Topical PH-10 Aqueous Hydrogel and Photodynamic Therapy for Psoriasis

This is an open label, single center, controlled study with each subject's two treatment plaque areas assigned by the investigator 1:1 to (a) PH-10 with ambient light exposure and (b) PH-10 with 544 nm LED light illumination at 10 J/cm2. A third plaque area will receive no treatment and serve as a control. Subjects with at least three distinct, stable study plaque areas will receive the experimental therapy to two treatment plaque areas twice a week (2-5 days apart) for the lesser of 12 weeks or until remission is observed in the treatment plaque areas. If remission is observed in a treatment plaque area then treatment of that area will be discontinued and the area assessed weekly. A third plaque area (control plaque area) will receive no drug or light treatment and serve as an internal control. Primary efficacy will be assessed 12 weeks after initial PH-10 treatment. Subjects will be followed for a total of 16 weeks to allow assessment of Durability of Response of treated lesions and comprehensive follow-up of adverse events.