That was my thinking too after a read of your original posting of those results, that the SCID model has flopped in ultimately predicting Psoriasis resolution in humans once before, so best we be somewhat dubious of its reliability in the Prurisol trial. Hope it pans out this time, but not perceiving it to be a slam dunk by any stretch.
As you're aware, model predictability in this industry is always challenging, I remember reading a top immunologist joking that he has cured (and killed) millions of mice in his lifetime. If only the jump to humans was seamless, we'd be a near immortal species.