Late-breaking clinical trials

Background: The Zilver® PTX® stent with polymer-free paclitaxel coating is the first drug-eluting stent approved (currently CE marked, investigational in the United States and Japan) for the superficial femoral artery (SFA). This multicenter, multinational, prospective, randomized trial compared the safety and effectiveness of the Zilver PTX study to balloon angioplasty (PTA) and bare metal stenting (BMS). Methods: Symptomatic patients with SFA lesions (de novo or non-instent restenosis) were randomized to PTA or Zilver PTX stent placement. PTA patients experiencing acute failure (e.g. 30% residual stenosis) underwent secondary randomization to provisional stenting with Zilver BMS or Zilver PTX. Follow-up included event-free survival (EFS), and primary patency by Duplex ultrasound core laboratory analysis (peak systolic velocity ratio 2.0). Results: 479 patients were enrolled at 55 institutions in the United States, Japan and Germany, with 241 patients randomized to the Zilver PTX group and 238 to the PTA group. Demographics and lesion characteristics (e.g., lesion length 66 mm and 63 mm, respectively) were similar for the groups. Approximately half the PTA group experienced acute failure and underwent secondary randomization; 59 and 61 patients were assigned to provisional stenting with Zilver BMS and Zilver PTX, respectively. The study results met the 12-month primary endpoint goals showing non-inferior EFS (90.4% versus 82.6%, p 0.01) and superior primary patency (83.1% and 32.8%, p 0.01) for the Zilver PTX compared to PTA. The randomized comparison of provisional stenting with Zilver PTX versus Zilver BMS also showed significant paclitaxel coating benefit, with 12-month patency rates of 89.9% and 73.0% respectively (p 0.01). Currently, 24-month follow-up is available for 278 patients, showing an 86.6% EFS rate and a 74.8% patency rate. The randomized comparison of provisional stenting with Zilver PTX versus Zilver BMS continues to demonstrate significant paclitaxel coating benefit at 24 months, with patency rates of 81.2% and 62.7% respectively (p 0.01). Conclusion: The results of this randomized, multicenter study support the safety and effectiveness of the Zilver PTX Drug-Eluting Peripheral Stent.