Orexigen's Empatic Phase 2b results demonstrate weight loss

Orexigen® Therapeutics, Inc. (Nasdaq: OREX) today announced that its 24-week, Phase 2b trial for Empatic(TM) (bupropion SR/zonisamide SR), the Company's second late stage investigational combination drug for the treatment of obesity, met its primary efficacy endpoint by demonstrating statistically significantly greater weight loss for both Empatic doses compared to monotherapies and placebo. The Company plans to meet with the U.S. Food and Drug Administration (FDA) for an End of Phase 2 meeting to discuss these data with the goal of defining a Phase 3 plan for Empatic.

"We believe that the Empatic Phase 2b results demonstrate early and meaningful weight loss that exceeds both the mean and categorical efficacy benchmarks set by the FDA for one year Phase 3 trials. Furthermore, the trajectory of weight loss at 24 weeks suggests that there may be additional therapeutic benefits in longer trials," said Mike Narachi, President and CEO of Orexigen. "These positive results affirm the strength of our obesity franchise and the potential to offer different mechanisms to treat this complex disease and meet the diverse needs of patients."

Key top-line data from this study include the following:

• Patients completing 24 weeks of Empatic360 (bupropion SR 360 mg/zonisamide SR 360 mg) therapy lost 9.9% of their baseline body weight, or 22 pounds, compared to 1.7% for placebo patients (p<0.001).
• Of patients who completed 24 weeks of therapy on Empatic360, 82.6% lost at least 5% of their baseline body weight and 47.7% lost at least 10% of their baseline body weight compared to 18.9% and 5.7% of placebo patients, respectively (p<0.001 for both).
• Empatic patients experienced significant weight loss as early as their first post-baseline visit at week four. Importantly, Empatic patients continued to lose weight through the end of the trial period, with no evidence of a weight loss plateau.
• Improvements were observed in key markers of cardiometabolic risk such as waist circumference, triglycerides, fasting insulin and blood pressure.
• The most commonly reported adverse events for all Empatic patients were headache, insomnia and nausea. The most common adverse events leading to discontinuation were insomnia, headache and urticaria (hives).
• Adverse events and laboratory findings appeared to be consistent with the individual components of Empatic. There were no serious adverse events attributed by investigators to study drug. There were no statistically or clinically meaningful differences between Empatic and placebo on measures of cognitive function, depression, suicidality or anxiety.

"Obesity is a complex disease that is challenging to treat. What works for one patient may not work for another, making it critical to have a broad spectrum of interventions available for physicians and their patients," said Caroline Apovian, M.D., Director of the Center for Nutrition and Weight Management, Boston Medical Center. "These Phase 2 data show impressive weight loss among patients treated with Empatic and support further investigation to determine the full potential of Empatic."

These data follow the announcement by the Company in July 2009 that Phase 3 trials evaluating Contrave® (bupropion SR/naltrexone SR), its lead investigational drug for the treatment of obesity, met their co-primary endpoints, exceeding the FDA categorical efficacy benchmark for clinically significant weight loss. The Company remains on track to file a New Drug Application (NDA) for Contrave with the FDA in the first half of 2010.