An Efficacy and Safety Study of Intravenous Anifrolumab to Treat Systemic Lupus Erythematosus in Pediatric Participants

A Study to evaluate the PK, PD, efficacy, and safety of Anifrolumab in children with moderate to severe active SLE

This study aims to characterize the pharmacokinetics, pharmacodynamics, efficacy, and safety of Anifrolumab solution for infusion compared with placebo solution for infusion in pediatric participants with severe active systemic lupus erythematosus who are on background standard of care therapy.

The study duration for a participant will be approximately 116 weeks, which includes:

* Screening period of up to 30 days.
* Part A consists of a four-week, single-blind, placebo-controlled, randomised, pharmacokinetic period.
* Part B is a double-blind, placebo-controlled, randomised, safety/efficacy period lasting 48 weeks (for rollover participants from Part A) or 52 weeks (for de novo participants).
* Part C is a 52-week open-label extension period.
* Part D is a safety follow-up period. One safety visit at 12 weeks post last dose.

Eligibility Criteria:
Inclusion Criteria:

* Participant's parent/caregiver/legally authorized representative and participant (if required per local country regulation) capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICF and in this protocol. Informed assent is to be provided by the participant per local country regulation.
* Diagnosis of SLE according to the 2019 European League Against Rheumatism/American College of Rheumatology (EULAR/ACR) criteria.for at least 6 months prior to signing the ICF.
* Participant should meet all of following tuberculosis (TB) criteria:

A. No signs or symptoms of active TB B. No medical history or past physical examinations suggestive of active TB C. No recent contact with a person with active TB or if there has been such contact, referral to a TB specialist for evaluation and initiation of treatment for latent TB, if warranted, prior to the first administration of study intervention in accordance with local SoC D. No history of latent TB without documented completion of treatment prior to initial screening visit

* Female participants of childbearing potential must have a negative pregnancy test at Screening.
* Female participants of childbearing and non-childbearing potential and male participants must adhere to the contraception methods.
* At screening, negative SARS-CoV-2 RT-PCR or rapid antigen test result and no known or suspected COVID-19 infection or exposure between screening and randomization visits.

Exclusion Criteria:

* Known diagnosis of an IFN-mediated autoinflammatory interferonopathy.
* History of, or current diagnosis of, clinically significant non-SLE-related vasculitides.
* In participants aged 11 years and above: history or evidence of suicidal ideation.
* History of any non-SLE disease that has required treatment with oral or parenteral corticosteroids for more than a total of 2 weeks within the last 24 weeks prior to signing the ICF.
* Any positive result on Screening for human immunodeficiency virus.
* Active hepatitis B surface antigen OR hepatitis B core antibody (HBcAb), hepatitis C virus (HCV) antibody and detectable HCV ribonucleic acid (RNA) or any severe case of Herpes Zoster infection.
* Any clinical cytomegalovirus or Epstein-Barr virus infection that has not completely resolved within 12 weeks prior to signing the ICF.
* History of severe COVID-19 infection requiring hospitalization, intensive care unit care, or assisted ventilation or any prior COVID-19 infection with unresolved sequelae. Any mild/asymptomatic COVID-19 infection (laboratory confirmed or suspected based on clinical symptoms).
* Prior use of Anifrolumab.
* Prior treatment with directly acting cytotoxic B-cell depleting therapeutics (eg, rituximab) \< 26 weeks prior to ICF signature.
* Blood transfusion or receipt of blood products except albumin within 4 weeks prior to signing the ICF.