed or ongoing, randomized, double-blind phase 3 trials, including ARISTOTLE. The Eliquis atrial fibrillation clinical trial program, which includes ARISTOTLE and AVERROES, was designed to comprehensively evaluate ELIQUIS in approximately 24,000 patients with atrial fibrillation, including patients who are expected or demonstrated to be unsuitable for vitamin K antagonist (VKA) therapy.