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

Inclusion Criteria: * Diagnosed with idiopathic PD. * Adequate duration of levodopa therapy. * Disease duration of at least 5 years or more. * Modified Hoehn \& Yahr Staging with at least 2.5 hours or more in the OFF state. * Candidate for surgical intervention because of disabling motor complications. * UPDRS Part III (total score) of at least 25 in the OFF state. * Unequivocal responsiveness to dopaminergic therapy. * Stable Parkinson's symptoms and medications for at least 4 weeks prior to screening evaluation. * Ability to comprehend and sign the informed consent. * Normal laboratory values prior to surgery. * Medically and mentally capable of undergoing and complying with the surgical procedure and protocol requirements. * Ability to travel to study visits alone or able to designate a caregiver. * Subject agrees to defer any neurological surgery, including deep brain stimulation, until after completing the 12 month study visit (unless recommended by study neurologist). * Approved by the Eligibility Review Committee. Exclusion Criteria: * Atypical or secondary parkinsonism, including but not limited to symptoms believed to be due to trauma, brain tumor, infection, cerebrovascular disease, other neurological disease, or to drugs, chemicals, or toxins. * Presence of dementia as defined by a Mattis Dementia Rating Scale - Second Edition (MDRS-2) score of less than 130 at screening. * Presence or history of psychosis, with the exception of mild, benign hallucinations belie…