Arena Pharmaceuticals, Inc., a biopharmaceutical company, announced that the United States Adopted Names (USAN) Council has approved the nonproprietary name etrasimod (pronounced Et-ras'-i-mod) for APD334, a selective oral, investigational, Sphingosine 1-Phosphate Subtype 1 (S1P1) receptor modulator with therapeutic potential in autoimmune diseases. Arena is currently studying etrasimod in a phase 2 clinical trial for ulcerative colitis.

"Given the limitations of currently available treatments for ulcerative colitis, including challenging effect profiles, we believe etrasimod has the potential to become the standard of care," said Amit Munshi, president and chief executive officer of Arena. "We look forward to the results of our phase 2 clinical trial of this promising compound."

Etrasimod is a potent and highly selective, orally available investigational drug candidate that targets the S1P1 receptor. S1P1 receptors have been demonstrated to be involved in the modulation of several biological responses, including lymphocyte trafficking from lymph nodes to the peripheral blood. By isolating subpopulations of lymphocytes in lymph nodes, fewer immune cells are available in the circulating blood to effect tissue damage.

Ulcerative colitis is a chronic disease that affects the large intestine. The innermost lining of the large intestine becomes inflamed and ulcers may form on the surface, which can cause symptoms such as frequent bowel movements, diarrhea and bloody stools. The inflammation is usually found in the rectum and can include all or a portion of the colon. Currently available treatment options have limitations in terms of side effects, patient response, efficacy and administration. Arena believes that an effective, orally available S1P1 receptor modulator that provides clinical benefits without current limitations has the potential to improve treatment for patients with ulcerative colitis.

The USAN Council, tri-sponsored by the American Medical Association, the United States Pharmacopeial Convention and the American Pharmacists Association, serves the health professions in the United States by selecting simple, informative and unique nonproprietary names for drugs by establishing logical nomenclature classifications based on pharmacological and/or chemical relationships. The USAN Council aims for global standardization and unification of drug nomenclature and related rules to ensure that drug information is communicated accurately and unambiguously, working closely with the World Health Organization's International Nonproprietary Name Programme and various national nomenclature groups.