August 28th, 2011
A “Straight A” Trial: Answers About Apixaban from ARISTOTLE
ESC 2011 is being held in a gigantic venue called the Exposition Center, close to Charles de Gaulle Airport. This enormous campus is the perfect place to showcase ESC, which can now boast that it’s the biggest cardiology meeting in the world. Its attendance and registration numbers surpass those of AHA and ACC. And the scientific quality of the presentations is excellent.
That is the backdrop for the presentation of ARISTOTLE, where Chris Granger unveiled results of an 18,000-plus patient megatrial of apixaban versus warfarin for stroke prevention in patients with nonvalvular atrial fibrillation. Imagine a trial with about 1000 institutions participating from 39 countries. Try to think of the logistics involved in a randomized double-dummy protocol: Each patient underwent finger-stick INR testing; and half of the test results were sham INRs, leading to dose adjustment of the placebo for warfarin.
The presentation auditorium was aptly named “Paris,” and all seats (I’m guessing at least 3000) were filled. We knew from a manufacturer press release 2 months ago that apixaban was superior to warfarin for both efficacy and safety. But we didn’t know the magnitude of the difference between the two groups. Prior to the presentation, there were more questions than answers.
Questions Answered by Today’s Presentation
- Was the time within the therapeutic range (TTR) for warfarin acceptable (defined by most clot experts as 60% or greater)? Yes. It was 62%.
- Were there any subgroups that didn’t benefit from apixaban’s improved efficacy over warfarin’s? No.
- Were there any types of major bleeding that occurred more often in the apixaban group? No.
- Did the reduction in stroke and reduction in major bleeding ultimately translate into a lower all-cause mortality rate in the apixaban group? Yes.
The ARISTOTLE investigators can be proud of the rigor with which they conducted this trial. If anyone doubted that we’ve entered a new era for stroke prevention in nonvalvular atrial fibrillation, fear no more.