Taxus Market Share Drops as Adverse Incidents Continue

It’s been a year since Boston Scientific Corp. (Natick, MA) recalled more than 96,000 coronary stents. Yet, according to published reports, some of the same problems that led to that action have persisted—even after the company modified its manufacturing process to resolve the difficulties.

Last year’s recall involved 85,000 of the company’s market-leading Taxus drug-eluting stent along with 11,000 of its bare-metal version, Express. Most of the recently reported problems involve Taxus, since drug-eluting stents are now being used in more than 80% of the 1.4 million coronary stenting procedures performed annually in the United States.

Physicians continue to report problems with removing Taxus’s catheter-delivery system following successful stent implantation. Either the balloon fails to deflate outright or it “sticks,” making removal extremely difficult or even impossible. As a result of these difficulties, several patients have had to undergo emergency coronary bypass surgery or other procedures to remove the stent-delivery system.

According to FDA, there were more than 130 adverse incidents reported between October 2004 and April 2005 involving the Taxus stent. All of these postrecall incidents involved problems related to either balloon deflation failures or “stickiness” in removing the stent-delivery system.

In response to the reported postrecall problems, Boston Scientific said it had identified and corrected the manufacturing flaw, and that the incidence of “no deflation complaints” had improved from 1 in 10,000 before the recall to 1 in 100,000 after the recall. While industry analysts agree that the incidence of adverse events has improved, they do not believe that the data support the dramatic improvement cited by the company.

Paul Donovan, Boston Scientific’s senior vice president for corporate communications, commented that “Taxus continues to perform well with few complications. More than 1 million Taxus stent systems have been implanted, and the complaint rate has been exceedingly low.” Donovan also said the company had updated its product directions “to emphasize the importance of proper technique.” As a result, said Donovan, the incidence of “stickiness” or “withdrawal resistance” had declined substantially.

FDA reportedly views the adverse incidents with Taxus as falling within the agency’s guidelines for acceptable risk, and does not anticipate any further regulatory action at this time.

Taxus was the second drug-eluting coronary stent to gain FDA approval. Introduced in March 2004, the device quickly captured 70% of the U.S. market against its only competitor, the Cypher stent from Cordis Corp. (Miami Lakes, FL), a Johnson & Johnson company.

Yet, in recent months, Taxus’s share of the U.S. market has fallen to 59%, in part because of its reported stent-delivery problems. But some falloff is also attributable to the publication of several clinical studies suggesting that the Taxus stent may not be as effective as Cypher in preventing restenosis, the reclogging of arteries following angioplasty, and life-threatening blood clots. Although the authors of those studies all cite their limitations and caution against drawing any definitive conclusions, industry analysts believe that they have created a perception among some physicians and cardiac catheterization labs that Taxus is “a bit riskier” than its rival, Cypher.

Worldwide sales of Taxus during the second quarter of this year totaled $700 million—up 7% from $652 million in the year-ago quarter. Overall sales of drug-eluting stents are slowing, but that doesn’t account for Boston Scientific’s market erosion. Indeed, while the company’s overall sales increased by 11% during the second quarter, its net income fell by 35%—largely as a result of slowing sales of Taxus.

Taxus will soon face additional pressure from Cordis, as the J&J unit resolves its manufacturing quality issues with FDA and is able to ramp-up Cypher production. Boston Scientific also has a new competitor in the $5.5 billion global market, now that Medtronic Inc. (Minneapolis) has won European approval for its Endeavor drug-eluting stent, opening access to markets in more than 40 countries around the world. Medtronic expects to begin U.S. trials with Endeavor in 2006, with market entry expected a year later.