A Study of Efficacy and Safety of Eltoprazine HCl for Treating Levodopa-induced Dyskinesia in Parkinson's Disease Patients

Inclusion Criteria: * outpatient with idiopathic PD * stable dose of anti-parkinsonian medication for at least four weeks before the Screening Visit * daily levodopa dose ≥300 mg per day divided into at least three doses * treated with levodopa for at least three years prior to study entry * moderate to severely disabling levodopa-induced dyskinesia for at least three months prior to study entry * dyskinesia for, on average, \>25% of the waking day Exclusion Criteria: * inability to use the motion sensors or electronic diaries correctly * surgical treatment for PD, e.g. Deep Brain Stimulation, within the last six months or planned during the study * unstable co-existing psychiatric disease including psychosis, depression or cognitive impairment * Mini Mental State Examination score of \<24 * moderate or severe renal, or severe hepatic, impairment * treatment with selective serotonin re-uptake inhibitors (SSRI) or any combined serotonin-norepinephrine re-uptake inhibitors (SNRI), such as tryptizol, citalopram, escitalopram, sertraline, mianserin, mirtazapin, paroxetin, venlafaxine and St John's Wort, within four weeks prior to the Screening Visit * treatment with medications with the potential for drug-interactions (MAO-A inhibitors, apomorphine, aripiprazol, carbamazepine, clozapine, phenytoin, tramadol, quetiapine, varfaine, valproic acid). Patients taking amantadine will comprise no more than 25% of the study population * current history of a clinically significant and uncontrolled medical condition that may affect the safety of the patient or preclude adequate participation in the study * pregnant or breast-feeding * received any other investigational medicinal product within 30 days of Screening