The US Food and Drug Administration’s advisory panel yesterday gave a nod of approval to Abbott’s Xience stent, marking a major step towards full marketing clearance in coronary artery disease. However, it comes attached with provisos around a five-year post-approval study looking specifically at patient compliance with adjunctive antiplatelet therapy and major bleeding complications.

The Xience stent system is coated with the immunosuppressant compound everolimus, which directly inhibits smooth muscle cell proliferation associated with restenosis – the re-narrowing of arteries following balloon angioplasty – and is designed to dissolve inside the body after about three years.

The body of data submitted to the FDA included a 1,000-patient head to head study in which Xience demonstrated superiority to Boston Scientific’s already established Taxus in preventing the re-narrowing of arteries and in avoiding major cardiovascular adverse events (4.6% Xience versus 8.1% Taxus). But it’s not all bad news for Boston Scientific as Abbott supplies a private-label version of Xience, called Promus, to the firm as part of a distribution agreement established between the two companies last year when the latter acquired Guidant Corporation.

In October, the same panel gave the thumbs up to Medtronic’s Endeavour (zotarolimus) stent, so the battle is now on to become the first new competitor to Taxus and Johnson & Johnson’s Cypher stent in the multi-billion US market since 2004. Abbott is hoping to be able to launch Xience in the first quarter of next year, while Medtronic says it too plans a market introduction in the next few months pending full approval.

Their introduction should help buoy the stent market, which stumbled last year after it emerged that they may be linked to an increased risk of death and cardiac events compared with their bare metal counterparts. Both Abbott and Medtronic have emphasised the safety of their second-generation offerings in their submissions to the drug regulator.