Arena in my professional opinion will be the clear choice. Have followed all three companies for about 3 years now. As a physician, I would be prescribing Lorcaserin first and more often.
#1 much better safety profile
#2 single agent, easier to use
#3 mechanism of action is clearer, and it is a novel agent
I do admit both VVUS and ARNA will likely get the approval nod now that Congress is calling out the FDA to better address obesity. There is lots of room in the market.
I know for a fact, the whole conundrum of rat tumor scare at Arena's AdCom panel was created by falsely presented data, whether purposefully or not. Arena is 75% of way towards disproving this misrepresentation and data so far shows Lorcaserin even safer than the original data. Only major outstanding study is 3 month prolactin study, already underway and perhaps even completed.