Results from a sub-group analysis of the randomized evaluation of long-term anticoagulation therapy, warfarin, compared with dabigatran (RE-LY®) study – the largest atrial fibrillation outcomes trial ever completed, with 18,113 patients across 44 countries – have been published in The Lancet.

The subgroup analysis assessed the effects of centre-based international normalized ratio (INR) control on study outcomes.

‘These findings support the superiority of 150mg dabigatran twice daily and the non-inferiority of 110mg dabigatran twice daily versus warfarin for protection against stroke in atrial fibrillation irrespective of the quality of INR control that a centre can achieve,’ said Professor Lars Wallentin, Professor of Cardiology and Director of the Uppsala University, Sweden.

‘For secondary outcomes, such as non-haemorrhagic events and mortality, advantages of dabigatran were reported for sites with poorer INR control, whereas results were comparable in sites with better INR control. Overall, these results show that local standards of care affect the benefits of switching to new treatment alternatives.’

The study demonstrated that dabigatran etexilate 150mg BID was superior to warfarin in the reduction of stroke and systemic embolism, independent of the level of centre-based INR control.

Dabigatran etexilate 110mg BID was similar to warfarin in the reduction of stroke and systemic embolism with lower rates of major bleeding, independent of the level of centre-based INR control, and both dosages of dabigatran etexilate were superior to warfarin in terms of intracranial haemorrhage, irrespective of centre-based INR control.

Up to three million people worldwide suffer strokes related to atrial fibrillation each year. In contrast to vitamin-K antagonists, which variably act via different coagulation factors, dabigatran etexilate provides predictable anticoagulation with a low potential for drug–drug interactions and no drug–food interactions.

The registration process for dabigatran etexilate is underway in Europe (including the UK), Japan and other countries. The company hopes to receive a marketing authorization for dabigatran etexilate in first countries by the end of 2010.

Further reading

Wallentin, L. et al. Efficacy and safety of dabigatran compared with warfarin at different levels of international normalised ratio control for stroke prevention in atrial fibrillation: an analysis of the RE-LY trial. The Lancet (in press)
Lin, H.J. et al. (1996) Stroke severity in atrial fibrillation: the Framingham study. Stroke 27, 1760–1764