Trial of Rivaroxaban in AntiPhospholipid Syndrome (TRAPS): Two-year outcomes after the study closure.

Background TRAPS was a prospective randomized open-label non-inferiority study conducted in 14 centres in Italy. Rivaroxaban was compared to warfarin for the prevention of thromboembolic events, major bleeding, and vascular death in high-risk triple-positive patients with antiphospholipid syndrome. Objective Aim of this paper is to report the events during the two years follow up after the study closure. Methods On January 28, 2018 the trial was prematurely stopped by adjudication and safety committee for an excess of events in the rivaroxaban group. Randomized patients were advised on trial results and those randomized to rivaroxaban were solicited to switch to warfarin. All the 14 participating centres were asked and accepted to follow up their patients for clinical events. This report describes the rate of events that occurred between January 28, 2018 and January 28, 2020. Results Of 120 randomized patients, 115 were available for follow up. Outcome events were 2 in 6 (33.3%) patients who remained on DOACs and 6 in 109 (5.7%) patients on warfarin (HR 6.9; 95%CI 1.4-34.5, p=0.018). The 2 patients on DOACs (one taking dabigatran and one taking rivaroxaban) suffered from thromboembolic events while of the 6 patients with composite outcomes on warfarin, 3 had thromboembolic events (HR for thrombosis 13.3; 95CI 2.2-79.9, p=0.005). Conclusion These data further support the use of warfarin in high-risk patients with APS.