Apixaban: a novel oral inhibitor of factor Xa

The pharmacology, pharmacokinetics, efficacy, and safety of apixaban are reviewed.

Apixaban is an oral, direct, selective factor Xa inhibitor with a rapid onset of action. It has a plasma elimination half-life of 12 hours and has been administered in a twice-daily dosing regimen in clinical trials without the need for anticoagulation monitoring or dosage adjustment. Apixaban has multiple elimination pathways, and its pharmacokinetics is not substantially altered by patient age, sex, race, or ethnicity. The results of three Phase III trials indicated that apixaban was similar to or more effective than enoxaparin for preventing venous thromboembolism (VTE) in patients undergoing total hip or knee replacement, with similar or lower rates of bleeding. Two Phase III trials found that apixaban was more effective for stroke prevention than either aspirin or warfarin in patients with atrial fibrillation (AF), with a similar (versus aspirin) or improved (versus warfarin) safety profile. A Phase III trial evaluating apixaban plus antiplatelet monotherapy or dual-antiplatelet therapy in patients with acute coronary syndrome ended early due to clear evidence of a clinically important increase in bleeding among patients randomized to apixaban without any meaningful reduction in ischemic events. The adverse-event profiles for apixaban and comparators have been similar in studies conducted to date.

Apixaban, a new anticoagulant, appears to offer an efficacy and safety profile comparable with that of enoxaparin for preventing VTE after orthopedic surgery, with the advantage of oral administration. In patients with AF, apixaban is more effective than either warfarin or aspirin for stroke prevention, with an acceptable safety profile.