Efficacy and Safety of LEO 19123 Cream in the Treatment of Psoriasis Vulgaris

Inclusion Criteria: * Signed and dated informed consent to be obtained prior to any trial related procedure, including washout. * Clinical diagnosis of psoriasis vulgaris involving trunk and/or arms and/or legs with a symmetrical distribution amenable to treatment with a maximum of 50 g/week of topical medication on each side of the body. At Visit 1, there should not be a difference between the right and left side of more than 1 for each of the PASI criteria (redness, thickness and scaliness). * A minimum PASI score for extent of 2 on each side in at least one body region (i.e. psoriasis affecting at least 10% of left and right arm, and/or 10% of left and right side of the trunk, and/or 10% of left and right leg). * Disease severity graded mild, moderate, severe or very severe according to the Investigator's global assessment (IGA) of disease severity on each side of the body. The assessment should be the same for both sides of the body. * Age 18 years or above * Male subjects, or females of non-childbearing potential (i.e. surgically sterile or at least two years postmenopausal) * Attending a hospital outpatient clinic or the private practice of a dermatologist Exclusion Criteria: * Subjects using systemic treatments with biological therapies with a possible effect on psoriasis vulgaris within 12 weeks prior to randomisation (e.g. alefacept, efalizumab, etanercept, infliximab, adalimumab) * Systemic treatment with all other therapies, besides biologics, with a possible effect on psoriasis vulgaris (e.g., corticosteroids, retinoids, immunosuppressants) within 4 weeks prior to randomisation (inhaled or intranasal steroids for asthma or rhinitis may be used) * PUVA or Grenz ray therapy within 4 weeks prior to randomisation * UVB therapy within 2 weeks prior to randomisation * Any topical treatment (except for emollients) of the trunk/limbs (except on flexures) within 2 weeks prior to randomisation * Topical treatment for other relevant skin disorders on the face and flexures (e.g., facial and flexural psoriasis, eczema) with potent or very potent (WHO group III-IV) corticosteroids, vitamin D analogues or retinoids within 2 weeks prior to randomisation * Topical treatment for other relevant skin disorders on the scalp (e.g. scalp psoriasis) with very potent (WHO group IV) corticosteroids, vitamin D analogues or retinoids within 2 weeks prior to randomisation * Planned initiation of, or changes to concomitant medication that could affect psoriasis vulgaris (e.g., beta blockers, ACE inhibitors, anti-malaria drugs, lithium) within 2 weeks prior to randomisation * Subjects who have received treatment with any non-marketed drug substance (i.e., an agent which has not yet been made available for clinical use following registration) within the 4-week period prior to randomisation * Subjects with current participation in any other interventional clinical trial * Subjects with any of the following conditions present on the treatment area: eczematous skin, atopic dermatitis, clinical infection, ulcers and wounds * Subjects with a history of serious allergy, allergic skin rash or sensitivity to any component of the investigational products or formulations being tested * Subjects with positive hepatitis B, C or HIV * Known or suspected severe renal insufficiency or severe hepatic disorders * Known or suspected disorders of calcium metabolism associated with hypercalcaemia * Current diagnosis of erythrodermic, exfoliative, guttate or pustular psoriasis * Planned exposure to the sun during the study that may affect psoriasis vulgaris (i.e., normal lifestyle outdoor activities are permitted but deliberate exposure to sunlight or artificial ultraviolet light should be avoided)