I take heart in the pre-clinical results that showed excellent responses in mice with tissue as close to human as possible. They were not borderline improvement, they looked like complete cure. I believe the 200 was just the start of the activation zone for Prurisol in the psoriasis indication and that the 300 and 400 doses (not sure which one) will result in the maximum response in the activation zone.
Could things not go great, yes, but I think our chances for excellent results are way above negative to no improvement results.
FYI, not sure what a U shape dose vs PASI 75 is. Glad to hear you appear positive in regards to upcoming P results.