Obesity Drug Hype Takes Downturn

The antiobesity agent leptin, which showed impressive results in overweight mice and sparked numerous stories in the scientific and lay media, may not be effective in the people who need it most, ie the very obese.

Researchers in the USA have found that very fat people already tend to have high levels of leptin in their bodies. Two studies reported in Nature Medicine (September issue) found that the ob gene is far more active in the obese than in lean people, and the levels of leptin (the ob gene product) are around 20-30 times higher. It has been suggested that one of the reasons for obesity may be that the chronically overweight have a "leptin-resistance" phenotype, perhaps because of defective receptors.

However, Stephen Burley of the Howard Hughes Medical Institute at Rockefeller University, who worked on the recently-reported mouse studies (Marketletter July 31), said that pushing the doses of leptin higher may be sufficient to get a response in the very obese.