RecruitingPhase 1Drug trialA Study to Investigate the Safety, Tolerability, and Processing by the Body of Intravenous and Subcutaneous RO7121932 Administration in Participants With Multiple SclerosisThe primary purpose of the study is to evaluate the safety and tolerability of a single-ascending intravenous (IV) dose (Part 1), a single-ascending subcutaneous (SC) dose (Part 2), and multiple ascending SC doses (Part 3) of RO7121932 in participants with multiple sclerosis (MS).