While Arena did announce a collaboration agreement in South Korea, the real news yesterday was a sales checkup from rival VIVUS ( NAS: VVUS ), whose obesity drug Qsymia hit the market in mid-September. Its weaker-than-expected results, along with discouraging commentary around insurance coverage, sunk all ships in the obesity space. While I didn't find anything too notable to merit a huge reaction in Arena shares today, the hangover from VIVUS' disappointing report could continue in today's session.