Actually, I hypothesize that Belviq's advertising will only serve to help Qsymia in the end. If it's lack of awareness that's potentially hurting Vivus and Arena, should advertising bolster awareness of Arena, it will do so for the industry at large. When consumers spring to purchase Belviq and discover there is a more effective alternative available (Qnexa), that alternative will see increased popularity.
I don't see how ARNA fares significantly better than VVUS come launch. People just aren't running to their doctors to get these drugs. When it comes time for ARNA to launch their drug, its going to be the same story. a few thousand prescrtiptions rolling in each week. And then investors will be like, why is the market cap 1.5 billion, when they get 1/3 of a few tens of millions of revenue. And if fat americans aren't lining up to get these drugs, i doubt skinny Koreans are.