A Randomized, Double-Blind, Placebo-Controlled, Phase IIa, Parallel Group, Two Cohort Study to Define the Safety, Tolerability, Clinical and Exploratory Biological Activity of the Chronic Administration of Nilotinib in Participants With Parkinson's Disease

• Idiopathic PD based on the UK Brain Bank diagnostic criteria.

• Any race and either gender, age 40-79

• Able to read and understand English with the capacity to provide voluntary informed consent by signing the informed consent form (ICF)

• Willing to comply with all study procedures including multiple lumbar punctures (LP)

• Must be on a stable regimen of central nervous system acting medications (if applicable) for at least 30 days prior to the baseline visit (e.g., benzodiazepines, antidepressants, hypnotics)

• 6a. Diagnosis of PD duration > 5 year 7a. Hoehn & Yahr scale (H&Y) stage > 2 and < 4 in the ON state 8a. Must be on a stable regimen of PD medications, that includes levodopa, for at least 30 days prior to the screening visit

• a. Treatment with monoamine oxidase B (MAO-B) inhibitors will be allowed provided the dose has been stable for 60 days prior to baseline

• 6b. Diagnosis of PD duration < 3 years 7b. H&Y stage ≤ 2 8b. Participants who are currently NOT receiving symptomatic therapy (ST) (levodopa,dopamine agonists and monoamine oxidase B (MAO-B) inhibitors) and NOT projected to require ST for at least 3 months from enrollment.

• a. Treatment with amantadine or an anticholinergic agent will be allowed provided the dose has been stable for 30 days prior to screening and will remain stable for the duration of the study