This is a double-blind, randomized, placebo-controlled, parallel-group, dose ranging study, to explore the efficacy, safety, tolerability and pharmacokinetic (PK) of low and high dose of CPL500036 an phosphodiesterase 10A (PDE10A) inhibitor in Parkinson's disease patients with levodopa induced dyskinesia (LID) when administered for 28 days. The study will be conducted at multiple Clinical Sites. Approximately 108 patients will be randomized at 1:1:1 ratio to receive low or high dose of CPL500036 or placebo in a blinded manner, once daily for 28 days (Day 1 to Day 28). The study will comprise of Screening, Baseline (a 4-day in-house period), a Treatment Period and a Follow-Up Period. The patients will be discharged from clinical units during the Treatment Period. Approximately 30% of the patients (11 patients in each of the 3 treatment groups) will undergo extensive PK blood sampling during the Treatment Period and the remaining 70% of the patients will undergo sparse PK blood sampling. Patients from extensive PK blood sampling will be discharged from the Clinical Site on Day 8 and Day 1 for patients from sparse PK blood sampling group respectively.
The aim of the study is to determine potential anti-dyskinetic properties of CPL500036 (PDE10A inhibitor) in Parkinson disease patients suffering from levodopa Induced dyskinesia. The study is to determine the efficacy and dose response of two CPL500036 doses, compared with placebo.