Medtronic Inc. (Minneapolis) was expected to make a big splash at this month's Transcatheter Cardiovascular Therapeutics (TCT) scientific symposium in Washington, DC, where the company presented results from its Endeavor III U.S. clinical trial. Favorable results were expected to help speed U.S. market entry for Endeavor, the company's first drug-eluting coronary stent.

Instead, results presented at TCT indicated that Endeavor had failed to meet Medtronic's primary goal, which was to demonstrate in-segment late loss that was “noninferior” to the performance of the Cypher drug-eluting stent by Cordis Corp. (Miami Lakes, FL), a Johnson & Johnson company. Late loss refers to the difference in the width of a vessel immediately following stenting versus that found six to nine months later. In the study presented at TCT, the Endeavor stent missed its goal by just 0.01 mm.

Medtronic's Ward: A near miss.

“We narrowly missed,” said Scott Ward, president of Medtronic Vascular (Santa Rosa, CA). Endeavor's in-segment late loss after eight months was 0.34 mm compared to 0.13 mm for the Cypher stent. To demonstrate noninferiority, Endeavor's late-loss figure had to be no more than 0.20 mm greater than Cypher's, or 0.33 mm.

However, Ward noted that in some other categories of the study, such as poststenting lesion revascularization and adverse cardiac events, Endeavor was clinically equivalent to Cypher. Adverse cardiac events include the need for repeat procedures, heart attack, and death.

In the latest clinical trial, the rates of poststenting lesion revascularization and adverse cardiac events for Endeavor were 6.3% and 7.6%, respectively, compared to 3.5% and 7.1% for Cypher. The differences are not considered statistically significant. However, a significant difference was found in the success rate for stent implantation, with Endeavor at 98.1% compared to 91.2% for Cypher.