Medtronic announced on 21 September 2009 that the latest findings from the ENDEAVOR IV clinical trial – a large study comparing two drug-eluting coronary stents head-to-head – demonstrate statistically and clinically significant differences in measures of safety between Medtronic’s Endeavor zotarolimus-eluting stent and Boston Scientific’s Taxus paclitaxel-eluting stent at three years of patient follow-up.
The new data, which also show no difference in efficacy between the two devices at three years, was presented at Transcatheter Cardiovascular Therapeutics (TCT) 2009, in San Francisco, US.
“The three-year results from ENDEAVOR IV conclusively demonstrate that choice of stent really does matter for patients with coronary artery disease,” said principal investigator Martin B Leon of New York-Presbyterian Hospital/Columbia University Medical Center and the Cardiovascular Research Foundation. “As interventionalists, we now have long-term outcomes data that should be critically evaluated when making treatment choices for our patients.”
Leon added: “For several years we have seen a trend toward outstanding safety with the Endeavor stent throughout the clinical program and in pooled analyses. These latest randomised data are the first to show statistically significant differences on hard clinical endpoints that clearly favor one drug-eluting stent over another at three years. Specifically, they show comparable efficacy between the Endeavor and Taxus stents in long-term follow-up, with significant safety advantages for Endeavor patients with regard to a reduction in large myocardial infarctions that are directly attributable to the significantly higher rate of very late stent thrombosis observed with the Taxus stent.”
Concerns about the consequences of the higher observed rate of very late (>1 year) stent clotting in drug-eluting versus bare metal stents have loomed since 2006 but have been allayed by large, population-based registry data that have not shown an increase in death or myocardial infarction. Endeavor IV represents the first long-term large, head-to-head drug-eluting vs. drug-eluting stent comparison to demonstrate a statistically significant increase in very late stent clotting and a corresponding significant increase in cardiac death and myocardial infarction. The Endeavor IV data show that at three years of follow-up, patients treated with Endeavor have a statistically and clinically significant 48% (p=0.004) lower risk of heart attack or cardiac death than patients treated with Taxus and a 91% (p=0.004) reduction in the risk of very late stent thrombosis.
“These are practice-changing data, demonstrating that we can only truly evaluate the safety and efficacy of drug-eluting stents over the long term. In clinical trials, as in clinical practice, events may continue to occur, and the story does not end at the timing of a study’s initial endpoint,” said the trial’s other principal investigator, David Kandzari of the Scripps Clinic in La Jolla. “At three years of follow-up, the Endeavor stent demonstrated comparable efficacy and impressive safety in this study versus the Taxus stent – a finding that was consistent across all patient populations in this study and across the entire Endeavor clinical trial programme.”
ENDEAVOR IV enrolled 1,548 patients, equally randomised to receive an Endeavor or Taxus drug-eluting stent. The primary endpoint in the study was non-inferiority on the measure of target vessel failure – a composite of cardiac death, myocardial infarction and target vessel revascularisation – at nine months.