Drug-Eluting Stents: The Race to Market Picks Up SpeedDrug-Eluting Stents: The Race to Market Picks Up Speed
November 2, 2001
Originally Published MPMN November 2001
Drug-Eluting Stents: The Race to Market Picks Up Speed
This polymer-free stent from Cook Inc. is coated with a thin layer of the drug paclitaxel to reduce the occurrence of in-stent restenosis.
Positive clinical trial results for a drug-eluting stent from Cordis Corp. (Miami, FL; www.cordis.com) confirm the important role these devices will come to play in combating in-stent restenosis. Occurring in as many as 40% of angioplasty patients, in-stent restenosis is a serious threat to people recovering from coronary artery disease. Radiation or ultrasound procedures are typically used to prevent reblockage, but as the results of the Cordis study indicate, these treatments might soon be a thing of the past. Involving 238 patients, the randomized, double-blind trial demonstrated that a sirolimus-eluting stent completely prevented artery reclogging during a follow-up period of seven months. According to study leader Marie-Claude Morice, a zero restenosis rate has never been seen in any previous stent trial. "If confirmed," she adds, "a drastic change in the policy and strategies of revascularization will occur." This shift already seems to be in effect, however, as several other companies rush to get their drug-eluting stents to market.
STS Biopolymers (Henrietta, NY; www.stsbiopolymers. com) and B. Braun Medical (Bethlehem, PA; www.bbraun. com) are collectively developing a restenosis-preventing stent that is just beginning the FDA approval process. Incorporating STS Biopolymers' Medi-Coat drug-delivery coating, the device administers single or multiple drugs over controllable time periods ranging from days to weeks. The coating restrains the flow of liquid to ensure proper release rates and stabilizes the drug to allow sterilization. A special primer is used to permanently bond the coating to the stent. "The primer provides permanency without limiting flexibility," explains STS Biopolymers' product manager Heidi McIntosh. "The device can expand or contract, and the coating will not crack or flake."
Viewed under magnification, the microporous polyurethane coating of the stent being developed by Cardiotech International Inc. and Implant Sciences Corp. performs drug delivery and encourages tissue growth.
Currently undergoing clinical testing, a stent from Cardiotech International Inc. (Woburn, MA; www.cardiotech-inc.com) and Implant Sciences Corp. (Wakefield, MA; www.implantsciences. com) uses a microporous polyurethane coating to deliver the drug sirolimus and encourage tissue in-growth. "Our coating completely encapsulates the stent, not just the struts as is common with some devices," says Cardiotech CEO Michael Szycher. "This ensures uniform drug delivery to all the viable cells in the implant area." The microporous device incorporates holes into which endothelial cells can grow, thus speeding healing around the implant and increasing long-term blood compatibility.
A stent being developed by Cook Inc. (Bloomington, IN; www.cook-inc.com) is unique because it does not contain polymers. A proprietary process attaches a thin coating of the drug paclitaxel directly to the surface of this device. "Drug-eluting stents with polymer coatings sometimes suffer from bioreactivity issues," says spokesman David McCarty. "Since our device is metal, these concerns are eliminated." The company expects CE approval for one of its devices by the third quarter of 2002. American models are still being tested.
Other companies developing drug-eluting stents include Boston Scientific Corp. (Natick, MA; www.bsci.com) and Angiotech Pharmaceuticals Inc. (Vancouver; www. angiotech.com).
Copyright ©2001 Medical Product Manufacturing News
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