Drug Lowers Conversion to Type 2 Diabetes by 81% in Multicenter Study

June 2008 - In a research study of hundreds of patients facing the prospect of developing type 2 diabetes, the oral drug pioglitazone (brand name: Actos) reduced the rate of conversion to the disease by 81 percent in the active therapy group compared to those taking a placebo, the study leader, Ralph A. DeFronzo, M.D., reported June 9 during the 68th Scientific Sessions of the American Diabetes Association in San Francisco.

Individuals randomized to take pioglitazone also recovered part of their insulin production and their bodies became more sensitive to insulin, therefore using it more efficiently to control plasma glucose or blood sugar, Dr. DeFronzo, professor and chief of diabetes at The University of Texas Health Science Center at San Antonio, said.

He designed and led the four-year ACTos NOW for the Prevention of Diabetes (ACT NOW) Study that enrolled 602 individuals with impaired glucose tolerance, a prediabetic state, along with 102 healthy controls.

Currently no drug is approved by the U.S. Food and Drug Administration for treatment of prediabetes to prevent progression to diabetes.

The maker of Actos, Takeda Pharmaceuticals of Japan, funded the study but gave the researchers complete freedom to perform the study and interpret the results, whether positive or negative, Dr. DeFronzo said.

The study was conducted at eight of the foremost centers for diabetes in the U.S. The American Diabetes Association labeled the ACT NOW presentation late breaking and clinically relevant.

Pioglitazone corrects two core defects in type 2 diabetes, insulin resistance and beta cell failure. Beta cells are the cells in the pancreas that secrete insulin.

"The drug is the best insulin sensitizer we have and it also preserves beta cell function," Dr. DeFronzo said. "The clinical response in this study is next to astronomical, not 100 percent but obviously highly significant."

Pioglitazone came to the U.S. market in 2000 and the original mechanism-of-action studies were conducted by the Division of Diabetes in the UT Health Science Center's School of Medicine.

Subjects in the ACT NOW study were treated at the clinical research area of the Texas Diabetes Institute, a comprehensive diabetes treatment and research facility staffed by UT Health Science Center faculty physicians in a University Health System facility on San Antonio's West Side.

About 1 in 10 individuals with impaired glucose tolerance shows signs of diabetic retinopathy (damage to blood vessels in the retina that may affect vision), and 5 percent to 10 percent of prediabetic individuals are estimated to have peripheral neuropathy (blood vessel damage in extremities). A drug to treat impaired glucose tolerance and prevent further decline is therefore of great importance.

"Prediabetes, I believe, is really diabetes," Dr. DeFronzo said.

In the ACT NOW study, 10 subjects with impaired glucose tolerance developed diabetes while taking pioglitazone. That compared to 45 subjects with impaired glucose tolerance who developed diabetes after receiving a placebo. Patients were randomly assigned to receive either active drug or a placebo.

Forty-two percent of individuals in the pioglitazone arm of the study returned to normal glucose tolerance at the study's end versus 28 percent of those in the placebo arm.

Pioglitazone was safe and well tolerated during the study. Weight gain and edema were more frequent in the treatment group.

Source: University of Texas Health Science Center at San Antonio