The University of Nebraska Medical Center is participating in an international clinical trial that provides a completely new approach for keeping stroke patients protected from another stroke or heart attack.
Called the IRIS (Insulin Resistance Intervention after Stroke) Trial, the study is unique because it targets insulin resistance, which affects nearly half of all patients who have had an ischemic stroke or transient ischemic attack (TIA).

“The IRIS Trial represents the first therapy specifically directed at treating the metabolic problem in stroke patients,” said Walter Kernan, M.D., professor of medicine at Yale University School of Medicine and the principal investigator on the study.

“We are using a drug which we believe can control insulin resistance and prevent stroke survivors from having a recurrent stroke or heart attack.”

The study is trying to determine the effectiveness of the drug, pioglitazone (trade name Actos™), in controlling insulin resistance. Pioglitazone is an FDA-approved drug used by millions of diabetes patients around the world.

UNMC is one of about 90 sites participating in the IRIS Trial. Pierre Fayad, M.D., the Reynolds Centennial Professor and chairman of the UNMC Department of Neurological Sciences, is the local principal investigator at UNMC, which is the only research site in Nebraska.

More than 1,700 patients have been enrolled in the study over the past four years. The goal is to enroll a total of 3,136 patients by the end of 2010. Patients from the United States, Canada and Israel are currently enrolling in the IRIS Trial, and there are plans to begin adding patients from Australia, England, Germany, Italy and China later this year.

Eligible participants in the trial would be men and women, age 39 years or older, who have experienced an ischemic stroke or TIA in the past six months. The patients must be non-diabetic, but have insulin resistance as determined by a special blood test. It is a randomized study with half the participants given pioglitazone and the other half given a placebo. Participants will be followed for an average of four years.

“We already have a number of drugs that can reduce the risk of strokes and heart attacks,” Dr. Fayad said. “These include aspirin and other agents used as blood thinners, statins to lower cholesterol, and blood pressure lowering medications to treat hypertension. If this drug (pioglitazone) works in controlling insulin resistance, it should give us another means of reducing recurrent strokes or heart attacks, adding to the treatments we already have.”

Insulin resistance is a common condition that affects about one of every four people. It is especially common in people who are older, inactive or overweight. Insulin resistance has recently been determined to cause atherosclerosis, the underlying disease that clogs vessels in strokes and heart attacks.

People who are insulin resistant are unable to efficiently metabolize sugar, the key energy source for the body. Pioglitazone allows these individuals to better metabolize sugar.