TRAPS: Rivaroxaban versus warfarin for secondary prevention in antiphospholipid syndrome [Classics Series]

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

1. This study was discontinued prematurely due to excess thromboembolic and haemorrhage in patients treated with rivaroxaban compared to warfarin.

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

Original publication date: September 2018

Study overview: The rivaroxaban study in antiphospholipid syndrome (TRAPS) was discontinued early because data showed that secondary prevention with rivaroxaban in high-risk triple-positive patients with antiphospholipid syndrome (aPL) was associated with an excess of thromboembolic and bleeding events compared to warfarin. Thus, this study showed that rivaroxaban treatment was inferior to warfarin treatment in these patients. Strengths of this study are the completeness of the dataset, with no patients lost to follow-up, and the 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. In addition, since this study was limited to a very specific subgroup of high-risk patients with aPL syndrome, future research is needed to determine whether these results are generalizable to all patients with aPL syndrome. Ultimately, warfarin remains the standard of care 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) was designed to test whether rivaroxaban is non-inferior to warfarin for the prevention of thromboembolic events in high-risk patients with aPL syndrome. The study included participants aged 18-75 who were positive for all 3 aPL tests three times (lupus anticoagulant, anti-cardiolipin antibodies, and anti-b2 glycoprotein I antibodies) and had a history of a previously documented thrombotic event (n = 120). The participants were randomized to receive rivaroxaban (n = 59) or warfarin (n = 61) and were monitored for the incidence of thromboembolic events, major bleeding and vascular death. The study was stopped before completion due to 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 include ischemic stroke, myocardial infarction and major bleeding. There were no events of venous thromboembolism or deaths in the ‘as treated’ population for either the rivaroxaban or warfarin groups.

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

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