Obesity became a hot research area two years ago when Amgen Inc. paid $20 million to Rockefeller University for rights to the obesity (leptin) gene, the cloning and sequencing of which was described in the December 1994 issue of Nature.

Yet for all the work being done in the area - at least 35 companies are working on obesity (see table, A4) - the market remains wide open. Only a handful of products have been approved, most notably Interneuron Pharmaceuticals Inc.'s Redux dexfenfluramine, and all have only modest effects.