The non-randomized, open-label phase I study aims to evaluate the safety, tolerability, biodistribution, radiation dosimetry, and pharmacokinetics of SST001 in healthy volunteers, patients with MSA and patients with PD.

SST001 is a 18F-labeled PET tracer designed to detect alpha-synuclein (α-Syn) pathology in vivo, a hallmark of PD and MSA. The non-randomized, open-label phase I study aims to evaluate the safety, tolerability, biodistribution, radiation dosimetry, and pharmacokinetics of SST001 in healthy volunteers, patients with MSA and patients with PD.

Inclusion Criteria:

• Sign the informed consent form approved by IEC.
• Male or female participants aged ≥40 years old.
• Adequate organ functions.
• Proper contraception methods.
• Willingness to follow the study procedures.
• Additional inclusion criteria for healthy volunteers: Good health status; no history of motor disorders or cognitive disorders.
• Additional inclusion criteria for MSA: Diagnosed with clinically established or clinically probable MSA according to the MDS MSA criteria (2022). If previously treated, the treatment regimen for MSA must have been stable for at least 4 weeks with no planned adjustments in the near term.
• Additional inclusion criteria for PD: Diagnosed with clinically established or clinically probable PD according to the MDS PD criteria (2015). If previously treated, the treatment regimen for PD must have been stable for at least 4 weeks with no planned adjustments in the near term.

Exclusion Criteria:

• Being pregnant or lactating.
• History of other severe neurological disorders.
• History of serious or uncontrolled medical condition.
• Active HBV/HCV/HIV infection, etc.
• History of abuse of drugs or alcohol within 1 year.
• Allergy to the study drug.
• Intolerance to PET/CT or MRI (e.g. claustrophobia).
• Any interventional clinical studies within 30 days.
• Radiation exposure dose exceeding 50 mSv/year.
• Prior therapy targeting α-Syn.
• Other ineligible conditions for this study.