Safety and Efficacy Study of SYN115 in Parkinson's Patients Using Levodopa to Treat End of Dose Wearing Off

A Double-blind, Randomized, Placebo-controlled Study of the Safety and Efficacy of SYN115 as Adjunctive Therapy in Levodopa-treated Parkinson's Subjects With End of Dose Wearing Off

The purpose of this research study is to test the effect of SYN115 compared to placebo (a "sugar pill" that looks like SYN115 but does not include active drug) on movement during the "on" and "off" states as well as other symptoms that some patients with Parkinson's disease experience. This study will also look at whether or not patients with Parkinson's disease experience "side-effects" with SYN115.

Inclusion Criteria:

• Meet Parkinson's Disease (PD) diagnosis consistent with UK PD diagnostic criteria
• Meet Hoehn and Yahr PD stage
• Good response to levodopa
• Stable regimen of anti-parkinson medications
• Are able to complete a Parkinson's disease diary
• If of childbearing potential(male and female), use an acceptable method of birth control
• Able and willing to sign an IRB/IEC approved informed consent
• Able and willing to understand study requirements, follow study instructions, attend all visits and undergo all planned tests.

Exclusion Criteria:

• Secondary or atypical Parkinson's
• Neurosurgical intervention for Parkinson's disease
• Treatment with apomorphine
• Treatment with anti-psychotic drugs
• Other abnormal findings on physical or neuro exam or history that in the opinion of the investigator would make subject unsuitable for the study or prejudice safety and efficacy evaluation
• MMSE less than 26
• Subjects with untreated or uncontrolled current episode of major depression
• Receipt of any anti-psychotic drugs greater than 1 month in the past 5 years or any exposure in past year (except for quetiapine at doses <100mg per day)
• Women pregnant or lactating
• History of hepatitis, cholangitis
• Untreated or uncontrolled hypothyroidism or hyperthyroidism
• Drops in blood pressure requiring medication to maintain blood pressure
• Any clinically significant out of range laboratory evaluations
• Known sensitivity to the study medication or its components
• Suicide ideation or type 4 or type 5 on the Columbia suicide severity rating scale
• Finding of malignant melanoma on full body skin exam
• Impulse disorder conditions