Then by that rationale it is not a conservative tr

Then by that rationale it is not a conservative trial to go after mild/moderate cases but in fact a ambitious and difficult endpoint. Again the PR language reads:
"Clinical signs that psoriasis is clearing typically are more noticeable in patients with a greater severity of symptoms. This translated into a rigorous and aggressive study design for the Prurisol trial."

I stand corrected. This is an even better outcome for P as it meet the aggressive and difficult endpoints, while also showing it is potentially even more effective in the more severe cases. Seems like a extreme success to me.