A Phase 3, Multi-Center, Randomized, Double-Blind, Placebo-Controlled, 104-Week Study to Evaluate the Efficacy and Safety of Belimumab Administered in Combination With Rituximab to Adult Subjects With Systemic Lupus Erythematosus (SLE)

The purpose of this study is to assess whether co-administration of belimumab and a single cycle of rituximab will optimize treatment with belimumab, which will result in improvements of clinical status with a favorable safety profile, by comparing subjects randomized to belimumab plus rituximab versus belimumab plus rituximab-placebo. Approximately 292 subjects will be randomized in a 1:2:1 ratio to 1 of 3 treatment arms; belimumab plus rituximab-placebo (Arm A, control), belimumab plus rituximab (Arm B, combination), or belimumab plus standard therapy (Arm C, reference). Belimumab will be administered as subcutaneous (SC) and rituximab-placebo or rituximab will be administered by intravenous (IV) infusions. The total duration of the study is for 104 weeks.