This study will examine the safety and efficacy in subjects with moderate to severe psoriasis, as measured by Psoriasis Area and Severity Index(PASI), Body Surface Area (BSA), Dermatology Life Quality Index (DLQI) and other assessments.

Inclusion Criteria:

• Male or female subjects, ≥18 to ≤75 years of age, who have a diagnosis of chronic plaque psoriasis for at least 6 months prior to screening;
• Plaque psoriasis covering between 10% to 30 % of body surface area (BSA);
• PASI severity moderate to severe, scoring at least 10 but no higher than 20.

Exclusion Criteria:

• The subject presents with psoriasis that is predominantly guttate, erythrodermic, inverse, pustular or palmo-plantar or an unstable form of psoriasis;
• Previously failed (due to lack of efficacy) treatment with at least one systemic biologic agent for psoriasis (e.g. ustekinumab, adalimumab, etanercept, etc);
• The subject has not undergone wash-out periods of sufficient duration for the following treatments at Baseline: Topical psoriasis treatments: 2 weeks; Systemic (non-biologic) psoriasis treatments: 4 weeks or 5 half-lives (whichever is longer); Biologic psoriasis treatments: 8 weeks or 5 half lives (whichever is longer); Phototherapy: 4 weeks;
• The subject anticipates getting enough ultra-violet light during the study (e.g. sunbathing; tanning salon, etc.) to cause psoriasis to improve;
• History of cancer, with the exception of skin cancer.