Cypher Approval Marks New Era in Cardiac Intervention

Originally Published MDDI May 2003

NEWSTRENDS

Gregg Nighswonger

About 15-30% of all angioplasty patients experience restenosis within one year of the procedure. Certain radiation-based therapies have helped reduce the need for added interventions to open new blockages in these patients. Many clinicians, however, have viewed drug-eluting stents as showing the most promise for reducing restenosis. The successful development and launch of drug-eluting stents is also expected to have a significant impact on both the U.S. and global markets for stents.

On April 24 of this year, FDA approved the first drug-eluting stent for angioplasty procedures to open blocked coronary arteries. The product is the Cypher Sirolimus-Eluting Coronary Stent made by Cordis Corp. (Miami Lakes, FL). The stent incorporates a polymer coating that slowly releases the drug sirolimus, which the firm uses under a license from Wyeth Pharmaceuticals (Collegeville, PA).

Although the approval has been anticipated by industry, several versions of the device have been marketed overseas for some time. Nevertheless, the agency's decision is expected to give a significant boost to the stent market. 

According to Brian Firth, MD, PhD, vice president of medical affairs and health economics at Cordis, the firm began working on the concept late in 1995. “We knew that we had to put something on the stent to minimize the chance of reblockage. So we started looking at putting a radiation source on the stent, and we started looking at putting drugs on the stent,” he says. “In fact, we went through a list and screened approximately 800 compounds before settling on [sirolimus].”

Firth explains that one unique aspect of the drug is that it “blocks the cells from multiplying, but it doesn't kill them. So this is not an anticancer drug that kills the cells. It's actually an immunosuppressant drug that blocks the cells from dividing and multiplying, and allows them to go back to a resting state. So this is a cytostatic drug as opposed to a cytotoxic drug,” says Firth. Once implanted, the stent continues to release the drug for 30 to 45 days—long enough to stop the restenosis process, Firth says.

The Cordis stent uses coating technology developed by SurModics Inc. (Eden Prairie, MN ) to provide controlled release of its active drug. Firth says use of the SurModics coating was critical to device effectiveness. “Early on, going back 10 years or more, people tried to put various coatings on stents,” he says. “In fact, what they found was that some of these coatings caused an inflammation in the vessel wall and made matters worse rather than better when combined with the bare metal stents. So one of our first challenges was to find a polymer or polymers that are basically inert and don't cause inflammation of the vessel wall.”

The Cypher stent was released in Europe in April 2002, and is now available in nearly 60 countries around the world, including Latin America and some Asian Pacific countries. Firth says acceptance of the innovative stent has been fairly widespread. 

“From a clinical perspective, there is no question in anybody's mind over there that this is a huge breakthrough,” he says. “The issue that affects Europe particularly is their reimbursement system, which reacts very slowly to new technology. Where we have reimbursement in places like Switzerland, the uptake has been rapid and over 60% of patients are getting the Cypher stent.” 

Firth explains that reimbursement is unlikely to be a significant issue in the United States. “What we achieved in the U.S. was that Medicare agreed to pay incrementally for the drug-eluting stent. They made that decision last year and announced it on the first of August,” he says. “So Medicare will pay incrementally for drug-eluting stents, effective the date of FDA approval.” Firth emphasizes that the decision for Medicare to pay incrementally, even before FDA has approved the device, is unprecedented. 

Firth says the long-term effectiveness of the stent has also resolved some cost concerns. “They pay more up front, but there is a major reduction in follow up costs over the next six to 12 months because of fewer repeat revascularizations. Patients don't have to come back for a repeat procedure,” he adds. 

This issue was addressed in the firm's SIRIUS trial, which was a U.S. study involving one-year follow up of 1058 patients. “Dr. David Cohen from Harvard did a cost-effectiveness analysis and showed that, in hospital, the difference in cost in our clinical trial was about $2800 more in the patients who got the Cypher stent.” says Firth. “But at the end of one year, you've recouped over $2500 of that $2800. So that meant it was basically a break-even proposition for the payers. And obviously it had much more patient satisfaction and less anxiety.” 


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