Study participants receive standard therapy for SLE in addition to receiving the study drug, either placebo (no active medicine) or belimumab. The controlled period of the study is 52 weeks. The random assignment in this study is "1 to 1" which means that participants have an equal chance of receiving belimumab or placebo. After completion of the 52-week study period, participants will be contacted by phone annually for 4 more years to assess health status.
Following the 52-week controlled period, participants who wish to continue treatment with belimumab may be able to do so by being prescribed commercially available belimumab. If belimumab is not commercially available in the participant's country, the participant may be able to receive belimumab under a separate continuation protocol.
