This study will evaluate the pharmacokinetics and pharmacodynamics of BCT194 in psoriatic patients to better understand the skin penetration of topically applied BCT194.

Inclusion criteria:

• Male patients and post menopausal or surgically sterile female patients aged 18 - 75 years.
• Diagnosis of stable plaque psoriasis (with or without arthritis); diagnosed or history of psoriasis for at least 6 months prior to screening
• Psoriatic plaques accessible for microperfusion at body sites (e.g. trunk) convenient for the patients.

Exclusion criteria:

• Currently have any of the nonplaque forms of psoriasis: erythrodermic, guttate, or pustular.
• Currently have drug-induced psoriasis (new onset or exacerbation of psoriasis from beta blockers, calcium channel blockers, or lithium).
• Recent previous treatment with anti-TNF-α therapy (or other biological therapy), immunosuppressive agents such as cyclosporine, mycophenolate, pimecrolimus, or tacrolimus.
• Current signs or symptoms of severe, progressive, or uncontrolled renal, hepatic, hematological, gastrointestinal, endocrine, pulmonary, cardiac, neurologic, cerebral, psychiatric, or other disease which would make the patient unsuitable for the trial.
• Presence of major chronic inflammatory autoimmune diseases like rheumatoid arthritis, spondyloarthropathy, inflammatory bowel disease or systemic lupus erythematosus.
• Other protocol-defined inclusion/exclusion criteria may apply.