Safinamide as Add-On Therapy in Patients With Early Idiopathic Parkinson's Disease Treated With a Stable Dose of a Single Dopamine Agonist

Inclusion Criteria: * Patients with a diagnosis of idiopathic Parkinson's disease of less than 5 years duration, and a Hoehn and Yahr Stage of I to III, * who were receiving treatment with a single dopamine agonist at a stable dose for at least 4 weeks prior to Visit 1 (Screening). Exclusion Criteria: * Patients with medical conditions and/or taking concomitant medications that would have put them at risk, interfered with the study evaluations, or made them unable to complete the requirements of the study; * patients with a diagnosis or recent history of substance abuse, * a history of psychosis, * who were depressed, * had evidence of dementia or cognitive dysfunction, * or who were experiencing end of dose wearing-off; * female patients of childbearing potential; * patients who have previously received safinamide.