A Study to Investigate Pharmacokinetics, Pharmacodynamics, and Safety of Subcutaneous Anifrolumab in Pediatric Participants 5 to < 18 Years of Age With Systemic Lupus Erythematosus

This is an open-label, multicenter study. The study includes - * Screening Period of up to 35 days * Period A (12-week, open-label treatment period) * Period B (a possible 12-week dosing regimen adjustment period, if required) * Treatment Extension Period (up-to-40-week, optional) * Period C (a 12-week safety follow-up period) The study intervention (anifrolumab) will be administered subcutaneously using an accessorized pre-filled syringe (APFS) in 2 cohorts.