John Eikelboom, MD, of McMaster University discusses the 3 arms of the COMPASS trial and explains the need for it to end earlier than anticipated.
Transcript (slightly modified) What were the basic findings of the COMPASS trial and why was it stopped early?
The COMPASS trial was a 3-arm study and it tested the combination of rivaroxaban—about 2.5 mg twice a day—and aspirin; rivaroxaban alone; and aspirin alone. The winning arm in this study was the combination, which was superior to aspirin. The Data Safety Monitoring Board stopped the trial early because they found that the difference in treatment effects and the event rates were so different at the interim analysis, that it exceeded the stopping rule.
The results to summarize: the combination, compared with aspirin, reduced the primary outcome of cardiovascular death, stroke, or myocardial infarction by 24% with a consistent effect on the components of that outcome. It also reduced the outcome of mortality—so, an 18% reduction in mortality. There was a price to pay, and the price to pay was an increase in bleeding and the hazard ratio was 1.7, so there was clearly an increase in bleeding. But, reassuringly, there was no excess of the most severe bleeds.
When we look at the net benefit, the ultimate measure of net benefit is actually mortality and there was a reduction in mortality, as I’ve mentioned. There was also a reduction in a pre-specified net benefit analysis that included the primary outcome and the severe bleeds.