Arena Pharmaceuticals, Inc., a clinical-stage biopharmaceutical company, focuses on the discovery, development, and commercialization of oral drugs for cardiovascular, central nervous system, inflammatory, and metabolic diseases. It is developing a pipeline of compounds targeting orphan G protein-coupled receptors using its drug discovery technologies, including constitutively activated receptor technology and Melanophore technology. The company?s drug candidate, lorcaserin hydrochloride, is in Phase 3 clinical trial program for the treatment of obesity. Its other lead development programs include APD125, a 5-HT2a serotonin receptor inverse agonist, which is in Phase 2 clinical trail for the treatment of insomnia; APD791, an anti-thrombotic drug candidate, which is in preclinical development stage for the treatment of arterial thromboembolic diseases, such as acute coronary syndrome. The company has collaboration agreements with Ortho-McNeil Pharmaceutical, Inc. for developing APD668, an orally administered drug candidate, which is under clinical development for the treatment of type 2 diabetes and other disorders; and with Merck & Co., Inc. for the development of MK-0354 for atherosclerosis and related disorders. Arena Pharmaceuticals was incorporated in 1997 and is based in San Diego, California.