The purpose of this study is to assess the safety, tolerability, pharmacokinetics (PK) and, pharmacodynamics (PD) of subcutaneously administered RO7845860 in participants with relapsing multiple sclerosis (RMS).
Diagnosis of RMS (i.e., relapsing-remitting multiple sclerosis [RRMS] or a secondary progressive multiple sclerosis [SPMS] where patients still experience relapses) in accordance with the revised 2017 McDonald Criteria.
No relapse for 30 days prior to screening and neurologically stable with no relapse during screening.
Expanded Disability Status Scale (EDSS) score at screening (historical EDSS not older than 6 months may be used), from 0 to 6.5 inclusive.
From Part 2 onwards,
History of primary progressive multiple sclerosis (PPMS) at screening.
CD4 levels below lower limit of normal (LLN)
Absolute neutrophil count (ANC) levels below LLN
Serum immunoglobulin G (IgG) levels below LLN