This study is a prospective, open-label, blinded event, pilot study that will randomize patients with a history of venous thrombosis and antiphospholipid syndrome (APS) already receiving anticoagulation to either warfarin or apixaban. The study will assess the safety and efficacy of apixaban compared with adjusted dose warfarin for the prevention of recurrent thrombosis (defined as the aggregate of arterial or venous thrombosis) and vascular death. The primary efficacy outcome will be confirmed upon adjudication by a panel blinded to the treatment arm. The primary safety outcome will be major bleeding and clinically relevant non-major bleeding events. Patients who consent to study participation will be randomized to anticoagulation with adjusted dose warfarin sodium or apixaban 5 mg by mouth twice daily. This pilot study will also provide information and experience identifying, recruiting, enrolling and randomizing patients with APS and a history of venous thrombosis to anticoagulation with apixaban or warfarin for the prevention of recurrent thrombosis.
This study is designed to compare the safety and effectiveness of two blood thinners, apixaban and warfarin, for the prevention of blood clots in patients who have a higher risk of blood clots than the general population, a condition called antiphospholipid syndrome.