This study investigates the safety and tolerability of an investigational medication administered to adults with Multiple System Atrophy (MSA). The study will last approximately 96 weeks for each participant, including a 72-week treatment period and a 24-week follow-up period. Participants will receive the investigational medication through an intrathecal injection, which means it is injected into the space around the spinal cord.

Study procedures include a screening period with a special brain scan called SPECT with DaTscan™ to check for loss of dopamine nerve cells, which is common in neurodegenerative parkinsonism. Participants will be randomly assigned to receive either the investigational medication or a placebo, which is an inactive substance that looks like the investigational medication but does not contain any medicine. The study will monitor the effects of the medication over time.

• Who can participate: Adults diagnosed with probable or possible Multiple System Atrophy (MSA) who can walk unassisted for at least 10 meters may participate. Eligibility includes specific brain scan results showing loss of dopamine nerve terminals.
• Study details: Participants will receive either the investigational medication or a placebo through injections. The study involves monitoring the safety and effects of the treatment over time.
• Study timelines: The study will last approximately 96 weeks.