LONDON, Sept 14 (Reuters) Johnson&Johnson's Cypher drug-coated stent is less likely to cause late stent thrombosis or heart attacks than Boston Scientific's rival product Taxus or bare-metal stents, Swiss researchers said today.
The findings from a large pooled, or meta- analysis of clinical trials may help physicians decide how best to use the controversial drug-covered scaffolds that prop open clogged coronary arteries, the team said.
J&J said the data was compelling but Boston Scientific argued it was flawed.
The independent analysis, involving records from more than 18,000 patients, found no difference in overall mortality risks, either between the two types of drug stents or bare-metal ones.
But the risk of late stent thrombosis -- potentially fatal blood clots inside the devices occurring 30 days or more after implantation -- was more than twice as high in patients given Taxus rather than bare stents, and 85 per cent higher for Taxus versus Cypher.
The study showed the Cypher stent carried a 19 per cent lower risk of heart attack compared to bare ones and a 17 percent lower risk compared to Taxus.
''We conclude, therefore, that siromilus-eluting (Cypher) stents seem to be clinically better than bare-metal and paclitaxel-eluting (Taxus) stents,'' the Swiss research group wrote in the Lancet medical journal.
Cypher and Taxus are the only drug stents currently approved by the US Food and Drug Administration but others, including Medtronic's Endeavor and Abbott's Xience V, are available in Europe and targeted for a 2008 US launch.
FALLING SALES Initially drug stents were enthusiastically embraced by doctors, because of their ability to prevent arteries renarrowing, as often happens with bare ones.
Their use has fallen sharply in the past year, however, due to fears about late stent thrombosis and analysts expect worldwide sales this year to be down around 1 billion dollars, or one fifth, on 2006 levels.
Cordis, the J&J unit responsible for Cypher, said the Swiss data constituted the largest and most robust set of data yet published in a peer-reviewed journal, and provided clarity as to the differences between Cypher and Taxus.
But Boston Scientific said the methodology behind the attempt to compare the two devices indirectly was flawed and did not take into account differing patient groups between trials, as well as important variations among bare stents.
The big difference in stent thrombosis rates claimed between the rival products was also not backed up by real world experience, which showed they both had comparable levels of efficacy and safety, it said.
Peter Juni of the Institute of Social and Preventive Medicine at the University of Berne, one of the study authors, acknowledged his team's network meta-analysis was unusual.
''We used novel statistical methodology, which is not that easily understood by physicians involved in routine care of patients, and because of that there might still be a debate,'' he said in a telephone interview.
Nonetheless, Mark Webster and John Ormiston of Auckland City Hospital, New Zealand, wrote in a Lancet commentary that the study was the best current comparison of the two drug stents.
The Swiss team's work, which included 38 trials with a follow-up time of up to four years plus additional data on outcomes from 29 trials provided by manufacturers, was funded by the Swiss National Science Foundation.
REUTERS NC ND0855