Spectranetics' PATENT Results Support Laser Atherectomy to Treat Peripheral In-Stent Restenosis

January 24, 2013—Spectranetics Corporation (Colorado Springs, CO) announced final results from the PATENT (Photo-Ablation using the Turbo-Booster and Excimer Laser for In-Stent Restenosis Treatment) study evaluating the safety and efficacy of the Spectranetics peripheral laser atherectomy catheters for the treatment of in-stent restenosis (ISR) in the femoropopliteal artery in the leg. The data were presented at the LINC 2013: Leipzig Interventional Course in Leipzig, Germany, by Professor Thomas Zeller, MD, of the Herz-Zentrum Bad Krozingen, Germany. The Principal Investigator of the PATENT study is Andrej Schmidt, MD, of Park Hospital in Leipzig, Germany.

According to the company, 90 patients participated in this prospective, multicenter registry, which completed enrollment in December 2011 at five centers in Germany. The study evaluated extremely complex patients who had a previously failed stent procedure to address peripheral arterial disease. The final results indicate 82% and 52% freedom from target lesion revascularization (TLR) at 6 and 12 months, respectively. Laser atherectomy demonstrated excellent midterm primary patency of 64% as compared to 37% with balloon angioplasty primary patency as published in previous clinical registries. This is a significant improvement considering the challenging nature of these patients, the company noted in its press release.

As summarized in Spectranetics' announcement, the PATENT study shows that percent diameter stenosis was reduced from 87.1% to 7.5% after laser atherectomy and balloon angioplasty, as measured by the angiographic core lab. Procedural success rate, defined as achievement of ≤ 30% final residual restenosis, was 98.9%. The cumulative major adverse events rate was 2.2% from procedure through 30 days following the procedure. Patients saw significant and sustained improvement in ankle-brachial index and walking ability throughout the study. Laser atherectomy in ISR lesions also preserved excellent stent integrity throughout the duration of the study.

“The PATENT study demonstrates that with laser atherectomy, excellent acute results can be achieved, and the underlying stent is not damaged. The patency and TLR rate seem to be significantly better compared to balloon angioplasty, the current standard treatment of ISR,” commented Dr. Schmidt in the Spectranetics press release.

Spectranetics advised that the freedom from TLR rate within the PATENT study exceeds the targeted rate in the randomized, controlled EXCITE ISR (Excimer Laser Randomized Controlled Study for Treatment of Femoropopliteal In-Stent Restenosis) trial, which is currently underway in the United States, thereby providing confidence in the EXCITE ISR trial design. The EXCITE ISR trial will enroll up to 353 patients with chronic peripheral arterial disease associated with femoropopliteal in-stent restenosis at up to 35 centers in the United States. Patients are randomized in a 2:1 allocation to either laser atherectomy with adjunctive balloon angioplasty or balloon angioplasty alone. The study is designed to show superiority of laser atherectomy plus adjunctive balloon angioplasty for the primary efficacy endpoint of freedom from TLR.

The PATENT study population included patients with disease severity ranging from intermittent claudication to critical limb ischemia (Rutherford class 2–5). Lesions ranged from 1 cm to 25 cm with an average total lesion length of 12.3 cm, and 93% were in the superficial femoral artery. Approximately 34% of patients had total occlusions. Fifty percent of patients were diabetic, and 36% had previously been treated for in-stent restenosis using other therapies.

Spectranetics stated that it is also supporting a physician-initiated PHOTOPAC (Photoablation Followed by a Paclitaxel-Coated Balloon to Inhibit Restenosis in In-Stent Femoropopliteal Obstructions) pilot study at four centers in Europe evaluating the use of laser atherectomy followed by a paclitaxel-coated angioplasty balloon compared with the use of a paclitaxel-coated angioplasty balloon alone in the treatment of in-stent lesions in above-the-knee arteries. Enrollment of 50 patients is expected to be completed in the first half of 2013. Spectranetics' support of the PHOTOPAC trial is in the form of an unrestricted research grant.

Prof. Zeller, who is Co-Principal Investigator of PHOTOPAC, commented, “The midterm patency with laser atherectomy for ISR lesions in the PATENT study is encouraging. We look forward to additional data on the combination of debulking with laser followed by local drug delivery.”