A Proof of Concept Study Comparing Three Doses of an Oral Solution of LEO 22811 With a Placebo Oral Solution for the Treatment of Psoriasis Vulgaris

Inclusion Criteria: * Following verbal and written information about the trial the subject must provide signed and dated informed consent before any study related activity is carried out, including activities relating to the washout period. * Clinical diagnosis of psoriasis vulgaris, for at least 6 months prior to randomisation, and currently covering at least 10% of the body surface area (BSA) * Candidates for systemic anti-psoriatic treatment * Psoriasis Area and Severity Index (PASI) ≥10 * Disease severity of moderate, severe or very severe according to the Investigators' Global Assessment of disease severity (IGA) * Aged 18 years or above * Any race or ethnicity * Males, surgically sterile females (bilateral tubal ligation, bilateral oophorectomy or hysterectomy) or post menopausal females (at least 1 year since last menses) * Attending hospital outpatient clinic or the private practice of a dermatologist Exclusion Criteria: * Systemic treatment with biological therapies whether marketed or not with a possible effect on psoriasis vulgaris within the following time periods prior to randomisation: * Etanercept - 4 weeks * Adalimumab, alefacept, infliximab - 2 months * Ustekinumab - 4 months * Systemic treatment with all other therapies (other than biologics) with a possible effect on psoriasis vulgaris (e.g.corticosteroids, retinoids, immunosuppressants, methotrexate, cyclosporin or fumaric acid) within 4 weeks prior to randomisation * PUVA therapy within 4 weeks …