Abbott Joins Drug-Eluting Stent Fray

Originally Published MDDI November 2004

NEWSTRENDS

Abbott Joins Drug-Eluting Stent Fray

Erik Swain

Another large company is trying to enter the lucrative drug-eluting stent market, believing its technology will enable it to avoid the pitfalls of competitors.

Abbott Vascular Devices (Redwood City, CA), a division of Abbott Laboratories (Abbott Park, IL), announced in September that it has begun a clinical trial for ZoMaxx, its drug-eluting coronary stent design.

If the product makes it to market successfully, it would compete with offerings from Cordis Corp. (Miami) and Boston Scientific Corp. (Natick, MA). It could also face competition from other drug-eluting stents currently in development, including those from Guidant Corp. (St. Paul, MN), Medtronic Inc. (Minneapolis), and several smaller firms. But, Abbott officials say, with a $5-billion market at stake, there should be room for a number of products.

Abbott believes it will gain an advantage from its stent platform, the TriMaxx. “It uses a novel approach,” says David Van Meter, general manager of coronary technologies for Abbott Vascular Devices. Made from a trilayer composite of stainless steel and tantalum, the TriMaxx has extremely thin struts and a very low crossing profile. “That makes it very conformable and extremely easy to deliver,” Van Meter says. “Clinicians have been extremely impressed.”

One of the doctors enrolling patients for the trial, Robert Whitbourn of St. Vincent's Hospital in Melbourne, Australia, says that in vitro studies have shown that “the ZoMaxx stent design demonstrated excellent flexibility, contributing to a high level of deliverability. I am eager to test the device clinically.”

And it is that ease of use that Abbott is banking on to gain market share. “We believe stent performance drives market share,” Van Meter says. “That was one thing we learned from [Boston Scientific's] Taxus launch, where it took a 70% share in a few months, driven by improved deliverability.”

Unlike most of its drug-eluting-stent competitors, Abbott is using a pharmaceutical compound, ABT-578, that has not had prior FDA approval. It is a cytostatic drug that inhibits inflammation and proliferation of smooth muscle cells, preventing restenosis, or reblockage of the artery. Animal tests showed the drug, developed in-house at Abbott, to be highly lipophilic, allowing a high concentration to penetrate tissue.

Van Meter says Abbott does not expect the FDA review process to be cumbersome because of the lack of a preapproved compound. “We have had a number of extensive discussions with FDA about it,” he says. “We don't expect that to be an issue. The approval will be based on the stent.”

The product's coating, called Pharmacoat, is a unique formulation of phosphorylchorine licensed from Biocompatibles International plc (Farnham, Surrey, UK). It is biologically inert, resists clot formation, and includes a layer that allows for the elution. “Unlike some polymers recently commercialized, this type of coating has been used on hundreds of thousands of implants,” Van Meter says.

Enrollment for the first trial, to be conducted in more than 30 locations in Europe, Australia, and New Zealand, began in September. It will include 400 patients and compare ZoMaxx with Taxus over nine months. A U.S. trial is expected to follow shortly. Abbott projects European approval in 2006 but says it is too early to predict the timetable for a U.S. trial and FDA approval.

With a background in both the pharmaceutical and device industries, Abbott believes it is well positioned to develop combination products such as drug-eluting stents. It has had teams from both its drug and device operations dedicated to developing ZoMaxx.

Copyright ©2004 Medical Device & Diagnostic Industry