You know, upon thinking about it, I'm not sure that many (or even most) clinical trials use one-sided testing. It makes sense to do so, and would increase power for the particular side chosen, but I can't recall ever seeing it in a paper.
I've seen it in a couple of low-key (read: Non-FDA) trials, but for anything FDA-scale I think most people are wary about submitting studies that presume their subject can't possibly have -worse- results. If it's one of the early Phase 3's, it's just an unwarranted assumption, and people will be all over you for picking a more lenient study design without damn good reason to.
