Arena Pharmaceuticals (ARNA) shares rally ahead of PDUFA

Shares of Arena Pharmaceuticals are up huge in the last week ahead of today's PDUFA date for the company's obesity drug Lorcaserin. Piper attributes a lot of the share volume to retail investors, and points out Arena is a heavily shorted name. Piper believes Lorcaserin is well positioned to penetrate the large global obesity market and sees further stock upside should the FDA approve the drug.