SAN DIEGO, CA, USA I January 12, 2015 I Arena Pharmaceuticals, Inc. (NASDAQ: ARNA) announced today the initiation of patient dosing in a Phase 2 clinical trial of ralinepag, an oral, non-prostanoid prostacyclin (IP) receptor agonist intended for the treatment of pulmonary arterial hypertension (PAH).

“An intriguing component of this compound is the smooth peak-to-trough ratio, which may potentiate efficacy and minimize toxicity relative to currently available therapies,” said Lewis J. Rubin, M.D., Emeritus Professor of Medicine at University of California, San Diego, School of Medicine. “This clinical trial should help to further elucidate how ralinepag’s intrinsic properties translate to its efficacy and safety profile.”

This 22-week, randomized, double-blind and placebo-controlled Phase 2 trial will evaluate the hemodynamic and exercise capacity effects, safety and tolerability of ralinepag in up to 60 patients with PAH. During the first nine weeks of the trial, patients will be titrated to their individual tolerance level, and then sustained at this level for the remainder of the trial.

“We believe ralinepag offers promise in the IP receptor class of molecules given its oral availability, long plasma half-life, and high selectivity and potency in vitro,” said Jack Lief, Arena’s President and Chief Executive Officer. “In conjunction with our other clinical-stage programs, this compound further enhances our optimism about Arena’s value drivers.”

About Pulmonary Arterial Hypertension

PAH is a progressive, life-threatening disorder characterized by increased pressure in the arteries that carry blood from the heart to the lungs. The increased pressure strains the heart, which can limit physical activity, result in heart failure and reduce life expectancy. Based on data from the Registry to EValuate Early And Long-term PAH disease management (REVEAL) of patients in the United States, there is an estimated five-year survival rate of 57% from diagnosis.

About Ralinepag

Ralinepag, an orally available agonist of the IP receptor, is an investigational drug candidate internally discovered and developed by Arena and intended for the treatment of vascular diseases, including PAH. In Phase 1 trials, ralinepag showed an approximate 25-hour half-life, indicating that the compound could be dosed once or twice daily. Arena believes that an orally available, non-prostanoid IP receptor agonist that provides clinical benefits similar to currently available IP receptor agonists has the potential to improve treatment for patients with PAH. The FDA has granted ralinepag orphan drug status for the treatment of PAH.

About Arena Pharmaceuticals

Arena is embracing the challenge of improving health by seeking to bring innovative medicines targeting G protein-coupled receptors to patients. Arena’s internally discovered drug, BELVIQ® (lorcaserin HCl), is approved in the United States, and Arena is focused on discovering, developing and commercializing additional drugs to address unmet medical needs. Arena’s US operations are located in San Diego, California, and its operations outside of the United States, including its commercial manufacturing facility, are located in Zofingen, Switzerland. For more information, visit Arena’s website at www.arenapharm.com.

SOURCE: Arena Pharmaceuticals