New weight-loss drug backed in study (Reuters)

Reuters - An anti-obesity drug that turns off the same brain circuits which trigger the marijuana-induced munchies appears to produce sustained weight loss among patients who took it in a two-year study, researchers said on Tuesday.

The report by New York's Columbia University College of Physicians and Surgeons also said the drug -- Sanofi-Aventis SA's Acomplia, or rimonabant -- needs additional study for its long-term effects and said the research was limited by a high dropout rate. The drug company funded the study.

The drug is awaiting an approval decision by the U.S.

Food and Drug Administration. However there has been speculation that it could become the world's first blockbuster anti-obesity medicine, with analysts estimating sales topping $3 billion a year.

Tuesday's report, carried in the

Journal of the American Medical Association, was based on a study involving more than 3,000 patients that began in 2001 and also involved diet and exercise changes. The basic findings were released at an

American Heart Association meeting in late 2004.

The final study said the drug plus diet and exercise "promoted modest but sustained reductions in weight and waist circumference and favorable changes in cardiometabolic risk factors" such as cholesterol and triglycerides.

Up to 48 percent of the patients in the study saw a weight loss of 5 percent or more after one year, depending on the dose of the drug.

In addition, the report said, the favorable changes in cholesterol and triglycerides "appeared to be approximately twice that expected from weight loss alone," suggesting the drug may have some direct impact on fat metabolism beyond that caused by slimming down.

BLOCKS RECEPTORS

"It must be acknowledged that the trial was limited by a high dropout rate and that long-term effects of the drug require further study. Still, our observations collectively suggest that rimonabant may well represent an innovative approach to the management of multiple cardiometabolic risk factors, facilitating and maintaining improvements through weight-loss dependent and independent pathways," the study concluded.

Rimonabant is the first of a new class of drugs that works by blocking cannabinoid receptors found in the brain and other body tissues which stimulate eating in general and are the culprits in hunger after marijuana use.

In an editorial commenting on the report, experts from the U.S. National Heart, Lung, and Blood Institute sounded a cautionary note, saying that while the study showed promise the researchers should have done more follow-up work. They also said the study had found a higher rate of psychiatric disorders among those who received the drug compared to those who got an inert placebo.

Because obesity seems to be a societal problem, attacks against it "are needed in settings where people live, work, and play as well as in clinical practice. Drug treatments for obesity should be considered within this broader context and their current role should be limited pending further evidence," it said.