Subjects

Male and female subjects aged between 18 and 65 with a diagnosis of moderate to severe psoriasis vulgaris (affected body surface area (BSA) ≥10%, Psoriasis Area Severity Index (PASI) score ≥12) for at least 6 months and a body mass index (BMI) ≤32 kg m⁻² were eligible for enrolment. Major exclusion criteria included a history of clinically significant diseases or abnormalities (including hepatitis B, hepatitis C, and HIV), an INR of >1.2, use of a systemic immunosuppressive agent or other systemic agents to treat psoriasis (prednisone, PUVA, phototherapy) within 4 weeks of treatment, receipt of topical treatment for psoriasis within 2 weeks of treatment, receipt of a live vaccine (s) within 1 month of treatment, or any contraindication to receiving the drugs included in the probe cocktail. During the trial, subjects were to refrain from use of drugs known to be CYP inhibitors or inducers or from systemic or topical psoriasis therapy.