• Participant must be ≥18 to ≤89 years of age, at the time of signing the informed consent

• Confirmed diagnosis of MOG-AD consistent with published diagnostic criteria for MOG-AD

• Participant has history of relapsing MOG-AD with at least 1 documented relapse over the last 12 months and a documented positive serum MOG Ab test using a cell-based assay (CBA) within 6 months prior to randomization

• Participant must be clinically stable at the time of the Screening Visit and during the Screening Period