PATENT study shows positive results in treatment of in-stent restenosis in the femoropopliteal artery


Spectranetics announced six month interim 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. 

There is no device currently cleared or approved by the FDA to treat peripheral in-stent restenosis, which remains a major unsolved medical problem.

Total enrolment of 90 patients in this prospective, multicentre registry, was completed in December 2011 at five centres in Germany. Seventy-eight patients have been followed through six months. Interim results presented at LINC 2012 in Leipzig, Germany, indicate 76% freedom from target lesion revascularisation at six months. Notably, the freedom from target lesion revascularisation rate within the PATENT study exceeds the targeted freedom from target lesion revascularisation 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 artery disease associated with femoropopliteal artery in-stent restenosis at 30 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.

“The PATENT study shows that laser atherectomy for in-stent restenosis lesions can significantly reduce the amount of neointimal hyperplasia with promising target lesion revascularisation rates at six months. We look forward to the twelve month results,” said Jos Van Den Berg of Ospedale Regionale di Lugano, Lugano Switzerland, who presented the interim results.

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 angiographic core lab. Procedural success rate, defined as achievement of ≤ 30% final residual restenosis was 98.8%, and cumulative major adverse events (MAEs) were 2.2% from procedure through 30 days following the procedure. Patients saw significant and sustained improvement in ankle brachial index (ABI) and walking ability at 6 months.

The study population included patients with peripheral artery disease ranging from intermittent claudication to critical limb ischaemia (Rutherford class 2-5). Lesions ranged from 1cm to 25cm with average total lesion length of 12.5cm, and 93% were in the superficial femoral artery (SFA). Nearly 37% of patients had total occlusions. All patients had stents, 50% of patients were diabetics, and 35% had previously been treated for in-stent restenosis using other therapies.

The PATENT study follow-up will be completed in May 2012.

Spectranetics is also supporting a physician initiated pilot study in four centres in Europe evaluating the use of laser ablation followed by a paclitaxel-coated angioplasty balloon (PTX PTA) compared with the use of PTX PTA alone in the treatment of in-stent lesions in above-the-knee arteries. The first of 50 planned patients was recently enrolled. Spectranetics’ support of the PHOTOPAC (Photoablation followed by a paclitaxel-coated balloon to inhibit restenosis in instent femoropopliteal obstructions) trial is in the form of an unrestricted research grant.