Abbott Laboratories moved closer to joining the U.S. market for drug-coated heart stents on Thursday as an advisory panel backed the company's experimental device.
A committee of advisers to the Food and Drug Administration voted 9-1 to recommend approval of Abbott's product, called Xience, despite uncertainty about the long-term risks of blood clots. That issue has weighed heavily on the once $6-billion-a-year market for drug-coated stents.
Most of the outside experts said the Xience device appeared reasonably safe for the first year after it was implanted.
"The early safety data are reassuring. Beyond that we simply need more information," said Dr. Clyde Yancy, the panel's chairman and a Baylor University cardiologist.
The FDA usually follows panel recommendations, and Abbott has said it expects to launch Xience in the United States in the first half of 2008.
Now, Johnson & Johnson's Cypher and Boston Scientific's Taxus are the only two U.S.-approved drug-coated stents. Abbott and Medtronic , with its Endeavor stent, are seeking to join the field.
Stents are tiny mesh tubes that doctors insert to prop open arteries after clearing them of blockages. Drug coating was added to newer versions starting in 2003 to keep the vessels from reclogging.
The use of drug-coated stents has been hurt by a rare but serious risk of blood clots developing months, or more than a year, after doctors implant the devices. Blood clots may lead to heart attacks.
The blood-clot risk with Xience is unclear, several panel members said, noting the company provided limited data on 422 patients who had the Xience device implanted for two years.
"I thought the safety data in 12 to 24 months was inadequate and it was a bad precedent to establish," said Dr. John Somberg, the lone panel member to vote against Xience.
Based on the available data through two years, the rate of blood clots for Xience and Taxus was similar, about 1.3 percent using one of the standard clotting definitions. The committee urged a large post-approval study to better gauge the chances of developing a blood clot with Xience.
Committee members agreed that Abbott's studies to date showed Xience was effective at keeping arteries clear and some saw advantages over Taxus, the current market leader.
"I think (Xience) represents a step forward," said Dr. Richard Page, a panel member and cardiologist at the University of Washington School of Medicine in Seattle.
Many Wall Street analysts predict Xience will eventually become the top-selling drug-coated stent. "For 2008 in the U.S., I'm looking for about $520 million in total Xience sales," RBC Capital Markets analyst Phil Nalbone said.
That would represent about 22 percent of the drug-coated stent market in the United States and assumes a Xience launch late in the first quarter of 2008, he said.
Stanford Group managing director Jan Wald said Xience could lead the U.S. market in six months to a year and expects the stent to capture market share in excess of 25 percent.
Abbott acquired Xience from Guidant Corp when Boston Scientific bought Guidant in 2006 and divested the Guidant vascular business. As part of the deal, Boston Scientific would market Xience alongside Taxus, but would call the new product Promus and return 40 percent of gross profits from Promus to Abbott.
The panel vote was "very encouraging," Abbott Executive Vice President John Capek said in a statement. Boston Scientific also welcomed the decision. Xience already is sold in other countries.
In October, an FDA advisory panel unanimously urged approval for Medtronic's Endeavor stent. Medtronic has said it expects final FDA clearance by year end.
Abbott shares rose 70 cents, or 1.2 percent, in extended trading from their $57 official close on the New York Stock Exchange.