Double-blind, Randomised, Placebo-controlled Trial Investigating BIRT 2584 XX in Patients With Moderate/Severe Psoriasis

Inclusion criteria

Inclusion\_Criteria: 1. Age 18 to 75, males or females 2. Patients with stable moderate to severe plaque-type psoriasis involving ?10% body surface area, with minimum disease severity PASI ?10 and with static PGA of at least moderate (score of at least 3) at screening visit 3. Psoriasis disease duration of at least 6 months prior to screening 4. Patients must be candidates for systemic psoriasis treatment or phototherapy 5. Patient must give informed consent and sign an approved consent form prior to any study procedures, including wash out of prohibited medications (Patients participating in the PK sub-study will sign an additional consent form. Refusal to participate in the sub-study will not exclude from participation in the main trial) Exclusion\_Criteria: 1. Patients with primary guttatae, erythrodermic, or pustular psoriasis 2. Patients who have previously discontinued efalizumab treatment due to lack of efficacy 3. Patients using treatments that could interfere with the primary endpoint of the study (cf. protocol section 4.2.2.1) 4. Patients on treatment with warfarin, paracetamol (acetaminophen), some NSAIDs, some antidepressants, medications known to induce or inhibit CYP3A4, or any other concomitant medication where potential drug-drug interactions with BIRT 2584 XX could either result in decreased efficacy or an unacceptable benefit-risk assessment, and where replacement of that concomitant medication with a safe equivalent drug is not possible (cf. protocol section 4.2.2.2 and the Investigator Site File). 5. Patients with active liver disease or history of any significant liver disease. 6. Any clinically significant illness or unstable disease which according to investigator judgement may either put the patient at risk because of participation in the study or may influence the results of the study or the patients ability to participate. 7. Patient with serum creatinine and/or white blood cell count \>1.5 x ULN at screening. (Repeat laboratory is allowed once between screening and randomisation prior to excluding the patient) 8. Patients with ALT, AST and/or total bilirubin \> 1.5xULN at screening (Repeat laboratory is allowed once between screening and randomisation prior to excluding the patient) 9. Abnormal values of other laboratory parameters at screening that would define a clinically significant disease as described in # 6 above (Repeat laboratory is allowed once between screening and randomisation prior to excluding the patient) 10. Positive testing at screening, or history of HIV or hepatitis B or hepatitis C, or any serious infection (requiring hospitalisation or parenteral antibiotic therapy) in the past 3 months prior to screening 11. History of malignancy in the past 5 years or suspicion of active malignant disease except treated cutaneous squamous cell or basal cell carcinoma 12. Patients with the following findings at the screening visit that could interfere with cardiac repolarisation: * marked baseline prolongation of QT/QTc interval as measured on ECG (e.g. QTc interval \>450ms); * history of additional risk factors for Torsade de pointe (e.g. heart failure, - hypokalemia, family history of long QT syndrome); * use of concomitant medications that prolong the QT/QTc interval 13. History of drug or alcohol abuse within the past two years 14. Pre-menopausal (last menstruation ≤ 1 year prior to screening) sexually active woman who: * is pregnant or nursing * is of child bearing potential and not practicing acceptable methods of birth control, or does not plan to continue practising an acceptable method throughout the study (acceptable methods of birth control include surgical sterilisation, intrauterine devices, double barrier, male partner sterilisation, but not hormonal contraceptives\*\*) \[A negative serum pregnancy test at screening (Visit 1) and a negative urine test prior to randomisation (Visit 2) are required\] 15. Patient not willing to avoid excess sun exposure during the trial duration 16. Patients who have taken an investigational drug, within the last 4 weeks or 5 half lives (which ever is greater) prior to randomisation \[Patients who have been treated with any investigational antibody or fusion protein within the past 12 weeks before randomisation are excluded\] 17. Known allergy to BIRT 2584 XX or to the excipients used for tablet formulation 18. Body mass index \> 34 kg/m2 at screening