The number of NOACs that have been approved or are under clinical development reflects the huge clinical demand for such medicines and the desire of the pharmaceutical industry to respond to the as yet unmet needs of patients.
Four NOACs, the direct thrombin inhibitor dabigatran etexilate and the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban, have already successfully completed phase III trials for indications requiring long-term anticoagulation. These drugs largely correspond to the requirements of an ideal anticoagulant. Furthermore, as they all participate in late stages of the coagulation cascade, their inhibition allows disruption of both the intrinsic and the extrinsic pathways; their high antithrombotic efficacy stems from this ‘double’ action.