Wednesday, October 19, 2005

Clinical Outcomes in ENDEAVOR III Stent Study Consistent With Previous Endeavor Trials
By Julie McKeel

David Kandzari, MD

After eight months in trial, Medtronic's Endeavor stent failed to keep heart arteries from shrinking after surgery as well as rival Johnson & Johnson's Cypher stent.

The stents are tiny wire-mesh tubes used to prop open diseased arteries after they have been surgically cleared of plaque. Medtronic's trial included 436 patients with coronary artery lesions; 323 patients received the Endeavor stent and 113 patients received the Cypher stent.

According to the results, the 436-patient Endeavor III study barely missed its main goal of equaling the Cypher stent in the measurement of vessel diameter narrowing known as "in-segment late loss."

The difference in late loss -- one predictor of whether a heart vessel will reclog -- was 0.21 millimeters, just missing the 0.20-millimeter threshold needed to equal Cypher's results.

The Medtronic device did, however, meet several important secondary safety and performance targets when compared with the Cypher model.

Kandzari noted that the device's ability to keep patients from needing repeat procedures was a more important measure of its ultimate effectiveness.

On this secondary measurement, known as "target-lesion revascularization," the Medtronic stent performed as well as the Cypher stent.

"In routine clinical practice, we don't bring patients back for late loss (vessel renarrowing), but for recurrence of clinical symptoms," Kandzari told the Reuters News Service.

In addition, the stent caused no life-threatening blood clots, a side effect known as "late-stent thrombosis."

"The study did show a significant procedure success rate in favor of Endeavor when it came to deliverability and a lower rate of in-hospital myocardial infarctions," or heart attacks, Kandzari told TheStreet.com. According to the Endeavor trial data, the Medtronic stent had a 98.1% procedure success rate, while the Cypher's success rate was 91.2%.

"In my own view, we remain in a continued evolution in our understanding of the relationship between angiographic biomarkers, so-called surrogates like late loss, and their relationship with clinical outcomes, such as target lesion revascularization [TLR]," Kandzari told theheart.org. "Of course, in real-world clinical practice, the most meaningful outcome is a clinical event, particularly the occurrence of target lesion revascularization. I think that not only in the ENDEAVOR III trial, but also in ENDEAVOR II , when we combine these data, in aggregate the occurrence of target lesion revascularization is only about 5%, which is quite favorable."

These latest results do not spell the end of the ENDEAVOR program. The ENDEAVOR IV study, an 80-center, 1548-patient trial in North America , is comparing the Endeavor stent with Boston Scientific's Taxus paclitaxel-eluting stent. The primary end point of this trial is target vessel revascularization.

Medtronic has submitted data to the Food and Drug Administration to start the approval process for the Endeavor in the U.S. The company already sells its Endeavor drug-coated stents in Europe.

Medtronic, Inc. (www.medtronic.com) is headquartered in Minneapolis.