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us antiobesity drug approval guideIinfs slimmed

Weight loss alone is an appropriate endpoint for the assessment of antiobesity agents in clinical trials and is sufficient for approval, the US FDA's Endocrino­logic & Metabolic Drugs Advisory Committee bas voted [Pink Shut: 3, 23 Jan 1995]. This decision goes somewhat in the face of the draft guidelines prepared by the FDA's Division of Metabolism & Endocrine Drug Products.· However. the drug product division has said that it has 'every intention ' of accepting the committee's advice on the guidelines.

The draft guidelines suggested that weight loss is only a surrogate marker for tbe efficacy of antiobesity agents, and that primary endpoints should include the prevention of comorbidities. However, the advisory committee felt that because of the timeframe required to see a reduction in comorbidities, they would be impractical to evaluate. The committee would, however, like to see a reduction in risk factors (such as elevated levels of lipids, insulin or glucose. or hypertension) as secondary endpoints.

Another issue was the length of time over which weight loss must be shown to be maintained. The draft guidelines suggested that 2 years would be appropriate. However, in recognition of the difficulty in retaining patients in double-blind. placebo­controlled trials for this length of time. the majority of committee members voted that a 5% weight loss maintained for I year would be sufficient for approval. Safety of the agents must be assessed over a 2-year period. nevertheless .

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