Intellectual Thoughts by Sanjay Panda: Abbott Dissolving Stent, Xience Product Show Promise

Abbott Dissolving Stent, Xience Product Show Promise

Abbott Laboratories' experimental heart stents may threaten the market dominance of Boston Scientific Corp. and Johnson & Johnson based on positive results from two studies released today.A new form of stent made by Abbott that dissolves in arteries after it's been implanted for about three years delivered a promising finding in its first human trial. Separately, Abbott's Xience, a permanent drug-coated stent marketed in Europe, was found superior to Boston Scientific's Taxus, the top U.S. seller, at keeping treated vessels open.
The findings, presented at a science meeting in New Orleans, position Xience at the front edge of new technology in the $5.4 billion-a-year drug-coated stent market, where devices seen as easier and safer to use are needed to help revive faltering sales. Patients getting Xience had fewer cardiac deaths, heart attacks and repeat procedures months later.
Xience patients ``were less likely to have blockages recur at eight months,'' said lead researcher Gregg Stone, director of cardiovascular research at Columbia University Medical Center, in an interview. ``What that means for the patient is better long-term outcomes without recurrent heart problems.''The results were presented at the annual meeting of the American College of Cardiology.

Stents are mesh tubes placed in arteries to keep them from re-closing after angioplasty, a procedure in which a balloon- tipped catheter is inflated to reopen a clogged blood vessel.

Coated Stents

Drug-coated stents release medicine to prevent scar-tissue formation. Boston Scientific and J&J's devices are made of polymer-covered metal and remain permanently in the vessel after the drug is gone. Bioabsorbable stents dissolve in about three years, leaving behind nothing but a healed blood vessel.

The dissolving devices are made from lactic acid molecules linked to form the stent, said John Ormiston, an investigator on the Abbott study and a researcher at Auckland City Hospital in New Zealand. Lactic acid is a chemical naturally produced when a person exercises. Other devices, including absorbable screws and stitches, are also made using lactic acid.

Sales have fallen for coated forms of the devices since European researchers last September tied them to formation of potentially deadly blood clots years after they were implanted.

The market for the devices peaked at $5.4 billion in 2006, below Wall Street's earlier expectations. The shares of Boston Scientific, based in Natick, Massachusetts, have fallen 36 percent in the past month to $15.22 as of yesterday in New York Stock Exchange composite trading. New Brunswick, New Jersey- based J&J shares are down 5 percent in the period to $60.51.

Some Skepticism

In the most recent studies, patients with the dissolving stents were followed for six months, while the Xience patients were monitored for nine months.Some doctors are skeptical about prospects for the dissolving stents.

``It's the devil you know versus the devil you don't,'' said William Maisel, a Harvard University heart specialist and chairman of a U.S. Food and Drug Administration advisory panel on heart devices, in a telephone interview. ``There's no replacing long-term follow-up.''

Positive results should help Xience gain market share in Europe, where the Abbott Park, Illinois-based company introduced it in October, said Phil Nalbone, an analyst at RBC Capital Markets Corp. in San Francisco in a March 21 note to investors. They also help lay groundwork for introduction of the device in the U.S., expected in the first half of 2008, he said.

Boston Scientific

Some analysts said a Xience advantage in the study would hurt Boston Scientific. When that company bought Guidant Corp. and Xience last year, it sold the vascular products division to Abbott and kept rights to use the technology in its own products.

As part of the agreement, though, Boston Scientific will market the Xience stent under a different name, Promus. Sales of that device may erode those of Taxus, which generates higher margins for that company, Nalbone wrote.

Boston Scientific's chief executive office, Paul LaViolette, said he sees the study as a win-win. ``There are two stents in that study, and we have them both,'' LaViolette said in a telephone interview.

Maisel's FDA advisory panel said in December that drug- coated stents, which have been on the market since 2003, could cause blood clots and fatal heart attacks years in one of every 200 patients after implantation. As a result, patients are being told by many physicians to take a blood thinner, such as Bristol-Myers Squibb Co.'s Plavix, for a year or more after they have a device implanted.

Dissolving Stents

Stents that dissolve after they've done their job have long been discussed as an option to the current use of permanent metal devices. The study announced today on Abbott's product is one of the earliest to show results.

In that study, Ormiston and Patrick Serruys of Erasmus Medical Center in Rotterdam followed 30 patients for six months and saw no blood clots. One patient needed a repeat procedure to reopen a vessel, and there were no deaths or heart attacks.

``The potential is to allow the patient's vessel to return to a more natural state without the permanent implantation of a mechanical structure,'' said James Capek, senior vice president of Abbott's vascular division, in a telephone interview.

Johnson & Johnson is working on a metal stent with a fully coating that will dissolve after the suppression drug has been delivered, leaving a bare-metal stent behind, company spokesman Chris Allman said.

Other competitors aren't convinced bioabsorbable stents will be safe.

Striking a Chord

``Some chord is struck with physicians who have the notion that the metallic implant seems unnatural and that it seems potentially desirable to have them go away,'' said Boston Scientific's LaViolette. ``It's an idea that has been interesting but always debated and always disappointing. The materials just never seem to be ideal.''Just the same, all stent manufacturers, including Boston Scientific, are pursuing bioabsorbable products, Maisel said.
``If it plays out that this is the way to go, they don't want to get caught with their pants down,'' he said. ``But they're not going to abandon developing metal stents.''


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