An Open-label Safety and Efficacy Study of VY-AADC01 Administered by MRI-Guided Convective Infusion Using a Posterior Trajectory Into the Putamen of Participants With Parkinson’s Disease With Fluctuating Responses to Levodopa

– 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
believed in the judgment of the Investigator to be related to Parkinson’s medications.

– Presence of severe depression, as indicated by a BDI-II score greater than 28, or a
history of a major affective disorder within 5 years of screening evaluation.

– Active suicidal ideation or suicide attempt within 5 years of screening evaluation.

– History of substance abuse within 2 years of screening evaluation.

– Brain imaging abnormalities in the striatum or other regions that would substantially
increase risk of surgery.

– Contraindication to MRI and/or gadoteridol.

– Coagulopathy or inability to temporarily stop any anticoagulation or antiplatelet
therapy prior to surgery.

– Prior brain surgery including lesioning procedures, deep brain stimulation, infusion
therapies or any other brain surgery.

– Prior gene transfer.

– History of stroke, poorly controlled or significant cardiovascular disease, diabetes,
or any other acute or chronic medical condition.

– History of malignancy other than treated carcinoma in situ within 3 years of screening
evaluation.

– Clinically apparent or laboratory-detected infection.

– Prior or current treatment with any investigational agent within 2 months of screening
evaluation.

– Inability to comply with the procedures of the protocol, including completion of paper
Parkinson’s disease diaries, frequent and prolonged study visits including off
medication visits, and travel.

– Chronic immunosuppressive therapy, including chronic steroids, immunotherapy,
cytotoxic therapy, and chemotherapy.

– Any serious medical condition or abnormal finding on physical examination or
laboratory investigation that would substantially increase the risks of the study
procedures.

– Any medical condition that is likely to lead to disability during the course of the
study and interfere with or confound study assessments.

– Pregnant and lactating women.

– Male or female with reproductive capacity who is unwilling to use barrier
contraception for 6 months after surgery.

– Plans to receive any vaccination within 30 days of surgery.

– Any factors, medical or social, which would likely cause the participant to be unable
to follow the study protocol, including geographical inaccessibility.

– Ongoing treatments including neuroleptic medications, apomorphine, or levodopa
infusion therapy (Duopa®).

– Plans to participate in any other therapeutic intervention study within 12 months
after surgery.