A Study to Evaluate the Efficacy, Safety, Pharmacokinetics, and Pharmacodynamics of Satralizumab in Participants With Myelin Oligodendrocyte Glycoprotein Antibody-associated Disease

Inclusion criteria

• Participants who are aged >=12 years at the time of signing Informed Consent Form
• Confirmed diagnosis of MOGAD with a history of >=1 MOGAD relapse in the 12 months prior to screening or >=2 attacks in the 24 months prior to screening
• Expanded Disability Status Scale (EDSS) score of 0-6.5 at screening
• High-contrast visual acuity (HCVA) better than 20/800 in each eye at screening
• Participants receiving either no or ongoing chronic immunosuppressant treatment (IST) for MOGAD at the time of screening
• For women of childbearing potential: participants who agree to remain abstinent or use adequate contraception during the treatment period and for at least 3 months after the final dose of satralizumab

Exclusion criteria

• Presence of aquaporin-4-antibodies immunoglobin G (AQP4-IgG) in the serum
• History of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis
• Any concomitant disease other than MOGAD that may require treatment with ISTs or oral corticosteroids (OCS) or intravenous (IV) corticosteroids at doses > 20 milligrams (mg) prednisone equivalent per day for >21 days during the study
• Participants who are pregnant or breastfeeding, or intending to become pregnant during the study or within 3 months after the final dose of satralizumab
• Participants with active or presence of recurrent bacterial, viral, fungal, mycobacterial infection, or other infection at baseline
• Participants with evidence of latent or active tuberculosis (excluding patients receiving chemoprophylaxis for latent tuberculosis infection)
• Participants with positive screening tests for hepatitis B and C
• Receipt of live or live attenuated vaccine within 6 weeks prior to baseline
• History of severe allergic reaction to a biologic agent