Usually when a device company begins a clinical trial of a new product its first priority is to get the device through regulatory approval and on the market as quickly as possible.

But the CEO of ev3 (Plymouth, Minnesota) told Medical Device Daily that regulatory approval of Prot g EverFlex Self-Expanding Stent System in the treatment of peripheral artery disease (PAD) is “almost a third priority” behind first improving the scientific basis for using stents in the treatment of PAD, and secondly to validate its fracture-free claim of the device.

The EverFlex stent has been available in the U.S. since February 2006 for the palliative treatment of malignant neoplasms in the biliary tree. ev3 is conducting its DURABILITY II trial under a conditional Investigational Device Exemption (IDE) from the FDA with the goal of expanding the product’s U.S. indication to include treatment of PAD.

The trial is designed to demonstrate the stent system’s long-term patency and fracture resistance in symptomatic patients with PAD in the superficial femoral and proximal popliteal arteries of the leg, according to ev3. The study will include 30 clinical trial sites across the U.S.

Jim Corbett, CEO of ev3, told Medical Device Daily that the management of PAD patients is challenging because of “inadequate scientific data to definitively help clinicians make the right decisions on these types of lesions.” In addition to the lack of high-quality data, Corbett noted a second challenge involving stent fractures in this area of treatment.

That’s why ev3 believes its EverFlex stent system could make a difference. The company advertises durability as one of the product’s key advantages over competing devices, noting that its “three weave-peaks allow stress to be distributed through more stent material” and that its “multi-step manufacturing process and careful attention to detail produces an optimal stent finish” enabling it to achieve “superior durability.”

DURABILITY II will be the first trial in the treatment of PAD to explore single-stent treatment of lesions as long as 16 centimeters and will include rigorous, five-year follow-up on stent fracture, ev3 said. It also will be the first study to follow the Performance Goal design, which was developed by VIVA Physicians and published in the March 2007 issue of Catheterization and Cardiovascular Interventions. Supported by the FDA, the design facilitates a single-arm study of bare nitinol stents in the superficial femoral and popliteal arteries, ev3 said.

Corbett said the trial would begin enrolling patients “over the next several weeks” and will enroll just under 300 patients.

Other studies in this area have treated lesions between 6 cm and 7 cm on average, Corbett said, even though these types of lesions tend to be well-over 10 cm. That’s why it’s so significant that the DURABILITY II trial will explore single-stent treatment of lesions as long as 16 centimeters, he said.

“We’re studying real, clinically-relevant lesions that can be useful to make clinical decisions,” Corbett said.

It’s also significant, Corbett added, that the trial aims to demonstrate patency at one year and fracture-resistance for five years. “We think it will be better for the patient and it will drive market-adoption of the product,” Corbett said.

Noting both the VIVA Physicians Group and the FDA’s role in the trial, Corbett was quick to express the company’s appreciation.

“We expect that DURABILITY II will not only demonstrate the value of ev3’s stent technology, but it will also be a key step in advancing the treatment of PAD,” Corbett said. “We are very grateful for the collaboration of both the VIVA Physicians Group and FDA, both of whom were instrumental in allowing this groundbreaking trial design to move forward.”

Krishna Rocha-Singh, MD, medical director, Prairie Vascular Institute (Springfield, Illinois) lead author of the Performance Goal article and co-principal investigator of DURABILITY II, also emphasized the importance of providing physicians with more high-quality data to demonstrate “optimal treatment strategy” for PAD patients.

According to the American Heart Association (Dallas), PAD affects eight million Americans and is a significant cause of both morbidity and death.

“I expect that, with its novel approach, this trial will dramatically improve our knowledge and conviction regarding how best to treat this significant and often under-served patient population,” Rocha-Singh said.

The EverFlex was designed for use in the superficial femoral artery (SAF), where PAD is often present. The company said the device encompasses a unique spiral cell geometry constructed to withstand the extreme movement of the SFA, and in bench testing has been demonstrated to be five to ten times more durable than competitive stents.

“A significant percentage of SFA disease is diffuse, and therefore it is exciting to be able to study disease up to 16 centimeters with a single, non-overlapped stent such as the EverFlex,” said Jon Matsumura, MD, Northwestern University (Chicago), co-principal investigator. “This trial will gather important data to better understand the effectiveness of minimally invasive treatments for the many patients with often disabling symptoms of claudication.”

ev3 is a global device company focused on endovascular technologies for the minimally invasive treatment of vascular diseases and disorders.