A Trial to Test if TEV-56286 is Effective for Treatment of Participants With Multiple System Atrophy

For non-EU: Change From Baseline in the Modified Unified Multiple System Atrophy Rating Scale (UMSARS) Part I Score (excluding item 11)

Timeframe: Baseline to Week 48

The UMSARS is a multidimensional, validated scale for semi-quantitative clinical assessments of MSA participants. Modified UMSARS part I includes all items with the exclusion of item 11. Item scoring is scaled 0-3 using a range of 0 (no impairment) to 3 (severe impairment).

For EU: Change From Baseline in the Total UMSARS Score Part I and Part II Combined

Timeframe: Baseline to Week 48

The UMSARS is comprised of 4 parts: part I, historical review of disease-related impairments, 12 items and part II, motor examination, 14 items. As UMSARS is a unified scale, each item in parts I and II achieves a single score using a range of 0 (no impairment) to 4 (severe impairment).

For non-EU: Change From Baseline in the Total UMSARS Score (Part I and Part II combined)

Timeframe: Baseline to Week 48

For EU: Change From Baseline in the Modified UMSARS part I score (excluding item 11, item scoring rescaled 0-3)

Timeframe: Baseline to Week 48

Change From Baseline in the UMSARS Part 1 Score

Timeframe: Baseline to Week 48

Change From Baseline in Lateral Ventricle Volume Measured by MRI

Timeframe: Baseline to Week 48

Change From Baseline in the Clinical Global Impression - Severity scale (CGI-S)

Timeframe: Baseline to Week 48

The CGI-S scale permits a global evaluation of the participant's current severity of illness on a Likert type scale ranging from 1 to 7, where 1=normal/not at all ill, 2=borderline ill, 3=mildly ill, 4=moderately ill, 5=markedly ill, 6=severely ill, and 7=among the most extremely ill participants

Change From Baseline in the Neurofilament Light Chain (NfL) Concentrations in Cerebrospinal Fluid (CSF)

Timeframe: Baseline to Week 48

Change From Baseline in the Patient Global Impression-Severity Scale (PGI-S)

Timeframe: Baseline to Week 48

The PGI-S scale permits an evaluation of the participant's MSA severity, according to the participant. The PGI-S scale rates the participant's MSA severity on a 5-point Likert type scale ranging from 0 (not severe) to 4 (very severe)

Change From Baseline in the Pons volume measured by MRI

Timeframe: Baseline to Week 48

Change From Baseline in the Cerebellar volume measured by MRI

Timeframe: Baseline to Week 48

Change From Baseline in the UMSARS part II score

Timeframe: Baseline to Week 48

Change From Baseline in the UMSARS part IV score

Timeframe: Baseline to Week 48

Change From Baseline in the Two-minute walk test as part of gait assessment

Timeframe: Baseline to Week 48

Change From Baseline in the Multiple System Atrophy - Quality of Life (MSA-QoL) Score

Timeframe: Baseline to Week 48

The 40-item MSA-QoL questionnaire is self-administered and each item is rated on a Likert type scale (0: No problem) to (4: Extreme problem). It is comprised of 3 subscales relevant to MSA: motor (14 items), non-motor (12 items), and emotional/social (14 items). The MSA-QoL total score is the sum of all the items and lower scores indicate better QoL.

Number of Participants With At Least One Treatment-Emergent Adverse Event (TEAEs)

Timeframe: Up to Week 48

Number of Participants Who Withdraw From the Study Due to an Adverse Event

Timeframe: Up to Week 48

Number of Participants Who Withdraw From Treatment Due to an Adverse Event

Timeframe: Up to Week 48

Number of Participants With At Least One Potentially Clinically Significant Abnormal Vital Sign Value

Timeframe: Up to Week 48

Number of Participants With At Least One Potentially Clinically Significant Laboratory Test Value

Timeframe: Up to Week 48

Number of Participants with at Least One Potentially Clinically Significant Change in 12-lead Electrocardiogram (ECG) Findings

Timeframe: Up to Week 48