Developments in factor Xa inhibitors for the treatment of thromboembolic disorders.

Thromboembolic diseases are the leading causes of morbidity and mortality in the developed world. Anticoagulants provide effective treatment for venous or arterial thromboembolism. Two coagulation factors, factor Xa (fXa) and thrombin, are the primary targets under active investigation for anticoagulant therapy. fXa, in contrast to the multifunctional roles of thrombin in the coagulation cascade, converts prothrombin to thrombin collectively at the junction of the intrinsic and extrinsic pathway of coagulation. The effectiveness of fXa inhibitors as antithrombotic agents and their potentially reduced bleeding risks may offer superior therapeutic profiles with respect to thrombin inhibitors. After decades of research, many fXa inhibitors are now in the advanced stages of clinical trials. Unlike most reviews, which only provide incremental updates, this review provides an overview of fXa and the medicinal chemistry of its inhibitors. Overviews on coagulation models, antithrombotic therapy, and fXa will be provided, followed by the evolution of the medicinal chemistry of fXa inhibitors over the past few decades.