Arena Pharmaceuticals Inc

American biopharmaceutical company in San Diego, California, founded in 1997 and listed on the Nasdaq until Pfizer bought it in 2022. Worked on small molecules acting on G protein coupled receptors, with the weight loss medicine lorcaserin in its earlier years and later a pipeline in immunology and inflammation led by etrasimod, a sphingosine-1-phosphate receptor modulator for ulcerative colitis and other conditions, together with cardiovascular and dermatology programmes.