Abbott Laboratories’ experimental dissolvable heart stent is safe and working for patients in an early human clinical trial, the company said Tuesday.
The North Chicago-based medical products giant hopes the drug-coated stent, which is inserted after angioplasty to keep blocked pathways open, evolves into the next generation of medical devices for opening clogged arteries to the heart.
Unlike existing stents made of a metal mesh or drug-coated metal, Abbott’s drug-coated “bioabsorbable” stent is designed to be “fully absorbed and slowly metabolized by the coronary artery,” the company told participants at the Transcatheter Cardiovascular Therapeutics conference in Washington, D.C.
The goal of the study is to leave behind a healed vessel after the stent is absorbed, Abbott said. Although the company says more study of patient experience is needed, doctors say the development of a non-metallic stent could be important because existing devices can clutter or cloud pictures of hearts being diagnosed, even with the latest imaging technology.
Stent developers may also need to look at additional options in the wake of new studies showing that a small number of patients who receive drug-coated metal stents have developed blood clots inside the stents several months after they are put in. Clotting can increase the risk of a heart attack or stroke.
“Why have a permanent implant for a temporary problem?” asked Dr. John Ormiston, the principal investigator on the Abbott study from Auckland City Hospital in New Zealand. Ormiston has been a paid consultant to the company.
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“I think it is the next big frontier in interventional cardiology,” he said.
The absorbable stent is made of polylactic acid, which is used in other medical products such as sutures used to close wounds after surgery and also absorb into the body, researchers say. It is coated with the same drug that Abbott uses on its drug-coated metal stent, known as Xience. The stent has been approved in Europe and Abbott will submit it to U.S. regulators next year for approval in 2008.
Absorbable stents are also being studied by other companies, but Abbott and at least one leading Chicago-area researcher said the company appears to be the furthest along in developing an absorbable stent for unclogging arteries to the heart.
“It is a very appealing and attractive option,” said Dr. John Lopez, director of the catheterization laboratory at University of Chicago Hospitals. “It remains to be seen whether it has a real benefit compared to what we are doing now. Whether it becomes the next big wave or whether it is a niche approach remains to be seen, or whether it is successful at all.”
Lopez said he has been a consultant to companies developing cardiac stents but is not involved in Abbott’s heart program.
He said he has been involved in the former Guidant Corp. carotid artery stent program, which Abbott purchased earlier this year.
Abbott’s study so far involves just 30 patients who have had the absorbable stents implanted for just 30 days, but Abbott and researchers involved with the product said it seems to be safe and shows no sign of clotting or other harmful side effects so early in the clinical trial process.
“It is extremely exciting because there is no adverse events, no stent thrombosis,” Ormiston said.
“The technology seems to be working,” he said.
The bioabsorbable stent program was part of Abbott’s $4.1 billion purchase of Guidant Corp.’s vascular device business earlier this year. In that deal Abbott gained a host of stents and other devices used to unclog arteries to the heart and brain, including the drug-coated Xience stent that recently began competing in a $6 billion worldwide market dominated by Boston Scientific Corp.’s Taxus and Johnson & Johnson’s Cypher stent.
Drug-coated stents were introduced earlier this decade. They were designed to address the potential reclogging of arteries due to scar tissue from earlier metal stents.
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