Orexigen falls on Contrave briefing documents

Orexigen Therapeutics Inc. (NASDAQ:OREX) fell $0.66 (12%) to $4.81 on Friday after FDA questioned the safety and efficacy of Contrave in briefing documents posted ahead of Tuesday's Metabolic and Endocrine Drug Products Advisory Committee meeting to discuss the obesity candidate. Contrave has a Jan. 31 PDUFA date.

According to draft guidance for obesity candidates published by FDA in 2007, the placebo-adjusted weight loss must be 5% for those in the treatment arm of a study, or the proportion of patients who lose at least 5% of baseline body weight in the treatment group should be double the proportion in the placebo group. In the briefing materials, FDA said Contrave missed the first benchmark in all four Phase III trials included in the NDA, but met the second in three of the four trials. Pooled data from Orexigen's Phase III program show that low- and high-doses of the fixed-dose combination of naltrexone and bupropion produced placebo-adjusted mean weight loss of 3.7% and 4.2%, respectively. ...