Arena Pharmaceuticals Initiates Phase 2b Clinical Trial of APD125 for the Treatment o...( SAN DIEGO April 8 2008 /- ArenaPh...),Health

SAN DIEGO, April 8, 2008 /PRNewswire-FirstCall/ -- Arena Pharmaceuticals, Inc. (Nasdaq: ARNA) announced today that it initiated screening in a Phase 2b clinical trial of APD125 in patients with primary insomnia. APD125 is an oral drug candidate discovered by Arena with the potential to reduce insomnia symptoms and improve sleep maintenance and quality.

The Phase 2b trial of APD125 is a double-blind, randomized, placebo- controlled subjective study evaluating the efficacy and tolerability of APD125 in patients with primary insomnia characterized by difficulty maintaining sleep. The trial, which is expected to enroll a total of approximately 675 male and female patients in about 70 clinical sites in the United States, will evaluate two doses (20 mg and 40 mg) and placebo over 14 nights of treatment. The trial will evaluate standard subjective measurements of sleep, including change from baseline in subjective number of awakenings after sleep onset (sNAASO), which is the primary endpoint.

"We are very encouraged by the emerging profile of APD125. We believe APD125 has the potential to significantly improve sleep maintenance and quality for patients with insomnia without the potential for dependence or impairing psychomotor function," said Jack Lief, Arena's President and Chief Executive Officer. "Results from this trial are expected around year end, and we believe they will increase our understanding of APD125 while supporting ongoing partnership efforts."

In a Phase 2a trial, when compared to placebo, patients treated with APD125 achieved statistically significant improvements in objective measurements of sleep maintenance, or the ability to maintain sleep during the night after falling asleep, and sleep architecture. T
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