This is a double-blind, randomized, placebo controlled, parallel group, dose ranging study to explore the efficacy, safety, tolerability and PK of 2 different doses of CPL500036 (phosphodiesterase 10A [PDE10A] inhibitor) in patients with an acute exacerbation of schizophrenia. Approximately 165 patients will be randomized at a 1:1:1 ratio and will be dosed with 20 mg CPL500036, 40 mg CPL500036 or placebo once daily for 28 consecutive days (Day 1 to Day 28). Patients will remain in house for the duration of the Treatment Period. The study will comprise of a Screening Period (that will include a prior Medication Washout Period), a Treatment Period and a Follow-up Period. After discharge from the Clinical Unit, patients will return to the Clinical Unit for 2 once weekly Follow-up Visits. Approximately 30% of the patients (17 patients in each of the 3 treatment groups) will undergo extensive PK sampling during the Treatment Period, and the remaining 70% of the patients will only undergo sparse PK sampling.
The purpose of this study is to determine the efficacy, safety, tolerability and pharmacokinetics (PK) properties of CPL500036 compound (PDE10a inhibitor) in patients with an acute exacerbation of schizophrenia after 28 days of administration..