A Phase 2 Study of ONO-2808 in Patients With Multiple System Atrophy

This study will consist of a core part, an extension part, and an additional extension part. The purpose of the core part is to evaluate 3 doses of ONO-2808 compared to placebo in MSA patients, including: 1) safety and tolerability, 2) pharmacokinetics, and 3) changes in clinical outcome assessments (COA) and biomarkers considered to be related to the pharmacodynamics and potential efficacy of ONO-2808. The purpose of the extension part and the additional extension part is to evaluate 3 doses of ONO-2808 in MSA patients, including: 1) safety and tolerability and 2) changes in COAs and biomarkers considered to be related to the pharmacodynamics and potential efficacy of ONO-2808.