Open-label Study of Belimumab Plus Standard Therapy in Chinese Pediatric Participants With Active Systemic Lupus Erythematosus (SLE)

Inclusion criteria

• Participants have or have had in series, 4 or more of the American College of Rheumatology (ACR) 11 criteria for the classification of SLE.
• Participant's age is 5 to 17 years at the time of informed consent.
• Have active SLE disease defined as a SELENA SLEDAI score >= 8 at screening (SELENA SLEDAI scoring).
• Have unequivocally positive autoantibody test results defined as an anti-nuclear antibody (ANA) titer >=1:80 and/or a positive anti-Double stranded deoxyribonucleic acid (dsDNA) serum antibody test.
• Are on a stable SLE therapy at Baseline. The stable treatment at Baseline consists of corticosteroids, anti-malarials, immunosuppressive/immunomodulatory agents and Non-steroidal anti-inflammatory drugs (NSAIDs), alone or in combination, at a fixed dose for a period of at least 30 days prior to Day 0.
• No gender restriction. Contraceptive use by men or women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.
• The investigator, or a person designated by the investigator, will obtain written informed assent from each study participant or the participant's legally acceptable representative, parent(s), or legal guardian and the participant's assent, when applicable, before any study-specific activity is performed. The investigator will retain the original copy of each participant's signed assent document.

Exclusion Criteria

• Have an estimated glomerular filtration rate (eGFR) as calculated by Schwartz Formula of less than 30 mL/minutes.
• Have acute severe nephritis defined as a significant worsening of renal disease (for example [e.g.], the presence of urinary sediments and other lab abnormalities) that, in the opinion of the study investigator, may lead to the participant requiring induction therapy with intravenous (IV) cyclophosphamide, Mycophenolate mofetil (MMF) or high dose corticosteroids during the first 6 months of the study.
• Have a history of a major organ transplant (e.g., heart, lung, kidney, liver) or hematopoietic stem cell/marrow transplant.
• Have clinical evidence of significant, unstable or uncontrolled, acute or chronic diseases not due to SLE (cardiovascular, pulmonary, hematologic, gastrointestinal, hepatic, renal, neurological, malignancy or infectious diseases) which, in the opinion of the investigator, could confound the results of the study or put the participant at undue risk.
• Have a planned surgical procedure or a history of any other medical disease (e.g., cardiopulmonary), laboratory abnormality, or condition (e.g., poor venous access) that, in the opinion of the investigator, makes the participant unsuitable for the study.
• Have a history of malignant neoplasm within the last 5 years.
• Have a history of a primary immunodeficiency.
• Have an Immunoglobulin A (IgA) deficiency (IgA level less than [ 1.5 mg/kilogram/day) or any intramuscular or intravenous steroid injection.
• Have received a live or live-attenuated vaccine within 30 days of Day 0.
• Have active central nervous system (CNS) lupus (including seizures, psychosis, organic brain syndrome, cerebrovascular accident [CVA], cerebritis or CNS vasculitis) requiring therapeutic intervention within 60 days of Day 0.
• Have required renal replacement therapy (e.g., hemodialysis, peritoneal dialysis) within 90 days of Day 0 or be currently on renal replacement therapy.
• Participation in an interventional clinical study either concurrently or within 6 months of screening. Participation in an observational study may be permitted.
• Have a historically positive test or test positive at screening for Human immunodeficiency virus (HIV) antibody.
• Evidence of active or latent tuberculosis (TB) as documented by medical history and examination, chest X-rays (posteroanterior) and a positive (not indeterminate) QuantiFERON-TB Gold Plus test.
• Hepatitis B: Serologic evidence of Hepatitis B (HB) infection defined as Hepatitis B surface antigen p