In the RE-LY trial, Pradaxa (dabigatran), showed the higher 150-mg twice daily dose to be superior to warfarin, reducing stroke/peripheral embolic events by 34% and the risk of hemorrhagic stroke by 74%, with comparable major bleeding rates.
In the ROCKET AF trial, Xarelto (rivaroxaban), 20 mg once daily was shown noninferior to warfarin in reducing all-cause stroke and non-central nervous system (CNS) embolism in AF patients, with a similar rate of major bleeding. However, superiority was not achieved in the primary intention-to-treat analysis, although the secondary "on-treatment" analysis did show superiority.
While it appears from first impressions that dabigatran has the edge over rivaroxaban as it showed clear superiority over warfarin in RE-LY, several experts say it isn't anywhere near cut and dried. The reasoning has been heard many times before that different drugs in different trials cannot be compared and that the only way to know for sure would be a head-to-head trial, which is very unlikely to be conducted in the near term because it is not in the interests of the companies involved. Both drugs reduced intracranial hemorrhage compared with warfarin. This is very important. With all AF patients you know there is a one in 200 to 300 chance of having an intracranial hemorrhage on warfarin. This is halved with dabigatran, and rivaroxaban showed a similar reduction in ROCKET. There were similar adverse-event rate in ROCKET AF for rivaroxaban and warfarin. But in RE-LY there was more dyspepsia and potentially more MIs with dabigatran. Dabigatran appears to have more of an issue with adverse events. One of the downside’s of dabigatran is that it causes dyspepsia in about 10% of patients, due to its low pH, and this causes patients to discontinue treatment. Patients do not like having a bellyache and they won't take a drug if that is a side effect. Doctors could be swayed by that. Doctors should want to know the potential efficacy based on risk assessment for individual patients, and the patients in ROCKET AF were moderate to high risk, whereas in RE-LY they were low to moderate risk. The once-daily dosing schedule for rivaroxaban is a big advantage over dabigatran's twice-daily regimen. Doctors know that twice-daily dosing means that adherence will be a real challenge long term, especially as patients with AF usually feel well for long periods of time. If a patient misses one dose, it may not be catastrophic but missing two doses may well be. Therefore patients will probably prefer rivaroxaban because it's a once-a-day medication. Another difference between the RE-LY and ROCKET AF trials is that RE-LY was an open-label study while ROCKET AF had a gold-standard double-blind design.
For DVT prevention in postorthopedic surgery, rivaroxaban in RECORD was shown superior to enoxaparin, the current standard of care. Dabigatran has not shown such good results in the orthopedic setting, being shown noninferior to current standard of care in two studies but failing to meet noninferiority in other trials. In Canada, both rivaroxaban and dabigatran are approved for this indication, but only rivaroxaban has gotten reimbursement.
The biggest concern that doctors and patient should talk about is that dabigatran is not reversible in the case of major bleeding, i.e. an accident or a GI bleed, whereas rivaroxaban can be reversed. So depending on your situation and discussions with your doctor I hope this helps you decide on which drug to choose.
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