Arena Pharmaceuticals, Inc., a biopharmaceutical company, focuses on providing novel medicines with pharmacology and pharmacokinetics to patients worldwide. Its investigational clinical programs include Etrasimod (APD334) that is in Phase III clinical trial for ulcerative colitis, a Phase IIb/III clinical trial for Crohn's disease, and a Phase IIb clinical trial for atopic dermatitis; Olorinab (APD371), which is in Phase IIb clinical trial for the treatment of abdominal pain associated with irritable bowel syndrome; and APD418 that is in Phase I clinical trial for acute heart failure. It also develops ralinepag (APD811), which is in Phase III clinical trial for pulmonary arterial hypertension. The company has collaboration agreements with United Therapeutics Corporation; Everest Medicines Limited; Beacon Discovery; Boehringer Ingelheim International GmbH; and Eisai Co., Ltd. and Eisai Inc. Arena Pharmaceuticals, Inc. was founded in 1997 and is based in San Diego, California.