File photo / Bay of Plenty Times

File photo / Bay of Plenty Times

People taking the highest dose of a new anti-obesity drug lost more than a stone (6.4kg) in weight in 20 weeks, a study has shown.

The amount of weight lost was almost three times that in a control group given a placebo and 50 per cent more than those given a rival treatment, which is the current brand leader for the treatment of obesity.

The drug, liraglutide, is the first of a new class of anti-obesity agents which mimic the action of a hormone that occurs naturally in the gut, reducing hunger.

Experts said it had "great potential" because it also reduced the risk factors for Type 2 diabetes and heart disease.

Diabetes already affects more than two million people in Britain and is rising so fast it threatens to overwhelm the National Health Service (NHS).

But they warned that the high cost of the drug - around £500 (NZ$1097) for six months' supply at the lowest dose - could limit its use.

Liraglutide, made by Novo Nordisk, was licensed earlier this year as a treatment for diabetes and trials have so far shown it is safe.

In the first study in obese people without diabetes, published today in the Lancet, it has been shown to significantly reduce weight, with few side effects.

The study was conducted among 564 adults with a body mass index of over 30 and treated at 19 hospitals across Europe.

They were put on a diet containing 500 calories fewer than they needed each day, combined with an exercise programme and given liraglutide (in one of four different doses), or orlistat (brand name Xenical, the most popular anti-obesity treatment) or a placebo.

Those on the highest 3mg dose of liraglutide lost 7.2kg on average over 20 weeks, compared with 2.8kg on the placebo and 4.1kg with orlistat.

Liraglutide cut blood pressure and improved blood glucose control, reducing the risk of diabetes.

Professor Arne Astrup, head of the department of Human Nutrition at the University of Copenhagen, Denmark, who led the study, said: "The reason why we think this drug is so intriguing is that it mimics a gut hormone called GLP-1 which is released in the small intestine after eating.

"It tells the body to produce more insulin and the brain to stop eating. It is a naturally occurring satiety hormone.

"The problem is that it is eliminated from the blood stream within minutes. The company [Novo Nordisk] has added a molecule to make it more resistant to elimination, so it lasts for a full day."