Why the Rush to Approve Drug Coated Stents?Apr 25, 2008 | Parker Waichman LLP The new Xience heart stent out-performed the more popular Taxus heart stent in a one-year trial; however, experts disagree on whether stent science is moving too fast and doctors are concerned over the recent discovery that blood clots can form at the site of drug-coated stents long after implantation.
Stents are tiny wire-mesh tubes used to prop open arteries after doctors clear them of blockages. Some stents have a drug coating meant to keep vessels from re-clogging following balloon angioplasty procedures. Bare-metal stents tend to re-clog more often than drug-coated stents, so physicians are quick use drug-coated stents, even in those patients with complex heart disease, not the patients in whom the devices were tested.
Xience is a new stent with a new drug coating that—in a one-year clinical trial—performs better and seems safer. While some are looking to the FDA to approve the device, others argue that more testing time is needed. Manesh Patel, MD, assistant professor of cardiology at Duke University, urges caution saying, "We want a durable result with the device we use. That is the conundrum in a rapidly moving science. We have new devices that may be safer and more effective, but we need time to see how well they reduce long-term events."
Gregg W. Stone, MD, director of cardiovascular research and education at the New York Presbyterian Hospital/Columbia University's Center for Interventional Vascular Therapy, led the 1,002-patient study of the new stent and says it's already known that drug-coated—or drug-eluting—stents generally work better than bare-metal stents.
"Physicians have to use their judgment, based on what they know and on the studies that have been done, to decide whether the use of a drug-eluting stent is in the individual patient's best interest. I don't think this new stent is going to markedly change how doctors use stents. It will just convert doctors who have used earlier stents to this one because the outcomes look safer and more effective," Stone said
The new Xience stent is coated with a different drug than is used in other stents and in comparisons to the more popular Taxus stent, showed less re-clogging of the arteries and fewer heart attacks or repeat procedures over a year of follow-up. "Compared to the most widely used stent in the world, the outcomes for the new stent, in some regards, appear safer and more effective," Stone says. "We anticipate FDA approval over the next several months."
Patel continues to urge caution, "What happens next is critical," he says. "Will we have learned from the two main lessons of the past: Will doctors show restraint, and put these stents only in the type of patients who have been studied? And will we do the longer studies to show they work?"
Stone’s study and Patel’s editorial appear in the April 23/30 issue of The Journal of the American Medical Association. Abbot Vascular, maker of the Xience stent, sponsored and funded the study. Stone, a senior investigator in many clinical trials, received research support and/or honoraria from Roche Vascular and other stent manufacturers.