The purpose of this study is to evaluate whether MSA-01 slows the progression of multiple system atrophy (MSA) and to assess its safety.

The primary question is:

• Does MSA-01 slow the progression of motor impairment as measured by UMSARS Part 2 score?

Participants will be randomly assigned to receive MSA-01 or placebo for 12 months. They will attend regular clinic visits for safety and efficacy assessments and record their medication use and any side effects in a diary.

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder with no established disease-modifying treatment. Evidence suggests that coenzyme Q10 (CoQ10) deficiency may contribute to MSA pathophysiology. MSA-01 (ubiquinol), a highly bioavailable form of CoQ10, demonstrated acceptable safety and potential efficacy in a prior phase II trial.

This is a multicenter, randomized, double-blind, placebo-controlled phase III study evaluating the efficacy and safety of MSA-01 in patients with MSA. Approximately 140 participants will be randomized 1:1 to receive oral MSA-01 or placebo for 52 weeks.

The primary endpoint is the change from baseline to Week 52 in the Unified Multiple System Atrophy Rating Scale (UMSARS) Part 2 score. Secondary endpoints include additional clinical scales and safety assessments. Efficacy will be analyzed using a mixed-effects model for repeated measures. The study aims to determine whether MSA-01 slows clinical progression compared with placebo while maintaining an acceptable safety profile.

Inclusion Criteria:

At the time of informed consent

1. Patients diagnosed as 'clinically established' or 'clinically probable' MSA based on the revised MSA diagnostic criteria of the Movement Disorder Society (MDS).

2. Patients who are able to walk independently or with the use of assistive devices.

3. Patients who are able to attend outpatient visits at the participating study site.

   At the start of study drug administration

4. Patients who are able to discontinue the use of CoQ10 supplements.

Exclusion Criteria:

1. Patients with severe neurological disorders, other progressive movement disorders, or cognitive impairment.
2. Patients with severe liver disease.
3. Patients with a known history of hypersensitivity to any component of the investigational drug.
4. Pregnant women, breastfeeding women, or women who may be pregnant.
5. Patients who have previously participated in a clinical trial of MSA-01.