IMPERIAL: Eluvia stent tops Zilver PTX for PAD

SAN DIEGO – In the first randomized, head-to-head trial of drug-releasing stents for above-the-knee femoropopliteal peripheral artery disease (PAD), Boston Scientific’s polymer-coated, paclitaxel-eluting stent outperformed Cook Medical’s polymer-free, paclitaxel-coated stent.

M. Alexander Otto

The IMPERIAL trial (NCT02574481), funded and conducted by Boston Scientific, randomized 309 patients with occlusive lesions of the superficial femoral and/or proximal popliteal arteries to the polymer-coated, paclitaxel-eluting Eluvia stent and 156 to the paclitaxel-eluting Zilver PTX, which is the only drug-releasing stent approved in the United States for the indication. Total lesion length was 30-140 mm, with a mean of 83 mm; subjects had moderate to severe claudication.

At 12 months, primary patency was 86.8% (231/266) in the Eluvia group, versus 81.5% (106/130) among those randomized to Zilver PTX. About 5% of Eluvia patients (14/273) and 9% of patients in the Zilver PTX arm (12/133) had a major adverse event, defined as death within a month or target limb amputation or revascularization through 12 months. Both outcomes were statistically significant at P less than .0001. Overall, 4.5% of Eluvia patients (13/287) required target lesion revascularization, compared with 9% of Zilver PTX patients (13/145).

“These data suggest the Boston Scientific product is superior. Unless there are big differences in cost or technical aspects of the procedure, I would foresee a fairly substantial shift to” Eluvia if it’s approved, which seems likely, said interventional cardiologist David Cohen, MD, of Saint Luke’s Mid America Heart Institute, Kansas City, Mo., who comoderated the study presentation at the Transcatheter Cardiovascular Therapeutics annual meeting.

M. Alexander Otto

The different patency and revascularization rates might caused by the different way these stents deliver paclitaxel. The Zilver PTX is coated with the drug, so it’s released fairly quickly into surrounding tissues. The polymer coating on the Eluvia allows for slow release, “which is important considering that the observed peak of restenosis in the femoropopliteal arteries is at 10-12 months,” lead investigator William Gray, MD, a cardiologist at the Lankenau Heart Institute, Wynnewood, Pa., said at the meeting.

There were six cases of aneurysmal degeneration with Eluvia, but none with Zilver PTX. All six patients were patent at 1 year, without revascularization or stent thrombosis. It’s too early to know what to make of the finding. The planned 5-year follow-up should shed some light on the issue, Dr. Gray said.

At present, there’s no clear algorithm for above-the-knee PAD. Balloons and stents – both drug-releasing and bare – are all in play, and new devices are on the way. “With a head-to-head trial like this, we are staring to pare down all the noise in the market place. I think for long complicated lesions, I would be very surprised if we don’t start seeing more drug-eluting stents, because the results are so good. Drug-coated balloons are useful, but they take a little bit longer and a little more nuance,” especially when stent are used to touch up the results, he said.