Boston Scientific's Synergy Stent performs well in pivotal clinical trial

Boston Scientific's Synergy stent --Courtesy of Boston Scientific

Boston Scientific's ($BSX) Synergy bioabsorbable polymer drug-eluting stent is on track for FDA approval after the successful Evolve II pivotal clinical trial, experts said, citing data released yesterday at the American Heart Association meeting in Chicago.

The device achieved noninferiority to the company's Promus Element Plus stent, as measured by target lesion failure, a composite measure of cardiac death, heart attack caused by the treated vessel and reintervention. After 12 months, Synergy had a target lesion failure rate of 6.7% compared to 6.5% for the Promus, a statistically insignificant difference.

Wells Fargo analyst Lawrence Biegelsen said noninferiority "should be enough to drive significant adoption of the product," in a Reuters article.

In addition, the rate of stent thrombosis--the formation of a blood clot that blocks the stent--was 0.4%, and there were no definite occurrences of the adverse event 24 hours after implantation.

"The one-year data from the EVOLVE II trial, particularly the exceptionally low stent thrombosis rate, are encouraging because this is a complex patient population," said Dr. Dean Kereiakes, who medical director at The Christ Hospital Heart & Vascular Center/The Lindner Research Center in Cincinnati, OH, in the Boston Scientific release.

"This adequately supports [FDA] approval," he told Reuters, adding that the product's benefits include ease of placement during surgery and expedited healing of the target lesion.

Synergy elutes the drug everolimus. Its struts have a coating that is absorbed by the body after three months, or the amount of times that the device elutes everolimus. Abbott ($ABT) and other competitors are racing to get FDA approval for their next-generation bioresorbable stents as well.

But read carefully. Bioresorbable stents are a little different from Boston Scientific's bioabsorbable version, because, in the former, the entire device biodegrades in the body, not just the coating.

There are no bioresorbable or polymer-based bioabsorbable stents approved in the U.S. Synergy has CE-mark approval enabling sales in Europe, as do some bioresorbable stents, making the products an example of the FDA's slow pace of medical device approval, at least in the eyes of critics.

The Evolve II trial enrolled 1,684 patients in 125 sites across the world. Boston Scientific said the participants "demonstrated both clinical and angiographic complexity to a degree not observed in prior U.S. pivotal trials" for conventional drug-eluting stents.

- read the release
- here's the Reuters article

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