James Jin

Edoxaban versus enoxaparin–warfarin in patients undergoing cardioversion of atrial fibrillation (ENSURE-AF): a randomised, open-label, phase 3b trial

BACKGROUND Edoxaban, an oral factor Xa inhibitor, is non-inferior for prevention of stroke and systemic embolism in patients with atrial fibrillation and is associated with less bleeding than well controlled warfarin therapy. Few safety data about edoxaban in patients undergoing electrical cardioversion are available. METHODS We did a multicentre, prospective, randomised, open-label, blinded-endpoint evaluation trial in 19 countries with 239 sites comparing edoxaban 60 mg per day with enoxaparin-warfarin in patients undergoing electrical cardioversion of non-valvular atrial fibrillation. The dose of edoxaban was reduced to 30 mg per day if one or more factors (creatinine clearance 15-50 mL/min, low bodyweight [≤60 kg], or concomitant use of P-glycoprotein inhibitors) were present. Block randomisation (block size four)-stratified by cardioversion approach (transoesophageal echocardiography [TEE] or not), anticoagulant experience, selected edoxaban dose, and region-was done through a voice-web system. The primary efficacy endpoint was a composite of stroke, systemic embolic event, myocardial infarction, and cardiovascular mortality, analysed by intention to treat. The primary safety endpoint was major and clinically relevant non-major (CRNM) bleeding in patients who received at least one dose of study drug. Follow-up was 28 days on study drug after cardioversion plus 30 days to assess safety. This trial is registered with ClinicalTrials.gov, number NCT02072434. FINDINGS Between March 25, 2014, and Oct 28, 2015, 2199 patients were enrolled and randomly assigned to receive edoxaban (n=1095) or enoxaparin-warfarin (n=1104). The mean age was 64 years (SD 10·54) and mean CHA2DS2-VASc score was 2·6 (SD 1·4). Mean time in therapeutic range on warfarin was 70·8% (SD 27·4). The primary efficacy endpoint occurred in five (<1%) patients in the edoxaban group versus 11 (1%) in the enoxaparin-warfarin group (odds ratio [OR] 0·46, 95% CI 0·12-1·43). The primary safety endpoint occurred in 16 (1%) of 1067 patients given edoxaban versus 11 (1%) of 1082 patients given enoxaparin-warfarin (OR 1·48, 95% CI 0·64-3·55). The results were independent of the TEE-guided strategy and anticoagulation status. INTERPRETATION ENSURE-AF is the largest prospective randomised clinical trial of anticoagulation for cardioversion of patients with non-valvular atrial fibrillation. Rates of major and CRNM bleeding and thromboembolism were low in the two treatment groups. FUNDING Daiichi Sankyo provided financial support for the study.

A prospective evaluation of edoxaban compared to warfarin in subjects undergoing cardioversion of atrial fibrillation: The EdoxabaN vs. warfarin in subjectS UndeRgoing cardiovErsion of Atrial Fibrillation (ENSURE-AF) study.

We designed a prospective, randomized, open-label, blinded end point evaluation parallel group Phase 3b clinical trial comparing edoxaban (a new oral factor Xa inhibitor) with enoxaparin/warfarin followed by warfarin alone in subjects undergoing planned electrical cardioversion of non-valvular atrial fibrillation. The primary efficacy end point is the composite end points of stroke, systemic embolic event, myocardial infarction, and cardiovascular (CV) mortality, from randomization until the end of follow-up (day 56 post cardioversion). The primary safety end point is the composite of major and clinically-relevant non-major bleeding, from the first administration of study drug to end of treatment (Day 28 post cardioversion) +3 days. The primary efficacy analysis will be conducted on the intention-to-treat population whereas the primary safety analysis, on the safety population. The study includes stratification on the following levels: (i) approach to cardioversion (transoesophagel echocardiography or non-transoesophagel echocardiography) as determined by the Investigator; (ii) subjects experience in taking anticoagulants at the time of randomization (anticoagulant-experienced or anticoagulant-naïve); and (iii) assigned edoxaban dose (full 60 mg QD or reduced 30 mg dose QD). A subject with one or more factors (CrCl ≥15 mL/min and ≤50 mL/min, low body weight [≤60 kg], and concomitant use of p-pg inhibitors (excluding amiodarone) will receive a reduced dose (30 mg) of edoxaban if the subject is randomized to the edoxaban group. ENSURE-AF will be the largest prospective randomised trial of anticoagulation for cardioversion, also involving a Non-VKA Oral Anticoagulant-edoxaban.

Anticoagulation Control in Warfarin-Treated Patients Undergoing Cardioversion of Atrial Fibrillation (from the Edoxaban Versus Enoxaparin–Warfarin in Patients Undergoing Cardioversion of Atrial Fibrillation Trial)

In the Edoxaban Versus Enoxaparin-Warfarin in Patients Undergoing Cardioversion of Atrial Fibrillation (ENSURE-AF) study (NCT 02072434), edoxaban was compared with enoxaparin-warfarin in 2,199 patients undergoing electrical cardioversion of nonvalvular atrial fibrillation (AF). In this multicenter prospective randomized open blinded end-point trial, we analyzed patients randomized to enoxaparin-warfarin. We determined time to achieve therapeutic range (TtTR); time in therapeutic range (TiTR); their clinical determinants; relation to sex, age, medical history, treatment, tobacco use, race risk (SAMe-TT2R2) score; and impact on primary end points (composite of stroke, systemic embolic event[SEE], myocardial infarction [MI], and cardiovascular death [CVD] and composite of major + clinically relevant nonmajor bleeding). Among 1,104 patients randomized to enoxaparin-warfarin, 27% were naïve to oral anticoagulants. Mean age was 64.2 ± 11 years and mean congestive heart failure, hypertension, age ≥75 (doubled), diabetes mellitus, prior stroke or transient ischemic attack (doubled), vascular disease, age 65-74, female (CHA2DS2-VASc) score was 2.6. Mean TtTR was 7.7 days (median 7 days) and mean TiTR after reaching an international normalized ratio of 2.0 to 3.0 was 71%. In 695 patients who had an INR <2.0 before the first dose and who reached an INR ≥2.0, 436 had a SAMe-TT2R2 score ≤2 and 259 had a score >2. On multivariate regression, an independent predictor of extended TtTR was creatinine clearance (p = 0.02). TtTR was marginally related to stroke/SEE/MI/CVD (p = 0.06; odds ratio  0.23, 95% confidence interval 0.02 to 1.17) but not to any bleeding. Independent predictors of TiTR were previous vitamin K antagonist experience (p<0.01) and low hypertension, abnormal renal or liver function, stroke, bleeding, labile INRs, age >65, concomitant drugs or alcohol (HAS-BLED) score (p = 0.02). TiTR was related to any bleeding (p = 0.02; odds ratio  0.39, 95% confidence interval 0.16 to 0.88), but not stroke/SEE/MI/CVD. In this cohort of warfarin users with a high TiTR no difference was seen between TtTR and TiTR in relation to SAMe-TT2R2 score. In conclusion, even in this short-term study, TiTR was significantly related to bleeding events.