Impact of Rabeprazole on APO-Dabigatran Exposure in Healthy Volunteers.

Background: Dabigatran is effective and safe for stroke prevention in patients with atrial fibrillation and for venous thromboembolism prevention and treatment. In Canada, APO-dabigatran, a generic formulation, has been approved based on a bioequivalence study, but its bioavailability in settings of reduced gastric acidity has not been examined. Methods: Treatment With APO-Dabigatran Absorption (TADA) was an open-label crossover study in 46 healthy male volunteers, comparing the absorption of APO-dabigatran (150 mg) with vs without rabeprazole. The primary outcome was the 24-hour total dabigatran exposure as measured by area under the curve (AUC) and peak concentration (Cmax). Results: Compared with no rabeprazole pretreatment, the total dabigatran AUC (geometric mean [gmean] AUC0-tz: 567.2 vs 804 ngh/mL, and gmean AUC0-∞: 609.7 vs 804) and Cmax (gmean: 64.1 vs 104.4 ng/mL) were significantly reduced with rabeprazole. The percent gmean ratios for AUC0-tz, AUC0-∞, and Cmax (with rabeprazole vs without) were 70.5% (95% confidence interval [CI]: 51.9% to 95.7%), 71.8% (95% CI: 53.1% to 96.9%), and 61.4% (95% CI: 44.1% to 85.5%), respectively. With rabeprazole, the proportions of participants with > 50% reduction in AUC0-tz, AUC0-∞, and Cmax were 32.6%, 30.4%, and 39.1%, respectively. Conclusions: When APO-dabigatran is administered with rabeprazole, the exposure to dabigatran is reduced by about 30%, which is similar to the level observed with Pradaxa when it was co-administered with a proton pump inhibitor. However, the finding that one-third of participants had a > 50% reduction in exposure is concerning, and it highlights the need for caution in patients who have, or are at risk of, reduced gastric acidity.

Contexte: Le dabigatran est une option thérapeutique sûre et efficace pour prévenir les accidents vasculaires cérébraux chez les patients atteints de fibrillation auriculaire et pour prévenir et traiter les thromboembolies veineuses. Au Canada, APO-dabigatran (une version générique) a été homologué sur la base d'une étude de bioéquivalence, mais sa biodisponibilité en contexte d'acidité gastrique réduite n'a pas été évaluée. Méthodologie: L'étude TADA ( T reatment with A PO- D abigatran A bsorption) est une étude croisée menée en mode ouvert auprès de 46 hommes volontaires en bonne santé, afin de comparer l'absorption d'APO-dabigatran (à 150 mg) avec et sans rabéprazole. Le critère d'évaluation principal était l'exposition totale sur 24 heures au dabigatran, telle que mesurée par la surface sous la courbe (SSC) et la concentration maximale (Cmax). Résultats: Par rapport à une administration sans prétraitement par rabéprazole, une réduction significative de la SSC totale du dabigatran (moyenne géométrique [MG] SSC0-tz : 567,2 par rapport à 804 ngh/ml; MG SSC0-∞ : 609,7 par rapport à 804 ngh/ml) et de la Cmax (MG : 64,1 par rapport à 104,4 ng/ml) a été observée avec la prise de rabéprazole. Les ratios des MG en pourcentage de la SSC0-tz, de la SSC0-∞, et de la Cmax (avec et sans rabéprazole) étaient de 70,5 % (intervalle de confiance [IC] à 95 % : 51,9 % à 95,7 %), 71,8 % (IC à 95 % : 53,1 % à 96,9 %) et 61,4 % (IC à 95 % : 44,1 % à 85,5 %), respectivement. Les proportions de participants chez qui une réduction de > 50 % de la SSC0-tz, de la SSC0-∞ ou de la Cmax a été notée avec l'administration du rabéprazole s'élevaient à 32,6 %, 30,4 % et 39,1 %, respectivement. Conclusions: Lors de l'administration d'APO-dabigatran en concomitance avec le rabéprazole, l'exposition au dabigatran était réduite d'environ 30 %, une valeur comparable à la réduction observée lors de l'administration de Pradaxa en concomitance avec un inhibiteur de la pompe à protons. La réduction de > 50 % de l'exposition médicamenteuse chez le tiers des participants n'en est pas moins préoccupante et démontre la nécessité de faire preuve de prudence lorsque l'acidité gastrique est réduite ou risque d'être réduite chez un patient.

Comparison of Oral Anticoagulants for Stroke Prevention in Nonvalvular Atrial Fibrillation: A Multicriteria Decision Analysis.

BACKGROUND: Decision on the most appropriate oral anticoagulation therapy for stroke prevention in patients with nonvalvular atrial fibrillation is difficult because multiple treatment options are available, and these vary in their clinical effects and relevant nonclinical characteristics. OBJECTIVES: To use a multicriteria decision analysis (MCDA) to compare the oral anticoagulants apixaban, dabigatran, edoxaban, rivaroxaban, and vitamin K antagonist (VKAs; specifically warfarin) in patients with nonvalvular atrial fibrillation. METHODS: We identified the evaluation criteria through a targeted literature review and clinical judgment. The final evaluation model included nine clinical events and four other criteria. We ranked possibly fatal clinical event criteria on the basis of the differences in risks of fatal events and the corresponding window of therapeutic opportunity, as observed in clinical trials. Clinical judgment was used to rank other criteria. Full criteria ranking was used to calculate centroid weights, which were combined with individual treatment performances to estimate the overall value score for each treatment. RESULTS: Using such an MCDA, dabigatran yielded the highest overall value, approximately 6% higher than that of the second-best treatment, apixaban. Dabigatran also had the highest first-rank probability (0.72) in the probabilistic sensitivity analysis. Rivaroxaban performed worse than the other non-VKA oral anticoagulants, but better than VKAs (with both having 0.00 first-rank probability). The results were insensitive to changes in model structure. CONCLUSIONS: When all key oral anticoagulant value criteria and their relative importance are investigated in an MCDA, dabigatran appears to rank the highest and warfarin the lowest.

A roadmap to improve the quality of atrial fibrillation management: proceedings from the fifth Atrial Fibrillation Network/European Heart Rhythm Association consensus conference.

At least 30 million people worldwide carry a diagnosis of atrial fibrillation (AF), and many more suffer from undiagnosed, subclinical, or 'silent' AF. Atrial fibrillation-related cardiovascular mortality and morbidity, including cardiovascular deaths, heart failure, stroke, and hospitalizations, remain unacceptably high, even when evidence-based therapies such as anticoagulation and rate control are used. Furthermore, it is still necessary to define how best to prevent AF, largely due to a lack of clinical measures that would allow identification of treatable causes of AF in any given patient. Hence, there are important unmet clinical and research needs in the evaluation and management of AF patients. The ensuing needs and opportunities for improving the quality of AF care were discussed during the fifth Atrial Fibrillation Network/European Heart Rhythm Association consensus conference in Nice, France, on 22 and 23 January 2015. Here, we report the outcome of this conference, with a focus on (i) learning from our 'neighbours' to improve AF care, (ii) patient-centred approaches to AF management, (iii) structured care of AF patients, (iv) improving the quality of AF treatment, and (v) personalization of AF management. This report ends with a list of priorities for research in AF patients.

Comparison of the cost-effectiveness of new oral anticoagulants for the prevention of stroke and systemic embolism in atrial fibrillation in a UK setting.

PURPOSE: Three new oral anticoagulants (NOACs) have recently become available in the United Kingdom as an alternative to warfarin in the prevention of stroke and systemic embolism in atrial fibrillation. This study examines the relative cost-effectiveness of dabigatran (BID dosing of 150 mg or 110 mg based on patient age), rivaroxaban, and apixaban from a UK payer perspective. METHODS: A previously published model that follows up patients through treatment of atrial fibrillation during a lifetime was adapted to allow comparison of the 3 NOACs and warfarin. Acute thromboembolic and bleeding events, as well as long-term consequences of stroke, intracranial hemorrhage, and acute myocardial infarction, were tracked. Relative efficacy was calculated from a formal indirect treatment comparison using data from the 3 key trials (Randomized Evaluation of Long-Term Anticoagulation Therapy, Rivaroxaban Once-daily oral direct factor Xa inhibition Compared with vitamin K antagonism for prevention of stroke and Embolism Trial in Atrial Fibrillation, and Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation) of the NOACs. Data from the rivaroxaban trial were adjusted for the difference in international normalized ratio control among warfarin patients versus the other 2 trials. Model outputs included total costs, event rates, and quality-adjusted life-years. FINDINGS: Among the patients taking NOACs, those taking dabigatran had the highest total QALYs (7.68 QALYs), followed by apixaban (7.63 QALYs) and rivaroxaban (7.47 QALYs). Patients taking dabigatran had the lowest total lifetime costs (£23,342), followed by apixaban (£24,014) and rivaroxaban (£25,220). The differences between dabigatran and apixaban were modest but consistent in sensitivity analyses, with the directionality only changing at the limits of the CIs for the relative risks of ischemic stroke or intracranial hemorrhage or when assuming that both treatment discontinuation and post-event disability rates differ by drug. IMPLICATIONS: Dabigatran was found to be economically dominant over rivaroxaban and apixaban in the UK setting. These economic findings are based on relative clinical efficacy from an indirect treatment comparison and would benefit from any data of direct comparisons of the NOACs in the future.