Efficacy, Safety, and Tolerability of E2007 in Levodopa Treated Parkinson's Disease Patients With Motor Fluctuations

INCLUSION CRITERIA: 1. Male or female patients with idiopathic Parkinson's Disease fulfilling the United Kingdom (UK) Parkinson's disease Society Brain Bank diagnostic criteria 7, with a good response to levodopa. 2. Patients must have been diagnosed with idiopathic PD at \> 30 years of age. 3. Patients must have predictable motor fluctuations of the wearing "OFF" type. 4. Patients must rate between II-IV on the Hoehn \& Yahr scale when in an "OFF" state. 5. Patients must be taking optimized levodopa therapy. EXCLUSION CRITERIA: 1. Pregnant or lactating women. 2. Women of child bearing potential unless infertile (including surgically sterile) or practicing effective contraception (eg, abstinence, intrauterine device or barrier method plus hormonal method). These patients must have a negative serum beta-human chorionic gonadotrophin (B-HCG) test at the Screening visit, and a negative urine pregnancy test at the Baseline visit (Day 0). These patients must also be willing to remain on their current form of contraception for the duration of the study. Postmenopausal women may be recruited but must be amenorrheic for at least one year to be considered of non-child bearing potential as determined by the Investigator. 3. Patients with a past or present history of drug or alcohol abuse as per Diagnostic and Statistical Manual - 4th edition (DSM IV) criteria. 4. Patients with a past (within one year) or present history of suicidal ideation or suicide attempts. 5. Patients with unstable abnormalities of the hepatic, renal, cardiovascular, respiratory, gastro-intestinal, hematological, endocrine or metabolic systems which might complicate assessment of the tolerability of the study medication.