FDA approval on the current review cycle?
I'd guess somewhat less than 50%. Even without a REMS they would certainly want a post-marketing study, and they still have to decide on the risk/benefit equation.
With Qnexa there is an objective issue (birth defects) that provokes the REMS. But here what is that issue? Something to make sure it is not prescribed to rodents? Would have to be something like the FDA saying we are only approving this for people with BMI>x, and because of the limited knowledge about cardiac effects we want to makes sure that scripts are limited to that population. But that's kind of a weird REMS program.