A Study to Assess the Safety and Effectiveness of Pridopidine Compared to Placebo in the Treatment of Levodopa-Induced Dyskinesia in Patients With Parkinson's Disease

Inclusion Criteria: * Provides signed informed consent form. * Has clinical diagnosis of Parkinson's Disease (PD). * Has Levodopa-induced dyskinesia (LID). * Patient and/or study partner must demonstrate ability to keep accurate home diary of PD symptoms. * Has stable anti-PD treatments for at least 28 days prior to start of study treatment and kept constant throughout study. * All routine and allowed prescription/non-prescription medications and/or nutritional supplements taken regularly must be at stable dosage for at least 28 days prior to start of study treatment and maintained throughout study. Exclusion Criteria: * Diagnosis of atypical Parkinsonism. * Treatment with dopamine blocking drugs. * History of surgical intervention related to PD, such as deep brain stimulation. * History of severe depression, psychosis or hallucinations within 6 months prior to screening; active suicidal ideation; or suicidal attempt within 5 years prior to screening. * History of certain cancers within 5 years prior to screening. * Significant cardiac event within 12 weeks prior to Baseline or history of certain cardiac arrhythmias. * History of epilepsy or seizures within 5 years prior to screening. * Females who are pregnant or breastfeeding. * Sexually active female patients who are not surgically sterile or at least 2 years postmenopausal prior to screening, and who do not agree to utilize a highly effective hormonal method of contraception in combination with a barrier method, from screening until at least 4 weeks after completion of study treatment. * Male patients not using highly effective contraception or not agreeing to continue highly effective contraception until at least 90 days after the completion of study treatment. * Treatment with any investigational product within 30 days of screening or plans to participate in another clinical study assessing any investigational product during the study. Other protocol-defined inclusion/exclusion criteria could apply.