Drug-Eluting Peripheral Stent Continues to Show Positive Data at Two Years

Patients treated with the Zilver® PTX™ Drug-Eluting Peripheral Stent maintained clinical improvement at two years, according to interim results from the Zilver® PTX™ Global Registry presented today as a late-breaking clinical trial at the Society for Cardiovascular Angiography and Interventions (SCAI) 33rd Annual Scientific Sessions. The prospective, single-arm study is ongoing to evaluate the drug-eluting stent for the treatment of peripheral artery disease (PAD). Results of a separate pivotal randomized study in a similar cohort of patients are expected to be available later this year.

In the meantime, this analysis includes 12-month follow-up data from 721 patients and 24-month follow-up data from 447 patients who received the Zilver® PTX™ paclitaxel-coated stent in the superficial femoropopliteal artery (SFA), a major artery above the knee. The registry study was designed to evaluate stent integrity, event-free survival and freedom from target lesion revascularization.

PAD affects more than eight million people in the U.S. and, if not treated, can limit the ability to walk and exercise, as well as place patients at risk for limb loss. PAD patients also have a greater chance of heart attack, stroke and death.

Although use of DES is common in the coronary arteries, the peripheral arteries, including those in the legs, experience different types of stress caused by walking and other movement. In some instances, blockages in these arteries are very difficult to treat, and may ultimately lead to limb amputation. The study is the third to evaluate the effectiveness of a drug-eluting stent outside of the coronary arteries, but the first to suggest clinical efficacy. The Zilver® PTX™ is an investigational device.

The characteristics of the 787 patients who were enrolled and treated included restenosis of previously treated lesions in 24 percent, in-stent restenosis in 14 percent, and total occlusions in 38 percent; 22 percent of patients had lesions longer than 15 cm. The mean lesion length was 10.0 +/- 8.2 cm, the mean percent diameter stenosis was 84.6 +/- 16.4 percent, with an average of 2.2 Zilver® PTX® stents used per patient.

At 12 months, the event-free survival rate was 87.0 percent, and freedom from target lesion revascularization was 90.5 percent. X-ray evaluation found a very low rate of stent fractures, 1.5 percent of patients at 12 months. Patients available for 24-month follow-up had an event-free survival rate of 80.0 percent, and freedom from target lesion revascularization was 83.3 percent.

This low rate of target lesion revascularization translated into meaningful clinical improvement for the majority of patients, with both the average walking distance and average walking speed more than doubling following Zilver PTX stent implantation, and being sustained to two years. In addition there was a very good safety profile, and a very low rate of stent fractures.

"These interim data suggest this device is safe and efficacious for the treatment of SFA lesions," said William A. Gray, M.D., FSCAI, who presented the study data and is associate professor of clinical medicine and director of endovascular services at Columbia University Medical Center/New York Presbyterian Hospital. "Prior attempts to demonstrate drug-eluting stent effectiveness using sirolimus or its analogues have fallen short, but the use of a paclitaxel-coated, non-polymeric stent appears to have improved the outcomes for patients who received this study stent. If these results are confirmed in the separate randomized study using the same device, it will be welcome news to patients who suffer from this disease."

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Stents no better than heart drugs in diabetics

Diabetics with stable heart disease do just as well taking drugs alone as getting quick angioplasty or bypass surgery to open blocked heart arteries, U.S. researchers said on Sunday.

They said patients advised to have angioplasty and a heart stent to restore blood flow and ease chest pain could safely wait and give drugs a chance to work.

But those with more severe disease sent for more invasive heart bypass surgery might be able to avoid a future heart attack if they have the surgery right away.

The study also found no difference in heart risks between two strategies for treating type 2 diabetes -- increasing the amount of insulin or lowering the body's resistance to its own insulin with drugs such as either metformin or GlaxoSmithKline's Avandia, also known as rosiglitazone, which had been thought to raise the risk of heart attacks.

"If you have diabetes and heart disease such that a bypass surgery is a recommended procedure, you should have that early rather than delaying it," said Dr. Trevor Orchard of the University of Pittsburgh, whose study appears in the New England Journal of Medicine.

Orchard said the study, also being presented at the American Diabetes Association meeting in New Orleans, offers evidence on how best to treat people with both type 2 diabetes and heart disease. More than 65 percent of people with diabetes die from heart disease or stroke.

For GlaxoSmithKline, the study represents a positive sign that Avandia may be safer than earlier analyses had suggested.

But it may be another blow for stent makers such as Boston Scientific Corp and Johnson & Johnson , whose U.S. sales plummeted after a similar study two years ago showed stents were no better than drugs at preventing death and heart attacks in all types of heart patients.

Stents are wire mesh tubes that prop open diseased arteries after they have been unclogged during angioplasty.

Questioning Angioplasty

In a commentary in the journal, Dr. William Boden of the University at Buffalo in New York said doctors should question why so many diabetics still get angioplasty.

"The continued high rate of use of (angioplasty) (1.24 million procedures per year in the U.S.) and the high rate of drug-eluting stent usage strongly suggests that we critically reassess our approach to revascularization, if needed, in diabetics with coronary disease," Boden wrote.

Diabetics with stable chest pain account for about 40 percent of all U.S. patients who get angioplasty, according to Wachovia analyst Larry Biegelsen, who said the findings could cut U.S. procedures by 3 percent.

The study involved 2,368 patients who either got treated right away with angioplasty, usually with a stent, and drugs or simply got drug treatment. It found no difference in the rates of death, heart attack or stroke after five years.

The study also looked at the risks and benefits of two strategies for controlling blood sugar in patients with type 2 diabetes, in which people lose the ability to use insulin.

One group took insulin injections or drugs known as sulfonylureas that boost the body's production of insulin. The other took insulin-sensitizing drugs like metformin or drugs known as glitazones, which include Avandia or Takeda Pharmaceutical Co's (4502.T) pioglitazone, brand name Actos.

Orchard said about 60 percent of patients in the insulin-sensitizing group took rosiglitazone or Avandia. He said there was no increased risk of heart attacks among patients in this group.

Source : www.reuters.com

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