Originally Published MDDI December 2004
Originally Published MDDI December 2004
Drug-Eluting Stents Show Effectiveness in High-Risk Patients
|The Cypher sirolimus-eluting coronary stent emits drugs inside an artery, preventing restenosis in high- risk patients.|
A number of studies show that drug-eluting stents may be beneficial to certain high-risk patients. These findings could ultimately further expand the market for the blockbuster technology. Drug-eluting stents have already been shown to prevent restenosis over several years.
The studies were presented at the Cardiology Research Foundation's Transcatheter Cardiovascular Therapeutics conference in September. They offer good news for Johnson & Johnson's Cordis Corp. (Miami) and Boston Scientific Corp. (Natick, MA), the two makers of the drug-eluting stents currently on the market.
A South Korean study found that drug-eluting stents have performed well in patients with long lesions, who are at high risk for restenosis. Results showed that drug-eluting stents outperformed bare-metal stents, and J&J's Cypher stent outperformed Boston Scientific's Taxus. The study, from the ASAN Medical Center in Seoul, is the first to focus exclusively on those patients. It was not organized or funded by any manufacturer.
“This study is important because it shows how drug-eluting stents are performing over the long term with challenging patients,” said principal investigator Seung-Jung Park, ASAN's chief of interventional cardiology. He said this is an important and growing patient population.
Brian Firth, Cordis's vice president for medical affairs and health economics, says the study could indicate that “we have the right drug and the right release polymer. We know that pretty much all stents by themselves have the same restenosis rate.” Firth says that mechanically the Cypher stent is consistently reducing late loss more effectively than Taxus. Late loss is a measure of tissue growth inside the stent. A lower rate of late loss correlates to a lesser chance of adverse events occurring.
In another independent study, researchers at Hospital Clinicos San Carlos in Madrid, Spain, found that Cypher reduced late loss in diabetic patients 88% better than bare-metal stents. Diabetics are another patient population considered difficult to treat with stents. These patients are more likely than the average patient to have inflammation as a result of stenting. “The default treatment for diabetics has been bypass surgery, because they are thought not to do well with angioplasty,” Firth says.
He says these studies might further accelerate the shift from surgery to stenting. “Cypher works extremely well across all subgroups,” he notes.
For its part, Boston Scientific announced successful two- and three-year follow-up results from its earliest Taxus trials. The continued success indicates that Taxus likely prevents in-stent restenosis and doesn't just delay it, the company says.
“The results we are seeing mean that the achievements in the clinical trial are being duplicated in the real world,” says Eric Simso, Boston Scientific's vice president of stent marketing. “It tells us that the way we release paclitaxel holds back [restenosis]. That gives us more confidence to say that this just works, and let's now focus on what happens with high-risk patients.”
As for the results touted by J&J, Simso says it is too early to draw conclusions other than that stenting “is not a disaster” in those high-risk patients.
The new findings won't immediately lead to expanded indications in the United States. Those can only come with new, company-sponsored randomized clinical trials. But they might lead to elimination of some contraindications in other countries. These results might also encourage doctors to try stenting on patients not previously considered for it.
Some firms hoping to compete with J&J and Boston Scientific also announced encouraging results at the conference. Guidant Corp. (Indianapolis) reported that late loss for its drug-eluting stent was 0.10 mm after six months, compared with 0.84 mm for a bare-metal stent. The results come from a 60-patient prospective trial. A pivotal trial is scheduled to begin in the first quarter of 2005. Conor Medsystems Inc. (Menlo Park, CA) reported that its paclitaxel-eluting cobalt chromium stent showed an in-stent restenosis rate of 1.9% and a target lesion revascularization rate of 1.8% after four months. Other potential players in the market include Medtronic Inc. (Minneapolis) and Abbott Vascular Devices (Redwood City, CA).
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