Safety and Efficacy of Multiple Doses of BT061 in Patients With Moderate to Severe Chronic Plaque Psoriasis

Inclusion Criteria: * Male and female patients with moderate, moderate to severe or severe chronic plaque psoriasis diagnosed ≥ 12 months prior to Screening. * BSA (Body surface area) involvement \> 10% for more than 6 months. * PASI ≥10. * Age ≥ 18 to ≤ 75 years. * Body mass index (BMI) of 18-30 kg/m2 with a body weight between 50 and 130 kg. Exclusion Criteria: * Erythrodermic, guttate or palmar pustular psoriasis (mixed forms may be admissible if chronic plaque psoriasis clearly remains the predominant diagnosis * Treatment with a biological within less than 30 days or within less than 5 half-lives of the respective compound prior to administration of BT061/placebo. * Serious local (e.g. abscess) or systemic infection (e.g. pneumonia, septicaemia) within 3 months prior to the administration of BT061 or placebo. * Presence or history of clinically significant immune deficiency or autoimmune disease (except psoriasis). * Positive diagnosis for acute or chronic infections (i.e. Hepatitis C Virus \[HCV\], Hepatitis B Virus \[HBV\], Human Immunodeficiency Virus \[HIV\]) at Screening visit.