This is a multicentre non-interventional study aimed at evaluating the real-world effectiveness and safety of ocrelizumab treatment in participants with relapsing multiple sclerosis (RMS) or primary progressive multiple sclerosis (PPMS), who have been prescribed ocrelizumab as per routine practice. This study will use a comprehensive combination of participant reported outcomes and conventional multiple sclerosis (MS) endpoints that measure clinical domains commonly affected by MS (e.g. fatigue, hand function, gait, cognition), and their impact on employment, activities of daily living, quality of life and healthcare resource utilization. The incidence, type, and pattern of serious adverse events (SAEs), and of adverse events (AEs) leading to treatment discontinuation will also be determined.

Inclusion Criteria:

• Must have a definite diagnosis of RMS or PPMS and in whom a decision to initiate ocrelizumab has been taken as part of routine clinical practice
• Must be prescribed ocrelizumab in line with the SmPC
• Must have provided signed informed consent
• Must be able and willing to complete the PROs as per clinical practice

Exclusion Criteria:

• Previously treated with ocrelizumab (including phase II, phase III and phase IIIB clinical trials, local trials and investigator initiated study (IIS) as well as a pre-approval access or compassionate use programmes or local registries that are not compatible with the MuSicalE study design)
• Not receiving ocrelizumab in line with the SmPC

Participants with RMS or PPMS undergoing routine clinical care

For eligible studies, qualified researchers may request access to individual patient level clinical data. See Roche's commitment to transparency of clinical study information here: https://go.roche.com/data\_sharing