Medical device reviewers said a Cook Medical stent coated with a common cancer-fighting drug was safe and effective for treating clogged arteries in the thighs.

Zilver PTX, the first drug-coated stent to treat peripheral arteries, kept the blood vessels free from plaque longer than bare-metal stents, the Food and Drug Administration reviewers said in documents released on Tuesday.

Privately held Cook Medical competes against Boston Scientific and Medtronic, which also make leg stents, in a stent market estimated at $5 billion worldwide.

Stents are tiny mesh-like tubes used to prop open arteries that have been cleared of blockages.
The most commonly used drug coated stents are placed in heart arteries following angioplasty procedures.

The Cook Medical stent is coated with paclitaxel, an anti-cancer drug. The drug is used to help prevent reclogging of the artery by inhibiting the growth of scar tissue.

The FDA reviewers said Zilver PTX was better than the control arm in a clinical trial, but the small trial size of only 479 patients meant some safety risks could be hard to detect.

A panel of outside experts is scheduled to consider the Cook Medical device at a meeting on Thursday. The FDA will later make the final decision on whether to approve the stent for sale in the United States.

The device was approved for sale in Europe in 2009.

The Zilver PTX is meant to treat peripheral arterial disease, which affects about 30 million people annually, Cook said.

The disease develops when arteries outside the heart build up cholesterol and scar tissue, causing them to narrow and restrict blood flow.

The most common symptom of the disease is leg pain when walking, but only 33 percent of individuals with clogged peripheral arteries have symptoms, Cook said, meaning patients do not always know they have the disease.

Zilver PTX, made of a super-elastic alloy of nickel and titanium, is meant for use in clogged arteries above the knee, which supply blood to the knee joint and muscles in the thigh and calf.

Cook said its Zilver self-expanding stent, which has no drug coating, is already approved by the FDA for treating lesions in arteries in the pelvis.

Johnson & Johnson's Cypher stent, which slowly releases the anti-rejection drug sirolimus, was the first drug-coated stent on the U.S. market. It was approved by the FDA in 2003. In June, J&J said it would no longer sell its drug-coated heart stents, which have lost market share to rivals from Abbott Laboratories and Boston Scientific.