Outcome is defined as change in total Unified Parkinson's Disease Rating Scale (UPDRS) between the baseline visit and month 12 or the time to require dopaminergic therapy (last visit before subject goes on dopaminergic therapy), whichever occurs first. The UPDRS score has 4 components. Part I assesses mentation; Part II assesses activities of daily living; Part III assesses motor abilities; Part IV assesses complications of therapy. A total of 44 items are included in Parts I-III. Each item will receive a score ranging from 0 to 4 where 0 represents the absence of impairment and 4 represents the highest degree of impairment. Part IV contains 11 items, 4 of these items are scored 0-4 in the same manner, and 7 are scored 0-1, with 0 indicating the absence of impairment and 1 indicating the presence of impairment. Total UPDRS score represents the sum of these items in Parts I-IV. A total of 199 points are possible. 199 represents the worst (total) disability), 0--no disability.

Participants are 99 subjects with early Parkinson disease not requiring dopaminergic therapy.

Tolerability will be judged by the proportion of subjects enrolled in a dosage group able to complete the 12 month study or to the time of initiation of dopaminergic therapy on their original assigned dosage. Tolerability of each active arm will be compared to placebo group.

The outcome is defined as change in Mental subscale of Unified Parkinson's Disease Rating Scale(UPDRS Part I) between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. UPDRS Part I: Mentation, behavior and mood, consisting of 4 questions answered on a 0-4 point scale where 0 represents the absence of impairment and 4 represents the highest degree of impairment. Total score represents the sum of these 4 questions. A greater increase in score indicates a greater increase in disability. A total of 16 points are possible. 16 represents the worst (total) disability), 0--no disability.

All participants were used in primary and secondary outcome analyses

The outcome is defined as change in ADL subscale of the Unified Parkinson's Disease Rating Scale(UPDRS Part II) between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. UPDRS Part II: Activities of Daily Living in the week prior to the designated visit, consisting of 13 questions answered on a 0-4 point scale where 0 represents the absence of impairment and 4 represents the highest degree of impairment. Total Part II score represents the sum of these 13 questions. A greater increase in score indicates a greater increase in disability. A total of 52 points are possible. 52 represents the worst (total) disability), 0--no disability

All participants were included in the primary and secondary outcome analyses

The outcome is defined as change in Motor subscale of the Unified Parkinson's Disease Rating Scale(UPDRS Part III) between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. UPDRS Part III: motor abilities at the time of the visit, consisting of 27 items (including 13 general questions and 14 sub-questions) each answered on a 0-4 point scale where 0 represents the absence of impairment and 4 represents the highest degree of impairment. Total Part III score represents the sum of these 27 items. A total of 108 points are possible. 108 represents the worst (total) disability), 0--no disability.

All participants were included in primary and secondary outcome analyses

The Modified Hoehn & Yahr Scale is an 8-level Parkinson's disease staging instrument. The outcome is defined as change in Modified Hoehn & Yahr Scale between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. A greater increase in stage indicates a greater increase in disability. Stage ranges from 0-5 (also including 1.5 and 2.5) with 0 indicating no disability and 5 indicating maximum disability.

All participants were included in primary and secondary outcome analyses

The Schwab & England scale is an investigator and subject assessment of the subject's level of independence at all scheduled study visits. The subject will be scored on a percentage scale reflective of his/her ability to perform acts of daily living in relation to what he/she did before Parkinson's disease appeared. The outcome is defined as change in Schwab & England Independence Scale between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. Higher decrease in score indicates higher disability. Score ranges from 100% (complete independence) to 0% (total disability).

All participants were included in primary and secondary outcome analyses

The Beck Depression Inventory (BDI) is a validated self-reported 21-item depression scale that was tested and validated as a reliable instrument for screening for depression in PD. The outcome is defined as change in BDI-II between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. Total BDI score represents the sum of these 21-items. A higher change in score indicates a greater increase in disability. Total score of 0-13 is considered minimal, 14-19 is mild, 20-28 is moderate, and 29-63 is severe.

All participants were included in primary and secondary outcome analyses

The Montreal Cognitive Assessment(MoCA) is a brief 30-point screening instrument that was developed and validated to identify subjects with mild cognitive impairment. The outcome is defined as change in MoCA between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. Total MoCA score represents the sum of these 30-points, with a lower score indicating greater cognitive impairment. 30 is the maximum score, with a score of 26 or higher considered normal and below 26 indicative of Mild Cognitive Impairment.

All participants were included in primary and secondary outcome analyses

The PD Quality of Life Scale(PDQ-39) asks the subject to evaluate how Parkinson disease has affected their health and overall quality of life at that point in time. The total quality of life scale includes subscales relating to social role, self-image/sexuality, sleep, outlook, physical function and urinary function. The outcome is defined as change in PDQ-39 between the baseline visit and month 12 or the time of sufficient disability to require dopaminergic therapy. It is scored on a scale of zero to 100, with lower scores indicating better health and higher scores more severe disability.

All participants were included in primary and secondary outcome analyses

General disorders and administration site conditions. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects.

Nervous system disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Infections and infestations. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Nervous System disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Gastrointestinal Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

General Disorders and Administration Site Conditions. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Gastrointestinal Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Infections and Infestations. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Psychiatric Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Nervous System Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Psychiatric Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Gastrointestinal Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Gastrointestinal Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Infections and Infestations. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Musculoskeletal and Connective Tissue Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.

Vascular Disorders. Common adverse experience/event is defined as AE occurs to 5(about 5%) or more subjects. They will also be tabulated by treatment groups.