Cook Medical's 2-Year Zilver PTX Trial Results Presented at ISET

January 17, 2011—Cook Medical (Bloomington, IN) announced that principal investigator Michael Dake, MD, presented 2-year results of the Zilver PTX trial at the International Symposium on Endovascular Therapy (ISET) in Miami Beach, Florida.

The Zilver PTX trial is a multicenter, prospective, randomized study that is composed of 479 patients who were treated at 55 institutions to evaluate Cook Medical's self-expanding Zilver PTX paclitaxel-coated nitinol stent in treating peripheral arterial disease in the superficial femoral artery. Dr. Dake reported that the investigational device showed sustained primary patency at 2 years compared to data collected at 1 year in the trial. The data for the 278 patients in the Zilver PTX cohort showed a sustained rate of primary patency. At 2 years, the device resulted in a primary patency rate of 74.8% versus a 1-year rate of 83.1%.

As detailed at ISET, the Zilver PTX device also achieved an 86.6% event-free survival rate at 2 years. Adverse events that did occur primarily involved the need to undergo another procedure to open the original blockage, worsening symptoms of peripheral arterial disease, and one amputation. No patient deaths were related to the study device or procedure. In the provisional stenting group at 2 years, 81.2% of arteries that were treated with drug-coated stents remained opened versus 62.7% of arteries that were treated with bare-metal stents.

Patients in the trial were randomized to receive either the Zilver PTX stent or angioplasty alone to open blocked superficial femoral arteries. Patients who received angioplasty that did not succeed in initially opening the artery were then randomized to a provisional group to receive either paclitaxel-coated or bare-metal stents. Approximately 50% of the patients were treated with the Zilver PTX stent, 25% were treated with angioplasty alone, 12.5% were treated with angioplasty plus a provisional bare-metal stent, and 12.5% were treated with angioplasty plus a provisional Zilver PTX stent. 

“There’s evidence of a significant drug effect even at 2 years, with a much higher rate of the arteries remaining open than with angioplasty alone or with bare-metal stents,” commented Dr. Dake. “We have not had long-term problems with late thrombosis or aneurysm, which also suggests the results are safe and durable.”

Cook Medical is conducting the trial to support a premarket approval application for marketing clearance from the US Food and Drug Administration. The Zilver PTX drug-eluting stent is an investigational device and is not approved for sale in the United States.

Dr. Dake presented the 1-year Zilver PTX data on September 24, 2010 at the Transcatheter Cardiovascular Therapeutics scientific symposium in Washington, DC. Click here for the Endovascular Today coverage of the 1-year data presentation. According to Cook Medical, the Zilver PTX trial is complemented by the Zilver PTX Global Registry, which is a global, single-arm registry involving 787 patients, including diabetic patients, symptomatic patients, and patients with complex lesions. On May 7, 2010, William A. Gray, MD, presented the interim 2-year results from the Zilver PTX Global Registry at the Society for Cardiovascular Angiography and Interventions scientific sessions in San Diego, California. Click here to read the Endovascular Today coverage of Dr. Gray’s presentation. Dr. Dake, Gary M. Ansel, MD, and Anthony O. Ragheb, MD, published an in-depth discussion on the trial design and previous results with the Zilver PTX stent in the March 2010 issue of Endovascular Today (2010;9:52–57). Click here to read the article.