Safety, Tolerability and Efficacy of SNA-120 for Treatment of Pruritus and Psoriasis in Subjects Treated With Calcipotriene

All subjects are required to meet eligibility requirements and undergo a calcipotriene run-in period (Part A) prior to qualifying and randomizing into the study to receive either SNA-120 or Placebo ointment in combination with calcipotriene ointment (Part B). Combination therapy (SNA-120 ointment + calcipotriene ointment or Placebo ointment + calcipotriene ointment) is to continue over an 8 week period to evaluate safety, tolerability and the efficacy of treatment on both persistent pruritus and the visible signs and symptoms of psoriasis.