Arena Pharmaceuticals’ lead obesity compound enters phase II

APD356 is a selective agonist of 5-HT2C serotonin receptors, which are concentrated in the hypothalamus, an area of the brain known to play an important role in regulating food intake and metabolism.

This phase II clinical trial of APD356 is a randomized, double-blinded, multiple-dose, 28-day trial examining 400 obese volunteers. Arena expects that the trial will compare doses of 1mg, 5mg and 15mg of APD356 to a placebo and will evaluate weight loss after administration once daily for 28 days.

Doses for the phase II trial were chosen to bracket the 10mg dose that evidenced a pharmacologic signal (a reduction in meal size) with a single dose in Arena’s phase Ia trial. The 1mg dose was chosen as the lowest dose because Arena believes that a 1mg dose has the potential to produce therapeutic drug levels in the central nervous system if APD356, as observed in rats, achieves higher concentrations in the human brain than in blood.

“The initiation of this phase II trial of our lead anti-obesity compound marks a significant achievement for Arena,” stated Jack Lief, Arena’s president and CEO. “We anticipate that this phase II study will provide further favorable safety data and validate the preliminary efficacy data observed in earlier pre-clinical studies of APD356.”

Arena expects to announce initial results from this trial in the second quarter of 2005.