Patients suffering from irregular heartbeats (atrial fibrillation) have long had to rely on warfarin for effective anticoagulant treatment, which is notorious for being a tough drug. It not only increases the risk of internal bleeding and causes other side effects, but patients are also required to follow strict diet restrictions and have regular blood-test checks.
This all might change soon though following the findings of the ARISTOTLE trial, which were presented at the European Society of Cardiologists meeting in Paris, France, and simultaneously published in the New England Journal of Medicine.
The study, which was led by the Duke Clinical Research Institute’s Christopher Granger, conducted trials in which the patients were treated with either warfarin or the study drug, apixaban.
Over 18,000 patients were enrolled for the trials at 1034 sites in 39 countries. These patients had atrial fibrillation and at least one risk factor for stroke including heart attack, previous stroke, high blood pressure, diabetes, or heart failure.
Randomized trials were conducted between December 2006 and April 2010, where a double blind double-dummy design was used to provide either a daily 5mg apixaban treatment or dose-adjusted warfarin. The progress of the patients was then followed for 1.8 years on average.
The results of the study conclusively showed that apixaban was superior to warfarin in the trials, which has thus far been considered the ‘gold standard’ in antithrombotic treatment. Patients on apixaban were found to be 21 percent less likely to have a stroke, 31 percent had a lower risk of major bleeding, and 11 percent had a lower risk of death when compared with patients on warfarin.
Apixaban was also found to be easier to take. Patients on warfarin are required to avoid foods rich in vitamin-K and have their blood monitored and doses adjusted frequently to lower the risk of bleeding complications, a regimen which leads to many patients choosing to go without any effective therapy. Such restrictions did not apply for those taking apixaban during the trials.
No unexpected side effects were found from apixaban use. Furthermore, patients on this study drug were found less likely to discontinue use than patients who were given warfarin.
Alongside the ARISTOTLE trials, two other anticoagulants have also been recently tested and compared with warfarin in randomized trials and found to equally effective in reducing strokes. However, apixaban has been associated with a lower rate of bleeding as well as a lower rate of strokes.
Apixaban is therefore being looked upon as having the potential to revolutionize the treatment of atrial fibrillation, a condition that is becoming more common due to the aging of the population all around the world. Lifestyle factors, particulary stress, are also causing this condition to become more common among younger people.