Researchers Study Multi-Purpose Drug
February 01, 2006
Narrowed Arteries: A Major Cause of Heart Attack and Stroke
Researchers at the University of Rochester Medical Center today announced that they have launched a study to determine whether an experimental drug, rimonabant, can slow atherosclerosis, the fatty build-up in arteries that creates heart attack risk. In recent studies, rimonabant has been shown to decrease body weight, improve abnormal levels of blood sugars and fats (cholesterol) and to help willing patients quit smoking. Now researchers hope to add coronary artery disease (CAD), atherosclerosis within the arteries of the heart, to the list of maladies addressed. A decision on whether rimonabant is safe and effective and if so, for which uses, is expected from the U.S. Food and Drug Administration in 2006.
Unlike previous cholesterol drugs that treat some aspect of blood or blood vessel walls, rimonabant is a cannabinoid receptor antagonist, which exerts its effect in parts of the brain that control appetite and addictive behaviors. Results of previous studies show that rimonabant reduces triglycerides and increases HDL-C, or “good” cholesterol, independent of weight loss. The new study, titled STRADIVARIUS (Strategy to Reduce Atherosclerosis Development Involving Administration of Rimonabant- The Intravascular Ultrasound Study), will explore whether these effects will impact the progression of atherosclerosis.
“Obesity, diabetes, high cholesterol and coronary artery disease have all reached epidemic proportions to become leading causes of death despite being largely preventable,” said Frederick S. Ling, M.D., director of the Cardiac Catheterization Laboratory, associate professor of Medicine at the medical center and principal investigator for STRADIVARIUS. “These risk factors, called metabolic syndrome when combined in one person, feed off each other and are made much worse by smoking. New approaches are urgently needed, and our lab has the tools to measure accurately whether new treatments actually slow the progression of coronary artery disease.”
Specifically, people with metabolic syndrome have at least three of the following risk factors: abdominal obesity, high blood pressure, insulin resistance/high blood sugar (precursor to diabetes), and blood lipid disorders (high triglycerides or low good cholesterol (HDL-C)). The 50 million Americans with the syndrome are at increased risk for CAD, which takes 500,000 lives per year, according to the American Heart Association. By further worsening disease in coronary arteries, smoking puts 47 million Americans at even greater risk.
STRADIVARIUS is a randomized, placebo-controlled, phase III research study that has almost completed enrollment. The study goal is to enroll 800 patients worldwide, including 500 from the United States and 10 in Rochester. Patients are randomized to receive either placebo or a 20 mg tablet of rimonabant (proposed trade name: Acomplia) daily for an 18-month period.
The progress of coronary artery disease will be measured by using intravascular ultrasound (IVUS) when patients are referred initially for a coronary angiogram. At their 18-month visit, a repeat IVUS will be performed. IVUS is a newer imaging technique that uses computer analysis of ultrasound energy to capture images of the insides of blood vessels. Researchers believe it has the potential to more accurately measure the degree of narrowing (stenosis) and plaque build-up (fatty deposits) within an artery than x-ray-based techniques.
To qualify for the study, patients must be referred by their physicians to undergo a coronary angiogram. Patients qualify if there is a 20 percent, but less than 50 percent, stenosis in one of their coronary arteries (mild CAD). Stenosis is an abnormal narrowing in a blood vessel, an effect of damaging deposits (cholesterol, calcium) within arterial walls.
If the narrowing leads to blockage by a blood clot of a coronary artery, heart attack occurs. Only patients with mild CAD will be included in STRADIVARIUS because those with an artery more than 50 percent closed may need treatment for the blockage, such as angioplasty (balloon or stent) or heart bypass surgery.
While enrollment in the study is closed locally, those interested can find more information about STRADIVARIUS and the catheterization lab by visiting their website below.