(Investigators in the current randomized trial were limited, per the Food and Drug Administration–approved study protocol, to treat lesions that were no longer than 14 cm, Dr. Dake said.)
Dr. Hans Krankenberg of the cardiovascular center at the University of Hamburg (Germany) said that an ongoing international Zilver PTX registry is showing, thus far, that “the findings from this trial can be transferred to almost all [other lesions].”
Patients in the randomized trial had an average age of 68 years, and almost half had diabetes.
Clinical outcomes, which will be presented later, mirror the patency findings, Dr. Dake said. There will be ongoing follow-up through 5 years.
Dr. William A. Gray, director of endovascular services at Columbia University Medical Center, New York, who moderated a discussion of the study at the meeting, noted that the Zilver PTX trial followed both the SIROCCO trial, which tested a sirolimus-eluting, durable polymer–coated SMART stent against a bare-metal stent in patients with femoropopliteal disease, and the STRIDES trial, which tested an everolimus-eluting, durable polymer–coated ABSOLUTE stent. Both studies failed to show any real efficacy at reducing restenosis.
The Zilver PTX stent lacks a durable polymer and delivers paclitaxel rather than a limus drug, which raises questions about the causal mechanisms for its unprecedented success, Dr. Gray said. There are also questions about how its effectiveness in the shorter lesions in this trial can be extrapolated to real-world lesion lengths of 20 cm and even 30 cm. Nevertheless, he noted, this positive trial is a critically important proof of concept, and potentially groundbreaking in the way superficial femoral artery disease and popliteal treatment will be viewed from now on.
The Zilver PTX stent is currently available in Europe. In the United States, Cook Medical has submitted a premarket approval application to the FDA, a company spokesperson said.
The trial was sponsored by Cook Medical, which manufactures the Zilver PTX stent. Dr. Dake disclosed that he had clinical trial support from Cook Medical, consulting fees/honoraria from W.L. Gore and Abbott Vascular, and equity interest/stock options in various device companies. Dr. Gray is a consultant for Cook Medical, which manufactures the Zilver PTX stent, as well as Abbott Vascular and Cordis/Johnson and Johnson.
* Correction, Oct. 20, 2010: The original version of this article incorrectly referred to Zilver PTX as Zenith PTX on several references. This version has been updated.