Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Rivaroxaban trends toward higher thrombotic risk than vitamin K antagonists in APS

Key clinical point: Patients with thrombotic antiphospholipid syndrome may have a greater risk of recurrent thrombosis when taking rivaroxaban instead of vitamin K antagonists.

Major finding: Within a 3-year time frame, 11.6% of patients taking rivaroxaban had recurrent thrombosis, compared with 6.3% of patients taking vitamin K antagonists.

Study details: A randomized noninferiority trial involving 190 adults with thrombotic antiphospholipid syndrome.

Disclosures: The study was funded by Bayer Hispania. One coauthor reported additional relationships with Pfizer, Lilly, Janssen, and others.


Ordi-Ros J et al. Ann Intern Med. 2019 Oct 15. doi: 10.7326/M19-0291.


The recent trial by Ordi-Ros et al. revealed similar findings to a previous trial, TRAPS, by Pengo et al., which compared rivaroxaban with warfarin among patients with thrombotic antiphospholipid syndrome and triple positivity for antiphospholipid antibodies. Despite the caveat that TRAPS was prematurely terminated, in both studies, a higher proportion of patients in the rivaroxaban group than the vitamin K antagonist group had thrombotic events, most of which were arterial, whether considering MI or stroke. Furthermore, both studies did not show noninferiority of rivaroxaban versus dose-adjusted vitamin K antagonists.

The reasons for this failure of noninferiority remain unclear.

Denis Wahl, MD, PhD, and Virginie Dufrost, MD, are with the University of Lorraine, Nancy, France, and the Centre Hospitalier Universitaire de Nancy. No conflicts of interest were reported. His remarks are adapted from an accompanying editorial (Ann Intern Med. 2019 Oct 15. doi: 10.7326/M19-2815).