A Study to Evaluate the Efficacy and Safety of Safinamide, as add-on Therapy, in Idiopathic Chinese Parkinson's Disease (PD) Patients With Motor Fluctuations Treated With Stable Doses of Levodopa

Inclusion Criteria

• Male or female patients aged ≥18 years old.
• Chinese ethnicity.
• Able to understand and willing to provide written informed consent.
• Able to maintain an accurate and complete 24-hour diary with the help of a caregiver.
• Diagnosis of idiopathic Parkinson's Disease (IPD) using the United Kingdom Parkinson's Disease Society Brain Bank criteria of more than 3 years duration.
• Be levodopa responsive and receiving treatment with stable daily doses of oral L-dopa, with or without benserazide/carbidopa, with or without addition of a catechol-O-methyltransferase (COMT) inhibitor and may be receiving concomitant treatment with stable doses of dopamine agonists, anticholinergics and/or amantadine for at least 4 weeks prior to the screening visit.
• A Hoehn and Yahr stage between 1-4 inclusive during the "ON" phase.
• Experiencing motor fluctuations with a minimum of 1.5 hours/day of "OFF" time during the day (excluding morning akinesia), based on historical data.
• If female, be post-menopausal for at least one year or have undergone hysterectomy or, if of child-bearing potential, must have a negative pregnancy test, must not be breast-feeding nor become pregnant during the study and must use adequate contraception for 1 month prior to randomisation and for up to 1 month after the last dose of study drug. Adequate contraception is defined as:
• Hormonal oral, implantable, transdermal, or injectable contraceptives or a non-hormonal intrauterine device or female condom with spermicide or contraceptive sponge with spermicide or diaphragm with spermicide or cervical cap with spermicide for at least 2 months before the screening visit;
• a male sexual partner who agrees to use a male condom with spermicide or a sterile sexual partner . For all women of child-bearing potential, urine pregnancy test result at screening must be negative.

For all women of child-bearing potential, urine pregnancy test result at screening must be negative.

Exclusion Criteria

• Any form of Parkinsonism other than IPD.
• Diagnosis of chronic migraine (>15 days per month) or cancer pain.
• L-dopa infusion.
• Hoehn and Yahr stage 5 during the "ON" phase.
• If female, pregnancy or breast-feeding.
• Neurosurgical intervention of PD or stereotactic brain surgery.
• Severe peak dose or biphasic dyskinesia, unpredictable or widely swinging fluctuations.
• History of major depression or other clinically significant psychotic disorder which compromise the ability to provide the informed consent or to participate to the study.
• Drug and/or alcohol abuse within 12 months prior to the screening visit.
• History of dementia or severe cognitive dysfunction.
• Use of any investigational drug or device within 30 days prior to screening or 5 half-lives, whichever is the longest, or during the study.
• Allergy/sensitivity or contraindications to the investigational medicinal products (IMPs) or their excipients, to anticonvulsants or to anti-Parkinson drugs.
• Any clinically significant condition (including laboratory values) which, in the opinion of the Investigator, would not be compatible with study participation or represent a risk for patients while in the study.
• Moderate or severe liver failure using the Child-Pugh classification score, or human immunodeficiency virus (HIV) infection.
• Treatment with monoamine oxidase inhibitors (MAOIs), pethidine, opiates, opioids, fluoxetine, fluvoxamine in the 4 weeks prior to the screening visit. These drugs are not allowed throughout the study and up 2 weeks after the last dose of study drug.
• Ophthalmologic history including any of the following conditions: albinism, uveitis, retinitis pigmentosa, retinal degeneration, active retinopathy, severe progressive diabetic retinopathy, inherited retinopathy or family history of hereditary retinal disease.