An experimental obesity drug also appears to help reduce the health risks from Type 2 diabetes, researchers say.

The Sanofi-Aventis drug rimonabant, also called Acomplia, reduced risk factors for heart disease in people with Type 2 diabetes compared with those taking a placebo, European researchers report in Friday's online issue of the medical journal The Lancet.

Diabetes is a leading cause of heart disease, kidney failure, blindness and amputation. It kills more than 40,000 people a year in Canada.

In Type 2 diabetes, weight gain, poor nutrition and lack of exercise reduce the ability of insulin manufactured by the body to control levels of glucose (blood sugar) properly, producing a condition called insulin resistance.

Prof. Andre Scheen of the University of Liege in Belgium and his team studied 1,047 overweight and obese people with diabetes who did not respond to standard treatments.

The participants, who lived in 11 countries in Europe and North and South America, were randomly assigned to take either 5 g or 20 mg of the drug daily or a placebo for one year.

All participants were told to follow a diet that provided slightly fewer calories than they needed and were advised to exercise.

After a year, the weight loss results were:

• Those in the 5 mg group lost 2.3 kilograms.
• The 20 mg group lost 5.3 kilograms.
• Placebo group participants lost 1.4 kilograms.

Those who took the higher dose of the drug showed better blood glucose control, higher HDL or "good" cholesterol and improved triglyceride or blood fat levels, and reduced waist circumference — a sign of less abdominal fat.

"The improved blood sugar control plus weight loss achieved with rimonabant is very encouraging," Scheen said in a release. "Today, most medications for Type 2 diabetes are associated with weight gain and it is difficult for people with diabetes to lose weight and keep it off."

Side-effect questions

But it's premature to conclude that the drug helped diabetes risk beyond its weight-loss effects, two Scottish diabetes experts said in a commentary accompanying the study.

"The suggestion that [Acomplia] increases depression and anxiety is concerning," Stephen Cleland and Naveed Sattar wrote.

In each group, about one-third of the participants dropped out, which is common in weight-loss studies. Most did not drop out because of side-effects, but 11 people or three per cent of those in the high-dose group said depression led them to drop out, compared with three volunteers or 0.9 per cent in the placebo group and none in the lower-dose arm of the study.

Some people taking the drug also developed nausea, vomiting and anxiety.

Rimonabant is the first drug that works by blocking the cannabinoid-1 receptor, the same one marijuana targets in the brain. When the receptor is blocked in laboratory animals, they eat less and lose weight.

Regulators in Europe licensed the drug as a weight-loss pill in June, in combination with diet and exercise, for people who are obese and at risk for diabetes. In the U.S., the Food and Drug Administration has asked the company for more information about the drug. Rimonabant is not included in Health Canada's database of approved drugs.

Critics caution it's not known what other effects rimonabant may have on the metabolism, noting blockbuster drugs tested on thousands of people have shown unexpected side-effects when sold to millions of patients for years.

The research was sponsored by the drug's manufacturer.