Apixaban is a compound being investigated as an anticoagulant

Anticoagulant

An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...

. It is a direct factor Xa inhibitor

Direct factor Xa inhibitor

Direct factor Xa inhibitors are a class of anticoagulant drugs which act directly upon Factor X in the coagulation cascade, without using antithrombin as a mediator.-Clinical uses:Direct factor Xa inhibitors are being used clinically...

. It is presently undergoing phase III trials in the prevention of venous thromboembolism, together with a number of related competing compounds, such as rivaroxaban

Rivaroxaban

Rivaroxaban is an oral anticoagulant invented and manufactured by Bayer; in a number of countries it is marketed as Xarelto. In the United States, it is marketed by Janssen Pharmaceutica. It is the first available orally active direct factor Xa inhibitor. Rivaroxaban is well absorbed from the gut...

. It is being developed in a joint venture by Pfizer

Pfizer

Pfizer, Inc. is an American multinational pharmaceutical corporation. The company is based in New York City, New York with its research headquarters in Groton, Connecticut, United States...

 and Bristol-Myers Squibb

Bristol-Myers Squibb

Bristol-Myers Squibb , often referred to as BMS, is a pharmaceutical company, headquartered in New York City. The company was formed in 1989, following the merger of its predecessors Bristol-Myers and the Squibb Corporation...

.

Clinical trials

A 2007 trial showed that apixaban was equivalent to enoxaparin/open-label heparin in preventing thrombosis in patients who had undergone a knee replacement. A 2010 trial showed that apixaban was superior to enoxaparin in preventing thrombosis in patients undergoing elective hip replacement surgery, with similar bleeding rates.

A 2011 trial showed that in patients with atrial fibrillation who have failed or are not candidates for Vitamin K antagonist therapy, apixaban, as compared with aspirin, reduced the risk of stroke or systemic embolism in patients experiencing atrial fibrillation by more than 50% (from 3.7% per year with aspirin to 1.6% per year with Apixaban). Difference in death rates did not reach statistical significance. A 2011 trial showed that patients receiving apixaban after acute coronary syndrome experienced an increased rate of major bleeding episodes without a significant reduction in recurrent ischemic events. For this reason, the trial was terminated early.

In a head-to-head study of apixaban versus warfarin

Warfarin

Warfarin is an anticoagulant. It is most likely to be the drug popularly referred to as a "blood thinner," yet this is a misnomer, since it does not affect the thickness or viscosity of blood...

, apixaban meet both its primary endpoint (“noninferiority” to warfarin in preventing strokes) and a key secondary endpoint (superior compared to warfarin in avoiding major bleeding).