Boehringer Ingelheim GmbH Release: Asian Populations With Atrial Fibrillation (AF) Benefit From Better Stroke Prevention With Pradaxa® (dabigatran etexilate) Compared to Warfarin
Published: Sep 12, 2012
There is a vast and increasing number of Asian people living with atrial fibrillation, with over 8 million people being treated for the condition in China alone.4 In the Asia-Pacific region, it is reported that over 5.1 million people suffer a first-ever AF-related stroke each year, with this number expected to rise dramatically as the population ages.5
Regional and ethnical differences are known to account for variances in treatment responses and can ultimately affect patient outcomes.6 The sub-group analysis involved 2,782 patients with AF from ten Asian countries, which represented approximately 15% of the 18,113 patients involved within the RE-LY® trial.2,3 Key findings from the sub-group analysis included:
• Benefits were consistent across both Asian and non-Asian groups with Pradaxa® 150 mg bid showing larger risk reductions in stroke and SE compared to warfarin (rates of stroke/SE in Asia were 1.39% per year on Pradaxa® 150 mg bid, 2.50% per year on Pradaxa® 110 mg bid and as high as 3.06% per year on warfarin)
• In Asian patients, both doses of Pradaxa® (150 mg and 110 mg bid) were associated with significantly lower rates of major bleeding events compared to warfarin (2.17% per year on Pradaxa®150 mg bid, 2.22% per year on Pradaxa® 110 mg bid, and 3.82% per year on warfarin). A significant interaction (P=0.008) was seen between treatment and region when comparing Pradaxa®150 mg bid vs. warfarin in Asian patients (HR=0.57, 95% CI 0.38-0.84) with that in non-Asian patients (HR=1.00, 95% CI 0.87-1.16)
• Similarly, both doses of Pradaxa® were associated with significantly lower rates of total bleeding vs. warfarin. This benefit was even greater in Asian patients: ? For Pradaxa® 110 mg bid vs. warfarin HR=0.48, 95% CI 0.40-0.56 for Asians and HR=0.85, 95% CI 0.79-0.91 for non-Asians
? For Pradaxa® 150 mg bid vs. warfarin HR=0.60, 95% CI 0.51-0.70 for Asians and HR=0.98, 95% CI 0.91-1.04 for non-Asians; (P<0.0001 before and after age adjustment)
“The findings of this study reaffirm the efficacy and safety of dabigatran etexilate for the treatment of people living with atrial fibrillation around the world,” commented Professor Gregory Lip, Professor of cardiovascular medicine at University of Birmingham Centre for Cardiovascular Sciences, UK, on the findings. “This analysis provides doctors who are practicing in this region with further guidance and support for the use of this oral anticoagulant and the benefits that it can deliver to patients.”
The sub-analysis also highlighted that there are known variances between populations, especially when considering the time a patient is within the therapeutic range or the rates of intracranial haemorrhages. Asian patients with AF spent less time within the therapeutic range than non-Asian patients (mean 55% versus 66%). This puts Asian patients at increased risk of stroke and SE. The rate of haemorrhagic stroke on warfarin treated patients was subsequently more than two-fold higher in Asian than in non-Asian patients (HR=2.4, 95% CI 1.3-4.7; p<0.05).1 These findings may also be important for countries with a high Asian sub-population like United States of America or the United Kingdom.
The benefits of Pradaxa® now seen for the Asian population are consistent with the overall conclusions from the RE-LY®trial. Pradaxa® 150 mg bid is the only novel oral anticoagulant, study of which has shown a significant reduction of ischaemic strokes in patients with non-valvular AF compared to warfarin, offering a relative risk reduction of 25%.2,3 In RE-LY®, a PROBE trial (prospective, randomized, open-label with blinded endpoint evaluation) Pradaxa® 150 mg bid provided a 35% reduction in the overall risk of stroke and systemic embolism versus well-controlled warfarin (INR 2-3, median TTR 67%7).**2,3 Pradaxa®110 mg bid, which is indicated for certain patients, was shown to be non-inferior compared to well-controlled warfarin for the prevention of stroke and systemic embolism.2,3
In the overall trial, both doses of Pradaxa® were associated with significantly lower total, intracranial and life-threatening bleeding compared to well-controlled warfarin, and Pradaxa®110 mg bid additionally demonstrated significantly lower major bleeding versus warfarin.2,3
* RE-LY® was a PROBE trial (prospective, randomized, open-label with blinded endpoint evaluation), comparing two fixed doses of the oral direct thrombin inhibitor dabigatran etexilate (110 mg and 150 mg bid) each administered in a blinded manner, with open label warfarin.2,3
** In an intention-to-treat (ITT) analysis. The ITT analysis represents the highest standard for analysing superiority in non-inferiority trials.