BIIB023 Proof-of-Concept Study in Participants With Lupus Nephritis

A Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate the Efficacy, Safety, and Tolerability of BIIB023 in Subjects With Lupus Nephritis

The primary objective of the study is to assess the efficacy of BIIB023 as an add-on treatment to background therapy compared with placebo in combination with background therapy in the treatment of participants with active, biopsy-proven lupus nephritis. The secondary objectives of this study are to assess the safety and tolerability of BIIB023 compared with placebo in this study population.

Participants who complete this study through Week 52 will be offered the option to enter an Extension study under a separate protocol 211LE202 (NCT0193089).

Key Inclusion Criteria:

• Documented diagnosis of systemic lupus erythematosus (SLE) according to current American College of Rheumatology (ACR) criteria. At least 4 ACR criteria must be documented, 1 of which must be a positive antinuclear antibody (ANA), anti Sm, or anti dsDNA antibody.
• Diagnosis of International Society of Nephrology/Renal Pathology Society (ISN/RPS) 2003 Class III or IV lupus nephritis with either active or active/chronic disease, confirmed by biopsy within 3 months prior to Screening. Participants are permitted to have co existing Class V lupus nephritis. If a renal biopsy has not been performed within 3 months of the Screening Visit, one can be performed during the Screening Period after all other eligibility criteria have been confirmed. The local histological diagnosis must be confirmed by the central study pathologist.
• Must have proteinuria at Screening (from a 24 hour urine sample collection) defined as urinary protein:creatinine ratio (uPCR) >1.0 mg/mg.

Key Exclusion Criteria:

• Retinitis, poorly-controlled seizure disorder, acute confusional state, myelitis, stroke or stroke syndrome, cerebellar ataxia, or dementia that is currently active and resulting from SLE at Screening
• Estimated glomerular filtration rate (eGFR) <30 mL/min per 1.73 m^2 (calculated using the abbreviated Modification of Diet in Renal Disease equation) or the presence of oliguria or end-stage renal disease requiring dialysis or transplantation
• Subjects requiring dialysis within 12 months prior to Screening
• History of renal transplant
• Treatment with any biologic B-cell-depleting therapy (e.g., anti-CD20 [rituximab], anti-CD22 [epratuzumab], anti-BLyS/B-cell activating factor [e.g., briobacept, belimumab] therapy), or TACI-Ig within 12 months prior to Run-in Day 1.

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.