Terminated prior to completing enrollment goals due to COVID-related difficulties in recruiting patients

This open-label study is designed to assess the long-term safety and tolerability of dipraglurant in PD patients for up to 52 weeks (at doses of 150-300 mg per day) for patients that have completed an Addex sponsored double-blind clinical trial of dipraglurant.

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