Use of new oral anticoagulants in antiphospholipid syndrome.

The current mainstay of treatment of thrombotic APS is long-term anticoagulation with oral vitamin K antagonists (VKA) such as warfarin. However, the use of warfarin is problematic, particularly in patients with antiphospholipid syndrome (APS). The new oral anticoagulants (NOAC) include dabigatran etexilate (Pradaxa®), a direct thrombin inhibitor, and rivaroxaban (Xarelto®), Apixaban (Eliquis) and Edoxaban (Lixiana®), which are direct anti-Xa inhibitors. Unlike warfarin, these agents do not interact with dietary constituents and alcohol, have few reported drug interactions, and monitoring of their anticoagulant intensity is not routinely required due to their predictable anticoagulant effects. In this chapter, we discuss clinical and laboratory aspects of NOAC. These agents have been approved for several therapeutic indications based on phase III prospective randomised controlled clinical trials using warfarin at a target INR of 2.5 (i.e. range 2.0-3.0) as the comparator. However these trials may not be directly applicable to patients with antiphospholipid syndrome (APS) where prospective clinical studies of NOAC are the way forward.