A Phase 2 Study of Cellular and Immunologic Changes in the Skin of Subjects Receiving PH-10

Inclusion criteria

• Men or women, age 18 or older.
• Presence of mild to moderate plaque psoriasis on the trunk or extremities (excluding palms, soles, scalp, and facial or intertriginous areas).
• At least one target plaque having a minimum diameter of 5 cm (2 inches) with uniform mild to moderate plaque psoriasis.
• Fitzpatrick skin type I-VI.
• Written informed consent by the subject or legal guardian.

Exclusion criteria

• Female subjects of childbearing potential who are pregnant, attempting to conceive, not using effective contraception, or who are nursing an infant.
• Subjects who have received PH-10.
• Subjects who have received PUVA or systemic antipsoriatic therapy (immunosuppressants, cytostatics, corticosteroids) within 28 days of study initiation (14 days for methotrexate).
• Subjects who have received UVB light therapy within 14 days of study initiation.
• Subjects who have received topical antipsoriatic therapy (including corticosteroids, tar, anthralin or Vitamin D analogs) to the study plaque areas within 14 days of study initiation.
• Subjects who have received any approved or investigational biologic drug therapy for psoriasis within 90 days or 5 half-lives of study initiation.
• Subjects who have participated in a clinical research study within 28 days of study initiation.
• Subjects with a history of porphyria, systemic lupus erythematosus or xeroderma pigmentosum.
• Subjects with clinical conditions that, in the opinion of the Investigator, may pose a health risk to the subject because of involvement in the study or detrimentally affect regular follow-up of the subject.