Arena Pharmaceuticals, Inc. is an American biopharmaceutical company founded in 1997 and headquartered in San Diego, California.

[3] The company has small molecule drugs in development for possible clinical utility in multiple therapeutic areas.

The company's most advanced investigational clinical programs are ralinepag (formerly APD811) in testing for pulmonary arterial hypertension (PAH), etrasimod (formerly APD334) in evaluation for inflammatory indications and APD371 for the treatment of pain associated with Crohn's disease.

[9] Arena Pharmaceuticals Inc. is an American biopharmaceutical company founded in 1997 and headquartered in San Diego, California.

Drugs in the company's pipeline includes medications designed to treat pain, ulcerative colitis and pulmonary arterial hypertension.