Phase 3 Extension Study to Evaluate Long-term Safety of Ianalumab in Participants With Systemic Lupus Erythematosus (SIRIUS-SLE Extension).

Key Inclusion Criteria: * Signed informed consent prior to participation in the extension study. Parent or legal guardian's signed informed consent and child's assent, if appropriate, are required before any assessment is performed for participants \<18 years of age. Of note, if the participant reaches age of consent (age as per local law) during the study, they will also need to sign the corresponding study Informed Consent Form (ICF) at the next study visit. * Participants must have participated in either one of the two SIRIUS-SLE core studies, CVAY736F12301 or CVAY736F12302, and have completed the treatment period through Week 60 without treatment discontinuation. * In the judgement of the investigator, participants must be expected to clinically benefit from continued study treatment. Key Exclusion Criteria: * Use of prohibited therapies. * Active viral, bacterial or other infections requiring intravenous or intramuscular treatment for clinically significant infection which in the opinion of the investigator will place the participant at risk for participation. * Plans for administration of live vaccines during the study period. * Pregnant or nursing (lactating) women. * Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, refusing or unable to use highly effective methods of contraception while on study treatment and for 6 months after stopping of study drug (or longer if required by concomitant medications). * United States (and other countries, if locally required): sexually active males, unless they agree to use barrier protection during intercourse with women of child-bearing potential while taking study treatment. Other protocol-defined inclusion/exclusion criteria may apply.