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

The purpose of this study is to determine if nilotinib is safe, if it can be tolerated by patients with Parkinson's disease (PD) and to learn if nilotinib has the possibility of effectively treating PD symptoms. Nilotinib has been approved by the Food and Drug Administration (FDA) to treat certain types of cancer (leukemia) but is considered investigational in this study because it has not been approved for treating PD. Twenty-five sites will enroll participants into 2 cohorts,approximately 75 in Cohort 1 and 60 in Cohort 2. Participants with moderate to advanced PD symptoms will be enrolled in Cohort 1, randomly assigned to take nilotinib (150 mg or 300mg) or placebo, and will complete 13 in-person study visits over 8.5 months.

The results from Cohort 1 will determine if either dose of nilotinib (150mg or 300 mg) is safe and tolerable enough to move forward and evaluate in Cohort 2. If either dose is found to be safe and tolerable, participants with early PD will be enrolled into Cohort 2.

Participants in Cohort 2 will be randomly assigned to either nilotinib (dose to be determined from Cohort 1 results) or placebo and will complete 17 in-person visits over 14.5 months. For both cohorts, the study visits will include clinical assessment of motor, neuropsychiatric and cognitive testing as well as collection of blood and cerebral spinal fluid, collected by lumbar puncture.

This study will also evaluate if nilotinib can help improve motor symptoms associated with PD. All participants in Cohort 1 and participants in Cohort 2 who have started PD medications will have an assessment of the motor exam (Part III) in a practically defined OFF state (12 hours post dose) and ON state (at least one-hour post dose).