US panel weighs risk of drug-coated heart stents

GAITHERSBURG, Md. Dec 8 (Reuters) A US advisory panel began hearing evidence about potential risks of drug-coated stents, the tiny tubes used to prop open arteries in millions of heart patients.

A controversy about the devices erupted this year when research showed they may cause dangerous blood clots in some patients months later. Johnson&Johnson and Boston Scientific Corp. sell drug-coated stents in the United States.

Hoping to provide guidance to doctors and patients, US Food and Drug Administration officials turned to a panel of 21 outside experts for advice on whether the device benefits outweigh the risks and if extended use of anti-clotting drugs should be recommended.

They also sought input on whether safety concerns applied equally to stents made by both companies.

Drug-coated stents were hailed as a major advance just three years ago because the drug coating cuts the chances of an artery closing again, a problem reported with about a quarter of bare-metal stents.

Now, doctors are rethinking their quick adoption of drug-coated stents because of the blood-clotting issue. Blood clots can kill and cause heart attacks.

Data so far indicate a ''small but significant'' increase in blood clots more than one year after a drug-coated stent is placed, FDA reviewer Andrew Farb told the panel. However, ''it has not been established'' if that translates to an elevated risk of having a heart attack or dying, he said.

Some panel members pressed Farb on why the clots had not been shown to increase those problems.

''One explanation could be the numbers are too small to show a difference. We're talking about relatively rare events,'' he said.

The FDA panel was scheduled to provide input yesterday about the risks when drug-coated stents are placed according to instructions on their labels.

But an estimated 60 percent or more of drug-coated stents are implanted in harder-to-treat patients who do not meet criteria for approved uses, FDA officials said. The panel will start discussing use in those patients late on Thursday and is set to give advice on that issue today.

Nearly 6 million patients worldwide have received drug-coated stents, and the market is worth nearly billion a year, according to an estimate by JP Morgan analysts.

Makers say the drug-coated versions continue to offer advantages over bare-metal alternatives.

Boston Scientific has said it found a slight increase in blood clots with its Taxus drug-coated stent but no higher rate of heart attacks or deaths.

Johnson&Johnson has said data so far show no significant difference between the risk of blood clots from its Cypher drug-coated stent compared with bare-metal versions.

Abbott Laboratories Inc. and Medtronic Inc market their versions of drug-coated stents in other countries, and are aiming for US launches as early as mid-2007.

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