Increasing competition is the name of the game in drug development - a boon to patients, but an added layer of complexity for investors. The obesity field is a case in point. Until a few months ago, no new products had shown up in the armamentarium in years. But it's now likely that there will shortly be three: Interneuron Pharmaceuticals Inc.'s Redux dexfenfluramine, Knoll Pharmaceutical Co.'s Meridia sibutramine hydrochloride monohydrate, and Roche Laboratories' Xenical orlistat.

To help keep the players straight, the following is a summary of market status, mechanism of action, clinical trial results, patient population and dosage for the three drugs.

Market status

Redux: Approved for marketing in April and launched in June. It is marketed by Wyeth-Ayerst Laboratories (Philadelphia, Penn.) and co-promoted by IPIC (Lexington, Mass.). Wyeth-Ayerst reported $38 million in sales to wholesalers for the quarter ended Sept. 30, which translates into about $48 million in retail sales. For the