Arena Pharmaceuticals is a biopharmaceutical company founded in 1997 and located in San Diego, California. The company has one product on the market and several others in development. Lorcaserin is used long term for weight loss in those who are obese. It works by increasing feelings of fullness so that less food is eaten. The U.S. Food and Drug Administration (FDA) approved Lorcaserin on June 27, 2012. Arena Pharmaceuticals is headquartered in Zofingen, Switzerland.