Novel Anticoagulant Therapy of Venous Thromboembolism: Current Status and Future Directions

The first-line treatment of venous thromboembolisms (VTE) is anticoagulant therapy, and unfractionated heparin and warfarin are used in Japan. However, as both drugs require dosage adjustments that are difficult, VTE recurrences occur relatively frequently, and hemorrhagic complications are extremely common. The parenteral factor Xa inhibitor fondaparinux and the direct oral anticoagulants (DOACs) edoxaban, rivaroxaban, and apixaban have recently become available as treatments for VTE in Japan. These novel anticoagulants have more stable effects than traditional therapies and are thus considered safer and more effective than the traditional agents. Especially, DOACs offer improved long-term prevention of recurrence in patients with unprovoked VTE. The initiation of DOAC monotherapy soon after VTE onset leads to shorter hospital stays than required with the older therapies and allows for outpatient treatment. DOACs have additional benefits, such as safer anticoagulant therapy for cancer patients. These novel anticoagulants are extremely promising, but there is a current lack of evidence in areas such as dosing regimens for highly vulnerable patients and dosing for long-term use, and alternative regimens for each DOAC.