A Study of TAK-341 in Treatment of Multiple System Atrophy

Inclusion criteria:

Diagnostic:

1. The participant has a diagnosis of possible or probable MSA using the modifiedGilman et al, 2008 diagnostic criteria.

2. The participant's onset of first MSA symptoms occurred ≤4 years before screening, asassessed by the investigator.

3. Evidence of MSA specific symptoms and deficits as measured by the UMSARS scale.

Exclusion criteria:

Medical History:

1. The participant has any contraindication to study procedures.

Diagnostic Assessments:

1. Presence of confounding diagnosis and/or conditions that could affect participant'ssafety during the study per investigator judgement.

2. The participant's participation in a previous study of a disease-modifying therapy (with proven receipt of active treatment) will compromise the interpretability ofthe data from the present study, per consultation with medical monitor or designee.

Other:

1. The participant has participated in another study investigating active or passive immunization against α-synuclein (αSYN) for progressive disease (PD) or MSA, or has had immunoglobulin G therapy, within 6 months before screening.