Safety and Efficacy Study of VY-AADC01 for Advanced Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder involving loss of dopamine producing neurons located in the striatum. Levodopa is the primary treatment used to treat Parkinson's disease, which converts to dopamine by the enzyme (protein) Aromatic L-Amino Acid Decarboxylase (AADC). As PD progresses, the amount of AADC levels in the brain decreases, and in turn, reduces the amount of dopamine that is produced with each dose of levodopa. The primary objective of this study is to evaluate the safety of increasing AADC levels, via gene delivery. The investigational drug, termed VY-AADC-01, will be injected directly into the striatum during a neurosurgical procedure that is performed with real-time MRI imaging to monitor delivery. Participants will continue to take their Parkinson medications, including levodopa while participating in this study. The safety and potential clinical responses to VY-AADC-01 will be assessed by repeated clinical evaluations of Parkinson's disease, treatment review phone calls, cognitive tests, laboratory blood tests, patient reported outcomes scales, patient diaries, collection of adverse events, and neuro-imaging. Clinical evaluations will be performed over a 3 year follow-up period.