ARENA BEGINS PHASE IIB TRIAL OF ANTI-OBESITY COMPOUND

Arena Pharmaceuticals has started dosing patients in a Phase IIb clinical trial of APD356, an orally administered, internally discovered drug candidate for the treatment of obesity.

The trial will evaluate safety and weight loss in approximately 400 obese patients over 12 weeks. In a Phase IIa trial, APD356 demonstrated a highly statistically significant (p=.0002) average weight loss of 2.9 pounds in patients taking the 15 mg dose of APD356 versus 0.7 pounds for the placebo group, and was generally well-tolerated at all doses investigated.

The Phase IIb study is a randomized, double-blinded, dose-ranging study being conducted in the U.S. Approximately 400 obese patients will be randomized into four groups to evaluate the safety and efficacy of orally administered doses of 10 mg once daily, 15 mg once daily and 10 mg twice daily of APD356 compared to placebo for 12 weeks. The dose of 10 mg twice daily is expected to provide similar peak blood levels as the 15 mg once daily dose, but higher blood trough levels, thereby maintaining higher average drug concentrations in the blood.

The second dose will also provide a second peak in drug level to cover the evening hours. In addition to standard safety evaluations, patients will be assessed by echocardiogram prior to enrollment and at the end of the treatment period. Patients will not receive any diet or exercise advice, but will be required to abstain from consuming alcohol. With the exception of the length of the trial, the design of this trial is substantially similar to the design of the four-week Phase IIa study