Stenting is growing in popularity as a means of keeping arteries narrowed by atherosclerotic plaques from closing completely, precipitating a heart attack or other major cardiovascular event. The device functions as a scaffold, supporting the walls of the affected artery and preventing closure.
So-called 'bare' stents have been used for more than 20 years, but while effective they have limitations, notably that the artery tissue can in time grow through their mesh structure and reclose the vessel. The solution is to coat the stent with a drug that can prevent this tissue growth.
Occam's technology combines a drug delivery coating with a drug compound - Biolimus A9 - that prevents re-narrowing of treated arteries after coronary intervention. It will be used in Xtent's Custom NX Coronary Stent system, developed for treating diseased arteries that cannot be treated effectively by existing stents (e.g. blood vessels with long lesions and those that occur in small vessels).
Market research shows that these difficult cases represent over 40% of the procedure volume and account for more than 60% of the total expenditures for coronary stents.
Stenting has tended to be more popular in the US than in Europe, but this has changed with the launch of the first drug-coated products from Johnson & Johnson (Cypher) and Guidant (Achieve).
"Since the introduction of drug-eluting stents, our practice has evolved to significantly higher stent utilisation rates," said Prof Eberhard Grube, chief of cardiology at the Siegburg Heart Centre in Germany. "This reflects our desire to optimise the treatment of patients with more challenging coronary artery disease states, particularly cases of extensive disease and long lesions."
Market research has suggested that the market for drug-coated stents could be worth as much as $5 billion in 2005, a remarkable growth considering sales were non-existent until the end of 2001 in the US and 2002 in Europe.
The drug and temporary coating are currently being evaluated in a multicentre clinical study called Stealth I.
Under the terms of the agreement, Occam will license certain intellectual property rights to Xtent and provide stent coating services to Xtent, and in return will receive an up-front cash payment and royalties.