Abbott Laboratories said its new drug-eluting stent Xience V was more effective than Boston Scientific’s rival stent Taxus in a 300-patient study, although the shine was taken off the results by the furious debate over the safety of the entire drug-eluting stent class raging at the World Congress of Cardiology in Barcelona (see lead story).

The study, called SPIRIT II, showed that Xience V was superior to Taxus Express 2 in preventing in-stent late loss - a measure of the change in the vessel diameter between the time immediately following stent placement and at six months. Both stents release the drug paclitaxel, while Cypher is coated with another agent called sirolimus.

Secondary endpoints of the trial also demonstrated positive results for Xience V, including a statistically significant reduction in percent diameter stenosis from 21% for Taxus to 16% for Abbott’s device.

Armed with the data, Abbott said it would press ahead with a European launch of Xience V next month, providing competition to current market leaders Taxus and Cypher from Johnson & Johnson.

Between them, these two products dominate the $5.5 billion global coated stent market, with roughly a half-share a piece, although next-generation products such as Xience V and Medtronic’s Endeavour (zotarolimus) are expected to make significant inroads into the marketplace in the coming years.

Medtronic has launched Endeavour in Europe and other parts of the world and is scheduled to introduce it in the USA next year. Meanwhile, Canadian firm Conor MedSystems earlier this year won European approval to sell its own paclitaxel-eluting stent, CoStar, in competition to Taxus. Conor is suing Boston Scientific to try to invalidate the patent protection on Taxus' paclitaxel coating. Abbott hopes to launch Xience V in the USA in 2008.

In April, Abbott acquired Xience V as part of the vascular intervention and endovascular solutions businesses of Guidant.