Proof-of-Concept Study With BT063 in Subjects With Systemic Lupus Erythematosus

Inclusion Criteria: * Eligible male and female subjects, Age ≥ 18 and ≤ 75 years with Body mass index ≥ 18 and ≤ 35 kg/m2 at screening visit * Diagnosed SLE (defined by ≥ 4 of the 11 American College of Rheumatology (ACR) classification criteria for SLE) for at least 3 months before screening * Moderate to severe SLE disease activity demonstrated by SLEDAI-2K total score ≥ 6, including skin and joint involvement * CLASI Activity score ≥ 5 or at least 5 of 66/68 joints with pain and signs of inflammation * Positive anti-nuclear antibodies (ANA) test at screening * No change in concomitant medication for SLE activity maintenance and symptom control regarding type of medication and dose level for at least 8 weeks prior to baseline (for steroids and NSAIDs/pain medication 2 weeks) * Normal electrocardiogram (ECG) Exclusion Criteria: * Active, severe neuropsychiatric SLE defined as any neuropsychiatric element scoring BILAG level A disease or lupus nephritis * Diagnosed psoriasis * Presence or history of malignancy within the previous 5 years * Systemic antibiotic treatment within 2 weeks before baseline visit * A positive diagnosis for viral hepatitis B or hepatitis C or Human immunodeficiency virus (HIV) or tested positive for tuberculosis as assessed or recent infection with Herpes Zoster or Herpes Simplex (Type 1 and Type 2), Epstein-Barr virus (EBV) or cytomegalovirus (CMV) infection or reactivation at screening * Clinically significant hematologic abnormalities attributed to SLE: Haemoglobin \< 8 g/dL; Platelets \< 50 E9/L; Leucocytes \< 2.0 E9/L * Active or history of inflammatory bowel disease (including active or history of colitis) * Received the following medications: - Rituximab within the last 48 weeks before screening - Belimumab within the last 12 weeks before screening - IV immunoglobulin (Ig) within the last 12 weeks before screening - Intramuscular (IM) or intra-articular glucocorticosteroids within the last 4 weeks before screening - IV cyclophosphamide within the last 6 months before screening - IV glucocorticosteroids (pulse therapy) within the last 6 months before screening * Pregnant or nursing women or women who intend to become pregnant * Known intolerance to immunoglobulins or comparable substances (e.g., significant vaccination reaction) * Known intolerance to proteins of human origin * History of clinically significant drug or alcohol abuse within the last 12 months