This study provides subjects who complete the BEL113750 study and subjects who complete the open-label extension of HGS1006-C1115 (referred to as C1115) Study in Japan the option of continuing treatment with belimumab (10 mg/kg intravenously every 4 weeks) for those randomized to belimumab, or the option to begin treatment with belimumab for those randomized to placebo, as an add-on to their standard of care SLE therapy.

This is a multicentre, continuation study of belimumab plus standard of care (SOC) in SLE subjects who completed the Phase III BEL113750 protocol in Northeast Asia or who completed the open-label extension of the HGS1006-C1115 protocol in Japan. This study provides subjects who complete the BEL113750 study the option of continuing treatment with belimumab (10 mg/kg intravenously every 4 weeks) for those randomized to belimumab, or the option to begin treatment with belimumab for those randomized to placebo, as an add-on to their SOC SLE therapy. Subjects participating in this continuation protocol will continue to be monitored for safety and efficacy, as measured by the SLE responder index. Subjects who complete 48 weeks of treatment on the BEL113750 study and who meet inclusion/exclusion criteria, and provide informed consent, will be given the option to enter the continuation study. All subjects will receive belimumab 10 mg/kg IV infused over 1 hour every 4 weeks. Subjects recruited into this study will continue to receive treatment with belimumab until such time as belimumab becomes commercially available in a subject's country of participation, or the subject elects to participate in another belimumab continuation study for SLE, or until either the subject's physician withdraws the subject from the study, or upon the decision by the sponsor to discontinue further development of belimumab for SLE.

Inclusion Criteria:

• Have completed the BEL113750 Protocol in Northeast Asia through Week 48 OR have completed the open-label extension of C1115 in Japan.
• Be able to receive the first dose of belimumab for BEL114333 four weeks (minimum of 2 weeks, maximum of 8 weeks) after the last dose in BEL113750 OR be able to receive the first dose of IV belimumab 1 week (plus a 1 week visit window) after the last dose of open-label SC belimumab in C1115..

Exclusion Criteria:

• Have developed clinical evidence of significant, unstable or uncontrolled, acute or chronic diseases not due to SLE (i.e., cardiovascular, pulmonary, hematologic, gastrointestinal, hepatic, renal, neurological, malignancy or infectious diseases), or experienced an adverse event (AE) in the Phase 3 study that could, in the opinion of the principal investigator, put the subject at undue risk.
• Have developed any other medical diseases (e.g., cardiopulmonary), laboratory abnormalities, or conditions (e.g., poor venous access) that in the opinion of the principal investigator, makes the subject unstable for the study.

IPD for this study will be made available via the Clinical Study Data Request site.

IPD is available via the Clinical Study Data Request site (click on the link provided below)

Access is provided after a research proposal is submitted and has received approval from the Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension can be granted, when justified, for up to another 12 months.