Final results of PATENT study support successful use of laser atherectomy for treating patients with peripheral in-stent restenosis


Spectranetics announced on 24 January 2013 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 in the femoropopliteal artery in the leg.

Ninety patients participated in this prospective, multicentre registry, which completed enrolment in December 2011 at five centres in Germany. The study evaluated extremely complex patients who had a previously failed stent procedure to address peripheral arterial disease.

Final results presented by Thomas Zeller (Herz-Zentrum Bad Krozingen, Germany) at the Leipzig Interventional Course (LINC) 2013 in Leipzig, Germany, indicate 82% and 52% freedom from target lesion revascularisation at six 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.

In the PATENT study, per cent diameter stenosis was reduced from 87.1% to 7.5% post-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%, and Cumulative major adverse events were 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 in-stent restenosis 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 target lesion revascularisation rate seem to be significantly better compared to balloon-angioplasty, the current standard treatment of in-stent restenosis,” said Andrej Schmidt of Park Hospital, Leipzig, Germany, and principal investigator for PATENT.

Notably, the freedom from target lesion revascularisation rate within the PATENT study exceeds the targeted rate in the randomised, controlled EXCITE ISR (Excimer laser randomized controlled study for treatment of femoropopliteal in-stent restenosis) trial, a landmark study currently underway in the USA, providing confidence in the EXCITE ISR trial design.

The EXCITE ISR trial will enrol up to 353 patients with chronic peripheral arterial disease associated with femoropopliteal in-stent restenosis at up to 35 centres in the United States. Patients are randomised 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 target lesion revascularisation.  

“We are very encouraged by the PATENT results. This is a significant step forward in a compelling body of evidence that proves the safety and efficacy of laser atherectomy in treating in-stent restenosis. Successfully treating in-stent restenosis represents an inflection point in our growth trajectory. This market is more than twice as large as the worldwide atherectomy market,” said Scott Drake, CEO of Spectranetics.

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

Spectranetics is also supporting a physician-initiated pilot study at four centres in Europe evaluating the use of laser atherectomy followed by a paclitaxel-coated angioplasty balloon compared with the use of paclitaxel-coated angioplasty balloon alone in the treatment of in-stent lesions in above-the-knee arteries. Enrolment of 50 patients is expected to be completed in the first half of 2013. Spectranetics’ support of the PHOTOPAC (Photoablation followed by a paclitaxel-coated balloon to inhibit restenosis in in-stent femoropopliteal obstructions) trial is in the form of an unrestricted research grant.

“The midterm patency with laser atherectomy for in-stent restenosis 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,” said Zeller, a co-principal investigator of PHOTOPAC.