On December 28^th, 2012 the FDA announced the approval of Eliquis (apixaban), an oral Factor Xa inhibitor, to reduce the risk of stroke and systemic embolism in patients with non-valvular atrial fibrillation¹. The approval of Eliquis was based on two pivotal clinical trials, the ARISTOTLE and AVERROES trials.

The Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation (ARISTOTLE) study was a randomized, double-blind, head-to-head, non-inferiority trial of apixaban 5 mg twice daily versus warfarin (target INR 2.0-3.0) conducted in 18,201 patients². Results of the study established that apixaban was not inferior to warfarin in the reduction of hemorrhagic stroke. Key secondary outcomes of the trial showed apixaban superior to warfarin in preventing stroke or systemic embolism.²

The Apixaban Versus Acetylsalicylic Acid to Prevent Stroke in Atrial Fibrillation Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment (AVERROES) trial was a randomized, double-blind study of 5,599 patients with atrial fibrillation who had increased risk for stroke and were unsuitable for vitamin K antagonist therapy.³ Patients were randomized to either apixaban 5 mg twice daily or aspirin 81 to 324 mg daily. The primary outcome was the occurrence of stroke or systemic embolism³. Results of the trial showed apixaban reduced the risk of stroke or systemic embolism compared to aspirin (51 and 113; P<0.001) and had similar occurrence of major bleeding events (44 and 39; P=0.57).³

The recommended dose of apixaban is 5mg twice daily, or 2.5 mg twice daily in patients with at least two of the following: >80 years of age, <60 kg, or SCr >1.5 mg/dL.⁴ Apixaban is metabolized mainly by CYP3A4 and is a substrate of P-glycoprotein (P-gp), therefore the dose should be reduced to 2.5 mg or avoided with strong dual inhibitors of CYP3A4 and P-gp and avoided completely with strong inducers of CYP3A4 and P-gp. The major adverse effect is the increased risk of bleeding. Similar to other factor Xa
inhibitors, apixaban does not require monitoring of INR and there is no reversal agent available for the anti-coagulant effect.

Apixaban offers an alternative to other oral anticoagulants in the treatment of atrial fibrillation, such as warfarin, dabigatran, and rivaroxaban. Clinicians should use care in selecting appropriate therapy based on patient specific factors and be mindful of apixaban’s potential for drug-drug interactions.

References

1. Food and Administration. FDA approves Eliquis to reduce the risk of stroke, blood clots in patients with non-valvular atrial fibrillation. Retrieved from: http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm333634.htm.
2. Granger CB, Alexander JH, McMurray JJ, et al. Apixaban versus warfarin in patients with atrial fibrillation. N Engl J Med. 2011 Sep 15. 365(11):981-992.
3. Connolly SJ, Eikelboom J, Joyner C, et al. Apixaban in patients with atrial fibrillation. N Engl J Med. 2011 Mar 3. 364(9):806-817.
4. Eliquis [package insert]. Princeton, NJ: Bristol-Myers Squibb; 2012.