Boston Scientific confirms small risk of blood clots forming in drug-coated stentsSep 7, 2006 | AP Boston Scientific Corp. found a slightly higher risk of blood clotting in patients implanted with its newer drug-coated stents compared with older bare-metal versions, a company spokesman said Thursday.
The medical device maker reported the finding of its own new study to the U.S. Food and Drug Administration shortly after completing an analysis in late June, and met with the agency Aug. 1 to discuss the finding, spokesman Paul Donovan said.
Its shares fell 2.3 percent in midday trading.
Boston Scientific develops and makes the stents in Maple Grove and has a stent-making plant in Ireland.
The Natick, Mass.-based company reviewed previous clinical data involving 3,500 patients to compare rates of clotting in patients with its Taxus stent and those with older stents that are not coated with drugs.
The drug coatings are intended to help prevent formation of scar tissue that can form new blockages after surgery to implant stents, which are metal-mesh tubes that prop open coronary arteries. But recent studies, including findings released Sunday at the World Cardiology Congress in Barcelona, Spain, have indicated drug-coated stents carry a higher risk of rare instances of potentially fatal blood clots.
Boston Scientific's review confirmed that a higher risk exists in Taxus, the company's top-selling product and one of just two drug-coated stents on the U.S. market. While the stents are often credited with helping prevent heart attacks and bypass surgery, the review found a statistically significant higher rate of so-called late stent thrombosis," or clotting, with Taxus in a period beginning six months after surgery compared with bare-metal stents.
"We have seen a slight increase in late stent thrombosis, which a number of studies have clearly shown to be a class effect common to drug-eluting stents," Donovan said. "The important point is we have seen no increases in heart attacks or deaths."
The results will be published once complete data are available, he said. The finding was reported in The Wall Street Journal's Thursday editions.
Nearly 6 million people worldwide now have the drug-lined versions from the two dominant drug-coated stent makers, Boston Scientific and Johnson & Johnson's Miami Lakes, Fla.-based Cordis Corp. unit.
The Journal reported J&J has said it sees no statistically significant risk of late thrombosis in Cypher.
Shares of Boston Scientific fell 40 cents to $16.87 in midday trading on the New York Stock Exchange, near the bottom of the stock's 52-week range of $15.46 to $27.82.
Shares of New Jersey-based J&J fell 53 cents to $63.39 in midday trading on the NYSE.
Some of the blood-clotting concern stems from the fact that bare-metal stents allow heart cells to naturally grow to cover the stent after surgery, providing a natural biological lining. Drug-coated versions can prevent tissue growth, which helps prevent blockages but apparently leaves exposed metal that can act as a clot magnet.