Efficacy and Safety of Rivaroxaban, Apixaban, and Edoxaban for Nonvalvular Atrial Fibrillation Based on Blood Coagulation Activity and Drug Plasma Concentration: SETtsu and North Osaka Multicenter Direct Oral AntiCoagulant (SET DOAC) Registry

The therapeutic effects of oral anticoagulant drugs for nonvalvular atrial fibrillation (NVAF) suggest that the three factor Xa (FXa) inhibitors may have distinct safety profiles, though this is not yet fully conclusive. This study investigated the current dosing of rivaroxaban, apixaban, and edoxaban by monitoring drug plasma concentration (PC) and coagulation activity from the viewpoint of the safety. This multicenter clinical study monitored the drug PC and two coagulation biomarkers (fibrinogen and fibrin monomer complex [FMC]) at peak and trough timing in 268 outpatients taking rivaroxaban (n = 72), apixaban (n = 71), and edoxaban (n = 125) for NVAF. Doses were adjusted based on the dose-adjustment criteria of each drug. Referencing our previous study, peak drug PC remained below the cut-off level for predicting bleeding events except in eight patients (rivaroxaban, n = 3; apixaban, n = 2; edoxaban, n = 3) in whom bleeding events occurred. Among them, two (one each on rivaroxaban and edoxaban) had a peak drug PC below the cut-off level. Drug PCs widely varied from peak to trough, whereas FMC levels, reflecting thrombin activity, remained within the normal range (