A Phase I/III Clinical Study to Evaluate NouvNeu001 Injection for Multiple System Atrophy

Inclusion Criteria: * Aged between 30 and 70 years (inclusive), regardless of gender. * The subject understands and agrees to comply with the study procedures and voluntarily provides written informed consent. * Diagnosed with pathologically confirmed, clinically established, or clinically probable Multiple System Atrophy (MSA) according to the 2022 MDS diagnostic criteria. * Current treatments for core MSA symptoms are inadequately controlled. * The duration of MSA-related motor symptoms (parkinsonism and/or cerebellar ataxia) is no more than 5 years. * Ability to walk without human assistance, defined as being able to take at least 10 steps; the use of assistive devices (e.g., a walker or cane) is permitted. * Life expectancy of at least 3 years. * The subject agrees not to participate in any other clinical studies for 24 months following the investigational product administration. Exclusion Criteria: * Neurological diseases/disorders other than Multiple System Atrophy, such as Parkinson's disease, Dementia with Lewy Bodies, Essential Tremor, Progressive Supranuclear Palsy, Spinocerebellar Ataxia, Hereditary Spastic Paraplegia, Corticobasal Degeneration, Vascular Parkinsonism, Normal Pressure Hydrocephalus, or Drug-induced/Postencephalitic Parkinsonism. * Diagnosis of dementia. * Previous or current receipt of other disease-modifying therapies, or participation in clinical trials of other new drugs or novel therapies. * Use of medications within the past 3 months that ma…