As far as I understand, no patients with Psoriasis have been treated in the clinical trials to this point. They have been aimed at securing the 505b2 pathway.

"This study is designed as an open-label, randomized, 2-period, 2-treatment, 2-sequence, single-dose intensive pharmacokinetic (PK) study conducted in healthy volunteers.

https://clinicaltrials.gov/ct2/show/NCT02101216

Also, I believe the 2a was a crossover study rather than dose optimization study but if anyone knows I am missing something please do tell.