Evaluation of drugs for treating obesity.

Criteria for the evaluation of new drugs to treat obesity are important as guides for designing clinical trials to test these agents. These criteria must be developed in relation to the realities of obesity, which is a chronic disease associated with morbidity and mortality that is increased by visceral fat deposits. The observation that patients regain weight after stopping drug treatment for obesity argues for the proposition that drugs work only when taken and NOT that the drugs are ineffective. The analogy between the development of treatments for obesity to those for the treatment of hypertension is used to highlight potential areas for new developments. Several features of an ideal drug for the treatment of obesity are suggested. Criteria for evaluating new drugs include both primary and secondary endpoints. The primary endpoint for an anti-obesity drug should be weight loss, possibly by category of success. Losses of total body fat or visceral fat might be alternative primary endpoints. Secondary endpoints include reduction in risk factors for associated diseases and improvement in the quality of life. In trials where vigorous placebo designs including highly aggressive behavior modification or very-low-calorie diets were used, it may be difficult or impossible to detect a response to a drug.