BIONICS: Novel DES Designed for Uniform Drug Delivery Passes 1-Year Test

Neil Osterweil

October 31, 2016

WASHINGTON, DC — So far so good: an investigational metal stent with an elastomeric polymer-coating that elutes ridaforolimus, an analog of rapamycin, was judged to be noninferior to a zotarolimus-eluting stent at 1 year in a "more-comers" population[1].

Among nearly 2000 patients with non-ST elevation MI (NSTEMI) or complex vascular lesions, the rate of target lesion failure (TLF) was an identical 5.3% in patients assigned to receive either the novel ridaforolimus-eluting stent (BioNIR, Medinol) or the zotarolimus-eluting stent (Resolute Integrity, Medtronic).

The maker of the novel stent intends to use the results from the BioNIR Ridaforolimus Eluting Coronary Stent System in Coronary Stenosis (BIONICS) trial to file for approval of the device with the US Food and Drug Administration (FDA), according to Dr David E Kandzari (Piedmont Healthcare, Atlanta, GA), who reported the phase 2  study here at TCT 2016.

"In the present large-scale, 'more-comers' trial, the BioNIR ridaforolimus-eluting stent was noninferior to the Resolute stent for the primary end point of target lesion failure at 1 year and resulted in low rates of target lesion revascularization and stent thrombosis. These findings endorse the safety and efficacy of BioNIR in patients representative of real-world clinical practice," Kandzari said in his presentation.

Laser-Cut Device

The BioNIR stent is made from an 80-µm-thin cobalt alloy and is characterized by variable strut size and width that is designed to permit more even drug distribution under variable conditions. The novel antiproliferative agent ridaforolimus used in the stent is associated with a higher therapeutic-to-toxicity margin compared with most other agents in its class, Kandzari said.

"Further, a biopermanent elastomeric polymer is resistant to blending, bonding, cracking, peeling, and distortions that have been observed with contemporary drug-eluting stents," he said.

The stents are made from a thin sheet of cobalt alloy that is laser cut, sprayed and coated with drug, then rolled into a cylinder like a cannoli shell and laser welded. This manufacturing process ostensibly allows for greater efficiencies that could translate into cost savings compared with conventionally manufactured drug-eluting metal stents, he said.

More than 95% of the ridaforolimus in the durable polymer is eluted over a 180-day period, but the drug is distributed in a more even and gradual pattern than some other stents, such as the Resolute zotarolimus-eluting stent, he said.

BioNIR Shows Its Mettle

The BIONICS investigators enrolled a total of 1919 patients with NSTEMI or complex lesions at 76 centers in the US, Canada, Europe, and Israel and randomly assigned them to receive either the ridaforolimus-eluting stent (958 patients, 1275 lesions) or zotarolimus-eluting stent (961 patients, 1277 lesions). The baseline characteristics between the groups were similar except for a higher proportion of severe calcification among patients assigned to the investigational stent (13.3% vs 10.5%, P=0.03).

In keeping with its "more" (but not "all")-comers designation, patients were excluded from the study if they had severe LV dysfunction with LVEF less than 30%, cardiogenic shock, hemodynamic instability, prior history of stent thrombosis, or inability to adhere to dual antiplatelet therapy.

The primary end point of TLF—defined as a composite of cardiac death, target vessel MI (TV-MI), and ischemia-driven target lesion revascularization (ID-TLR) was the same, at 5.3%, in each trial arm.

Cardiac death rates were 0.5% in the ridaforolimus arm vs 0.2% in the zotoralimus arm. Rates of TV-MI were 3.1% and 3.3%, respectively, and rates of ID-TLR were 3.0% and 2.4%. None of these differences were statistically significant.

There was no difference in the rate of definite or probable stent thrombosis, which occurred in 0.4% patients who received the BioNIR stent vs 0.6% of those who received the Resolute device.

In addition, there were no significant between-arm differences in a prespecified subgroup analysis of factors relevant to the presentation of acute coronary syndrome, diabetes, sex, age, or region of enrollment.

However, there was a small but statistically significant difference in device success rates between the groups, at 98.3% for the BioNIR stent vs 99.5% for the Resolute stent (P=0.004).

"A Little Disappointing"

Invited discussant Dr Stuart Spencer, executive editor of the Lancet, which sponsored the late-breaking abstract session where the data were presented, commented, "It's very interesting to see new stents coming along; I thought we weren't going to have any more, but they keep popping up, and it's wonderful how these studies—perfectly designed, well executed, wonderful follow-up, and everything seems to be as good as everything else—from a scientific point of view, it is a little disappointing.

"But from a patient point of view it's wonderful that everything we touch is doing so well," he added.

The results of this trial and the BIO-RESORT trial, also reported at the session, show that despite the use of very different stents with different designs using different antiproliferative agents, the results with PCI with stenting are uniformly very good, "so we have currently a very safe intervention," commented invited discussant Dr Stephane Cook (University of Fribourg, Switzerland).

For clinicians in the US, given a plethora of stents to choose from, the ultimate decision about which device to pick is likely to come down to cost, commented discussant Dr Stephen G Ellis (Cleveland Clinic, OH).

The study was supported by Medinol. Kandzari disclosed research funding and grant support from the company. Cook, Ellis, and Spencer reported having no relevant financial relationships.

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