Arena Pharmaceuticals, Inc., a biopharmaceutical company, focuses on providing novel medicines with pharmacology and pharmacokinetics to patients worldwide.

The company's investigational clinical programs include Etrasimod (APD334) that is in Phase III clinical trial for ulcerative colitis, Phase IIb/III clinical trial for Crohn's disease, Phase II clinical trial for alopecia areata, Phase III clinical trial for atopic dermatitis, and Phase IIb clinical trial for eosinophilic esophagitis; Olorinab (APD371), which is in Phase IIb clinical trial for the treatment of abdominal pain associated with irritable bowel syndrome; APD418 that is in Phase II clinical trial for acute heart failure; and Temanogrel for coronary microvascular obstruction that is in Phase II clinical trial.

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; Eisai Co., Ltd. and Eisai Inc.; Boehringer Ingelheim International GmbH; Beacon Discovery, Inc.; and Aristea Therapeutics, Inc.

Arena Pharmaceuticals, Inc. was incorporated in 1997 and is based in Park City, Utah.

As of March 11, 2022, Arena Pharmaceuticals, Inc. operates as a subsidiary of Pfizer Inc.