A Study to Evaluate the Treatment Outcomes of Subcutaneous Anifrolumab in Immunosuppressant-naïve and Biologic-naïve Systemic Lupus Erythematosus

In this study, approximately 275 participants will be enrolled and the study duration will be up to approximately 69 weeks, including: A Screening Period lasting up to 35 days and A 52-week treatment period. Also, participants not continuing treatment with any preparation of anifrolumab after Week 52 will have additional safety follow up 12 weeks after last dose of anifrolumab. Anifrolumab will be administered SC via an aPFS during the 52-week Study. The study population will comprise participants taking antimalarial with or without GCs (there is a recruitment cap of 50% of patients not on GC at baseline) who are IS-naïve and biologic-naïve and are not meeting LLDAS criteria, described by the following cohorts: * Clinical SLEDAI 2K ≥4 points regardless of GC dose and disease duration. * Clinical SLEDAI-2K \< 4 with GC ≥ 7.5 mg/day for \> 5 weeks. After receiving the first dose of anifrolumab (week 0), the participant is allowed to increase the GC dose up until week 4, based on the investigator's recommendation. Between week 5 and week 40, participants taking \>5 mg/day GC dose at study entry will attempt a protocolized taper to 5 mg/day over 12 weeks. Participants achieving DORIS remission for 2 consecutive visits will attempt complete withdrawal of GC following a 12-week tapering regimen. Starting week 41 until the end of the study (week 52), there will be no further reduction of GC dose.