Recent information suggesting a small but significant increase in the rate of death and heart attack possibly due to stent thrombosis in patients treated with drug-eluting stents (DES) has prompted the US Food and Drug Administration (FDA) to state that a more formal evaluation of this information

(See also items above UK consortium wins funding for regnerative stent and Drug-eluting stents come under spotlight.)

The FDA will convene a public meeting of the Circulatory System Devices Advisory Panel by the end of the year in an effort to examine all the issues.

The specific studies that have prompted the recent media inquiries are the Basket-Late study (presented at the American College of Cardiology Scientific Sessions in Atlanta, Georgia in March 2006) and more recently, the Camenzind meta-analysis (presented at the European Society of Cardiology Annual Meeting/World Congress of Cardiology Meeting in Barcelona, Spain in September 2006). The small but significant increase in the rate of death and myocardial infarction observed in these studies was noted in patients followed 18 months to three years after stent implantation.

The only two drug-coated stents currently approved for sale in the USA are Boston Scientific's Taxus and Johnson & Johnson's Cypher. Medtronic Inc and Abbott Laboratories have devices in the approval pipeline. Over the past several months, the agency has met with both manufacturers to discuss any information they have that may be pertinent to this issue.

In assessing the risk of stent thrombosis, the agency said it remains keenly interested in the long-term follow-up of patients enrolled in the original pivotal DES randomized trials as well as those in the more complex patient and lesion subsets. These include, for example, patients with diabetes, acute myocardial infarction or multiple vessel disease, or lesions involving arterial bifurcations, the left main coronary artery and long arterial segments, who are currently being treated in randomized and registry studies.

Also, the FDA is continuing to evaluate information related to the duration of treatment with clopidogrel (Plavix), a drug used in combination with aspirin to reduce or to prevent clotting in DES patients.

The situation at the moment is that the FDA believes that coronary drug-eluting stents remain safe and effective when used for the FDA-approved indications.

These devices have significantly reduced the need for a second surgery to treat restenosis for thousands of patients each year.

For further information, go to the FDA's website: www.fda.gov/cdrh.

In related news, US financial analysts are reflecting the doubts about coated stents. They are revising their views of the expected impact of drug-coated stents on the stent market, according to recent press reports.

For example, Merrill Lynch lowered its 2007 sales projections for the devices after it had carried out a survey showing that doctors were worried about the possibility of a higher risk of blood clots caused by the drug-coated stents when compared with the bare metal stents.