Drug hope for obesity

Obesity costs the NHS at least £0.5bn a year

An appetite drug which appears to significantly reduce fat consumption in rats could become the latest potential treatment for obesity.

But it remains to be seen whether the drug can work in humans.

Obesity is a growing modern epidemic in many developed countries - placing patients at far higher risk of heart disease, diabetes and other health problems.

The research, carried out at the drug firm Merck's laboratories in New Jersey in the US, has been published in the journal Nature Medicine.

In rats it has reduced fat intake by 20%, which, if reproduced in humans, would be very significant

Dr Julian Barth, Leeds General Hospital

Their compound, given to rats on a high fat diet, reduced body weight, and the laying down of fatty tissue compared to rats not given it.

When the same drug was given more directly into the rat's brains, it reduced food intake and body weight.

Insulin mimic

The drug works by acting on receptors in the brain which are normally sensitive to the hormone insulin as part of the mechanism which controls appetite.

Insulin cannot be given as a drug to trigger this mechanism because, if injected into the bloodstream, or taken in pill form, very little if any of the active hormone would ever make it to the brain.

The Merck scientists have developed a tiny protein which has a similar effect on the receptors as actual insulin.

However, this protein is not broken down in the gut, and can get into the brain.

This holds the promise of an "anti-appetite pill", if future tests suggest the "mimetic", or mimicking, molecule, can work in humans as well as rats.

One in five obese

"Our data demonstrate the unique advantage of small molecule insulin mimetics over insulin in controlling body weight," say the authors.

They say it offers a "novel" approach to tackling obesity and related metabolic disorders.

Dr Julian Barth, a consultant in metabolic medicine from Leeds General Hospital, said that the drug could potentially target appetite more directly than current medications.

"It's not a miracle cure," he said. "But in rats it has reduced fat intake by 20%, which, if reproduced in humans, would be very significant."

Statistics show most adults in England are overweight and one in five - around eight million - are obese.

A Commons Public Accounts Committee report suggests unless action is taken one in five men and 25% of woman could be obese by 2005.

Obesity costs the NHS at least £0.5bn a year in patient care and £2bn to the wider economy, for example in sickness absence.

In England alone obesity is responsible for 30,000 deaths annually.

And rates across the world have risen from 12% to 20% since 1991.

The research paper is outlined in the current edition of Nature Medicine magazine.