Role of Novel Oral Anticoagulants in the Treatment of Antiphospholipid Syndrome.

Background: Antiphospholipid syndrome (APS) is an autoimmune disease characterized by thrombosis or pregnancy loss with persistent positive antibodies. Standard treatment for APS with history of thromboembolism is heparin or low-molecular-weight heparin followed by a vitamin K antagonist (VKA). Novel oral anticoagulants (NOACs) could be effective in patients with APS, but none carry indications for treatment related to APS. Clinical Evidence: Five case reports or series with rivaroxaban and dabigatran suggest thrombotic events occur most often in the higher risk population (arterial thrombosis and/or triple positive antibodies) or in patients who had recurrent VTEs on warfarin therapy. An observational cohort in 26 APS patients using dabigatran or rivaroxaban described a recurrent thrombotic event in only 1 patient after 8 months of treatment. The event-free survival rate was 87.9% at 12 months. Three controlled clinical trials are underway to evaluate the thrombotic risk of NOACs (RAPS, TRAPS, and ASTRO-APS). Discussion: There are no completed studies that evaluate the use of NOACs in APS compared to VKAs. One major disadvantage of the NOACs is the limited availability of reversal agents for patients with a major bleeding episode. An increased risk of thrombotic events is associated with arterial occlusions and triple antibody positivity APS with both warfarin and NOACs; this is currently being researched in the TRAPS study.
Conclusion: Based on current available evidence, VKAs remain the standard of care in the treatment of APS. Results of ongoing trials may offer more guidance on how to appropriately use NOACs for patients with APS.