Abstract
The purpose of this communication is to provide a brief update of our observations to date that have led to substantive modifications to the study protocol we reported previously in Clinical and Applied Thrombosis/Hemostasis. 1 Apixaban for the Secondary Prevention of Thrombosis Among Patients With Antiphospholipid Syndrome (ASTRO-APS) is a prospective randomized open-label blinded event pilot study comparing apixaban with dose-adjusted warfarin (target international normalized ratio range: 2-3) for the secondary prevention of thromboembolism among patients with a clinical history of APS and thrombosis. This phase IV pilot study is designed to provide data regarding the aspects of feasibility for enrolling patients with APS, and to estimate event rates surrounding efficacy and safety of apixaban compared with usual care for the prevention of recurrent thrombosis among patients with APS (http://clinicaltrials.gov; NCT02295475).
The primary clinical outcomes reported are rates of thrombosis (arterial or venous) and death caused by thrombosis, as well as major bleeding plus clinically relevant nonmajor bleeding over 1 year.
Upon accrual of the first 25 patients, a prespecified Data Safety Monitoring Board (DSMB) review was convened and recommended the protocol be modified to use apixaban 5 mg twice a day instead of 2.5 mg twice a day. A subsequent 5 patients were enrolled during which a possibly higher than expected rate of stroke among patients with a history of stroke randomized to apixaban was observed. This lead to an unscheduled early meeting of the DSMB. The DSMB recommendations at that time were 3-fold: (1) to continue ASTRO-APS; (2) to enroll only patients with clinical APS and a history of venous thrombosis (excluding patients with prior arterial thrombosis from enrollment); (3) to obtain a brain magnetic resonance imaging for all otherwise eligible candidates, then enroll those patients without radiographic evidence of prior stroke or white matter changes disproportionate for patient age. The ASTRO-APS is actively screening and endeavors to enroll 200 patients.
