Treatment of high-risk patients with the oral antidiabetic drug Avandia reduces their risk of developing type 2 diabetes by nearly two thirds, researchers announced Friday.

Type 2 diabetes, the most common form of the disease, is closely linked to obesity and is on the rise around the world, fuelled by poor diet and sedentary lifestyles. Several drugs are used to treat type 2 diabetes, but none has so far been approved for prevention.

In a clinical trial of patients with poor glucose tolerance, 5,269 adults were assigned to receive Avandia or a placebo (sugar pill) daily for an average of 3 years.

At follow-up, the subjects in the Avandia group were 60 percent less likely to develop the disease or die than those in the placebo group, and their risk of progressing to full diabetes was reduced by 62 percent.

The Avandia patients were also 70-percent more likely to return to normal blood sugar levels. These patients did, however, have a small increased risk of non-fatal heart failure, a condition where the heart muscle is weakened and becomes unable to maintain adequate blood supply to the body’s tissues.

The overall findings suggest that adding Avandia plus adherence to basic lifestyle recommendations “substantially reduces the risk of developing diabetes,” the researchers conclude, “offering a novel preventive approach.”

All of the patients studied were told to exercise and eat sensibly during the 3-year trial, results of which were unveiled today at a European Association for the Study of Diabetes meeting in Copenhagen and also appear in this week’s Lancet medical journal.

The researchers, based at McMaster University, Hamilton, Ontario, Canada concluded that for every 1,000 people treated with Avandia for 3 years, about 144 cases of diabetes would be prevented and an extra 4 to 5 cases of heart failure would occur.

“The benefits substantially outweigh the harm,” said co-principal investigator Professor Salim Yusuf.

A total of 10.6 percent of those on Avandia progressed to diabetes in the study, compared with 25 percent given the placebo; in the active treatment group ,0.5 percent experienced heart failure compared with 0.1 percent on placebo. All heart failure cases were effectively treated.

The Canadian study also looked at the value of a blood pressure drug called ramipril, but found it did not reduce the risk of diabetes or death, although it did help some patients to return to normal blood sugar levels.

Ramipril is sold as Altace by King Pharmaceuticals Inc.

The study DREAM study (Diabetes REduction Assessment with ramipril and rosiglitazone Medication) was funded by the Canadian Institutes of Health Research, Sanofi-Aventis, GlaxoSmithKline and King Pharmaceuticals.

SOURCE: The Lancet, September 15, 2006.