This is a Phase 3, multicentre, multinational, randomised, double-blind, placebo-controlled study to evaluate the efficacy and safety of a subcutaneous treatment regimen of anifrolumab versus placebo in participants with moderately to severely active, autoantibody-positive systemic lupus erythematosus (SLE) while receiving standard of care (SOC) treatment. Participants must be taking either 1 or any combination of the following: oral glucocorticoids, antimalarial, and/or immunosuppressants. The study will be performed in adult participants of 18 to 70 years of age.
Approximately 360 participants receiving SOC treatment will be randomised in a 1:1 ratio to receive a fixed subcutaneous dose of anifrolumab or placebo administered once weekly via an accessorized prefilled syringe and with the primary endpoint evaluated at Week 52. Subjects who complete Week 52 may enter into open-label extension (OLE). All patients who enter the OLE Period will receive a fixed subcutaneous dose of anifrolumab for up to 52 weeks. Study intervention will be administered SC via an accessorised prefilled syringe (aPFS).