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