Medtronic Inc. (NYSE:MDT) said Friday a pivotal clinical trial testing its experimental Endurant stent showed promising results for treating abdominal aortic aneurysms after one year.
The Fridley, Minn.-based company said results from the study of 150 patients across the United States also proved Endurant is safe and effective after 30 days.
“The device has met its goals,” Tony Semedo, vice president and general manager of the endovascular innovations division at Medtronic, said in an interview.
The company has filed for pre-market approval from the Food & Drug Administration.
Medtronic estimates the global market for devices to treat abdominal and thoracic aortic aneurysms at $1.1 billion, with the U.S. comprising $700 million to $800 million of that amount. Abdominal aneurysms make up about 75 percent of the market.
Earlier this month, Medtronic received FDA approval for its Talent Captiva stent to treat thoracic aneurysms.
About 1.2 million Americans suffer from abdominal aneurysms, in which the main vessel supplying blood to the lower half of the body abnormally expands outwards and can burst. Once the sac raptures, there is an 85 percent risk of death. Treatments range from drugs to risky open-chest surgery.
Medical device makers have been trying to develop a minimally invasive therapy in which doctors use a stent to prop open the vessel, creating a new path for blood to flow. That eases pressure on the bulge, reducing the risk that it will burst.
In May, the New England Journal of Medicine published results from two major European clinical trials that suggested such stents lose their effectiveness in the long term.
While the studies reported fewer people died from abdominal aneurysms with the stents than with open surgery in 30 days, “over time this benefit disappears, with patients having equivalent long-term survival with both interventions,” the publication reported. “Among patients undergoing endovascular repair, the early advantage in mortality is short-lived, with the curves merging within 2 years.”
However, Semedo of Medtronic noted the European studies enrolled their patients a decade ago. Since then, medical device makers have “made significant design improvements,” including better durability, which improves the stent’s ability to withstand movement, he said. The technology also now minimizes blood leaks and allows doctors to implant the devices in patients with more challenging anatomies.
In addition, doctors have become more skilled at both selecting patients for the trials and performing the actual procedures, Semedo said.
“We would expect to see improved performance in the long term,” Semedo said. Medtronic’s study will take five years.
One question is whether stents are more cost-effective than surgery. One of the European studies indicated endovascular repair cost an additional $4,568 per patient.
“Although ultimately endovascular repair may be more expensive than open repair, the extent of this difference and how the two will fare in a true cost-effective analysis are not clear,” the NJAM reported.
“In an era of comparative effectiveness, further evaluation will be essential.”
One result Medtronic hopes to show in its study is that patients receiving stents require less followup treatment than surgery, which reduces costs over the long term, Semedo said.