Open-label Safety Study of Dipraglurant (ADX48621) in Patients With Parkinson's Disease Receiving Levodopa-based Therapy

Inclusion Criteria: * Completed an Addex randomized controlled study of dipraglurant and, in the judgement of the Investigator, may benefit from open-label treatment * Able to take study drug 3 times daily and no less than 3 hours apart * Must be taking levodopa not less than 3 times daily throughout the study * Must maintain stable regimen of antiparkinson's medications (including levodopa) and be willing to continue the same doses and regimens for the first 4 weeks of the study Exclusion Criteria: * Patient is judged by the Investigator to be inappropriate for the study (for reasons such as, but not limited to, significant noncompliance in the Addex randomized controlled study of dipraglurant) * Use of amantadine or amantadine ER throughout the study * Use of memantine throughout the study * Any use of marijuana or other cannabis/cannabinoid products for the first 4 weeks of study participation Other protocol-defined inclusion and exclusion criteria may apply