November 7th, 2010
RE-LY Substudy Finds Dabigatran Effective in Secondary Stroke Prevention
A substudy of the RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial demonstrates that dabigatran is as effective in AF patients for secondary stroke prevention as it is for overall stroke prevention. In their paper in the Lancet Neurology, Hans-Christoph Diener and the RE-LY study group report the results of the trial in the predefined subset of more than 3600 AF patients who had had a previous stroke or TIA.
The rate of stroke or systemic embolism was similar in all three groups (2.78% for warfarin, 2.32% for 110 mg dabigatran, 2.07% for 150 mg dabigatran). Compared to the warfarin group, the rate of major bleeding was lower in the low-dose dabigatran group (RR 0.66) and the same in the high-dose dabigatran group (RR 1.01). Intracranial bleeding was significantly lower in both dabigatran groups when compared to the warfarin group, prompting the authors to raise the possibility that dabigatran doesn’t cross the blood-brain barrier.
Compared to the warfarin group, net clinical benefit (defined as the composite of stroke, systemic embolism, pulmonary embolism, MI, death, or major hemorrhage) was marginally lower in the low-dose dabigatran group (RR 0.81) but not the high-dose dabigatran group (RR 1.01). In an accompanying comment, Deirdre Lane and Gregory Lip write that, based on this analysis, “110 mg dabigatran might be the preferred treatment option in patients who have had a previous stroke or transient ischaemic attack.” They note, however, that the paper does not include head-to-head comparisons of the safety and efficacy of the 2 doses of dabigatran and recommend that physicians talk with their patients “regarding their preferences for treatment dose… to ascertain their threshold for stroke prevention over increased bleeding risk or vice versa.” (It should be noted that the FDA recently approved the 150 mg dose of dabigatran, but not the 110 mg dose.)
For more of our coverage on dabigatran, check out the Dabigatran Resource Round-Up.