TRAPS: Rivaroxaban vs. Warfarin for Secondary Prevention in Antiphospholipid Syndrome [Classics Series]

This study summary is an excerpt from the book 2 Minute Medicine’s The Classics in Medicine: Summaries of the Landmark Trials

1. This study was halted prematurely due to an excess of thromboembolic and bleeding events in patients treated with rivaroxaban compared to warfarin.

2. There were no deaths from thromboembolic or bleeding events in either group.

Original Date of Publication: September 2018

Study Rundown: The Trial on rivaroxaban in AntiPhospholipid Syndrome (TRAPS) was halted early as data showed that secondary prevention with rivaroxaban in high-risk triple-positive patients with antiphospholipid (aPL) syndrome was associated with an excess of thromboembolic and bleeding events compared to warfarin. Thus, this trial showed that treatment with rivaroxaban in these patients was inferior to treatment with warfarin. Strengths of this study include the completeness of its dataset, with no patients lost to follow-up, and its characterization of thromboembolic and bleeding outcomes. However, this study is limited by its relatively small sample size, the fact that it was not blinded, and of course, its early termination. Furthermore, as this study was restricted to a very specific subset of high-risk patients with aPL syndrome, future research is needed to determine if these results are generalizable to all patients with aPL syndrome. Ultimately, warfarin remains the standard of treatment in high-risk patients with aPL syndrome, as rivaroxaban is associated with increased adverse clinical outcomes.

Click to read the study in Blood

In-Depth [randomized control trial]: The Trial on Rivaroxaban in AntiPhospholipid Syndrome (TRAPS) sought to test whether rivaroxaban is non-inferior to warfarin for prevention of thromboembolic events in high-risk patients with aPL syndrome. The study included participants aged 18-75 who were triple positive for all 3 aPL tests (lupus anticoagulant, anti- cardiolipin antibodies, and anti– b2-glycoprotein I antibodies) and had a history of a previously documented thrombotic event (n = 120). Participants were randomized to receive rivaroxaban (n = 59) or warfarin (n = 61) and were followed for incidence of thromboembolic events, major bleeding, and vascular death. The trial was stopped prior to completion for an excess of events in the patients treated with rivaroxaban compared to warfarin (11 vs. 2, respectively, HR 6.7; 95%CI 1.5-30.5; p = 0.01). Events included ischemic stroke, myocardial infarction, and major bleeding. There were no venous thromboembolism events nor any deaths in the ‘as treated’ population for either the rivaroxaban nor the warfarin group.

Pengo V, Denas G, Zoppellaro G, Jose SP, Hoxha A, Ruffatti A, et al. Rivaroxaban vs warfarin in high-risk patients with antiphospholipid syndrome. Blood. 2018 Sep 27;132(13):1365–71.

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