Studies in two major medical journals released Tuesday suggest that Johnson & Johnson’s heart stent works better than a rival device by Boston Scientific Corp. at keeping blood flowing through diseased heart arteries.
While studies give the nod to the J&J device’s efficacy, doctors noted that J&J continues to struggle with manufacturing constraints that limit the treatment’s availability.
In a study released Tuesday in the Journal of the American Medical Association, researchers sifted through a raft of trial data pitting Johnson & Johnson’s Cypher stent, coated with the drug sirolimus, against Boston Scientific’s Taxus device that gives off the drug paclitaxel.
The drugs are supposed to prevent the tiny wire mesh tubes from reclogging after they have been inserted into an artery narrowed by heart disease.
The JAMA study used a statistical approach called meta-analysis to combine findings from six clinical trials involving 3,669 patients with the goal of assessing the safety and effectiveness of both treatments.
It concluded that J&J’s device was superior at preventing the build-up of scar tissue in arteries treated with stents that frequently sent patients back for a repeat procedure. The risk of death and heart attack was about the same with both devices, the JAMA authors found.
A spokesman for Boston Scientific said the JAMA analysis relied on a partial selection of existing data, while the best comparison of Cypher vs. Taxus, a J&J-sponsored trial dubbed Reality, demonstrated comparable levels of reclogging.
Prevention of scar tissue
The JAMA study’s release coincided with a pair of studies to be published in the upcoming edition of The New England Journal of Medicine and released on Tuesday.
Those studies, which also compared the two stents, found that J&J’s device tends to remain clearer longer than a rival brand by Boston Scientific.
In an editorial in The New England Journal of Medicine, David J. Moliterno of the University of Kentucky said if the new findings are added to conclusions from four other head-to-head tests released this year, it becomes clear that people with the sirolimus stents are less likely to need additional treatment.
On the other hand, he said, Boston Scientific’s ”paclitaxel-eluting stent holds an edge on availability, deliverability, and cost.”
The largest of the two studies, conducted by Swiss doctors, found that 6.2 percent of the 503 Cypher recipients had a heart attack, died of heart disease, or needed further treatment to reopen the blood vessel within the first nine months after receiving their stent.
The rate was 10.8 percent among the 509 Taxus recipients.
In the second study, German doctors looked exclusively at diabetics, who face a higher risk of complications from stenting procedures.
They found that heart disease had narrowed the Taxus stents by at least 50 percent in 16.5 percent of 125 patients who had the devices for nine months. The rate was only 6.9 percent among the 125 volunteers who got the Cypher stents.
Moliterno said comparative tests on the next generation of drug-releasing stents, “with various stent struts, polymers, and drugs is already well under way.”
After the two NEJM studies were presented at a cardiology meeting in March, J&J’s Cypher was able to gain market share and now commands about 40 percent of the market, up from about one-third at the start of the year.
But Dr. Samin Sharma, an interventional cardiologist at Mt. Sinai Medical Center in New York, said Cypher’s ability to grow market share has been limited by manufacturing constraints at the company.
“One of the biggest limits is the inability of J&J to manufacture enough stents to meet their demand. This is the classical case where the science speaks for a better product, but the product is not available all over,” Sharma said.
A spokesman for J&J’s Cordis unit said the company is meeting current demand for the Cypher stent and expects to be able to supply 50 percent of the market by next year. The company is working with the U.S. Food and Drug Administration to resolve internal process issues identified by the agency that relate to the manufacture of the stent.
“We are ramping up to meet growing demand,” Cordis spokesman Chris Allman said.