Patient description: The patient is a 55-year-old man who was recently diagnosed with Parkinson's disease. He is complaining of slowness of movement and tremors. His disease is ranked as mild, Hoehn-Yahr Stage I. His past medical history is significant for hypertension and hypercholesterolemia. He lives with his wife. They have three children. He used to be active with gardening before his diagnosis. He complains of shaking and slow movement. He had difficulty entering through a door, as he was frozen and needed guidance to step in. His handwriting is getting smaller. He is offered Levodopa and Trihexyphenidyl. He is an alert and cooperative man who does not have any signs of dementia. He does not smoke or use any illicit drugs.

Clinical trial eligibility criteria: eligible ages (years): 50.0-999.0,  Early Parkinson Disease Key 1. Diagnosed with "Clinically Probable PD" according to the MDS clinical diagnostic with documented onset of symptoms per treating physician's records within three years of the Screening visit. Disease severity according to modified Hoehn & Yahr stage ≤ 2; 2. Projected to not require to start dopaminergic therapy within 9 months from Baseline; 3. Female subjects must be not of childbearing potential, e.g., documented evidence that they are surgically sterile (e.g., hysterectomy, partial hysterectomy, bilateral oophorectomy, bilateral tubal ligation), or post-menopausal (at least 12 months since last menses) prior to Screening with serum Follicular Stimulating Hormone (FSH) ≥40 mIU/mL). Key  Current, or within 60 days of Screening, use of any prescription, investigational, or over the counter medication for the symptomatic treatment of PD or to slow the progression of PD. Treatment with Monoamine Oxidase B (MAOB) inhibitors will be allowed if the dose is stable for at least 30 days prior to Screening and subjects agree to remain on it for the duration of the study; 2. Prior use of dopaminergic therapy (e.g., levodopa, dopamine agonist, amantadine) for 30 or more days any time in the past; 3. A diagnosis of a significant central or nervous system disease affecting the subject's cognition or motor function at any time, such as another neurodegenerative disorder, multiple sclerosis or stroke. This does not transient neurological deficits such as transient ischemic attacks or migraine aura; 4. A diagnosis of a medical condition that could interfere with interpretation of the MDS-UPDRS during the trial (e.g., musculoskeletal disorders); 5. Most recent DaT SPECT scan not compatible with PD (i.e., Scans Without Evidence of Dopaminergic Deficit [SWEDD]) based on central read by a study physician; 6. MRI scan of the brain performed after onset of PD suggestive of secondary Parkinsonism (e.g., subdural hematoma, normal pressure hydrocephalus, or infarcts of the basal ganglia); 7. Any clinically significant cardiac abnormality in the opinion of the investigator. This would myocardial infarction in the six months prior to screening, or significant ECG abnormality, including heart-rate corrected interval QT (QTc) based on Fridericia's correction formula > 470 milliseconds; 8. Subject report of recent (6-month) illicit drug use (other than marijuana), or excessive intake of alcohol (as per investigator opinion); 9. Subject report of marijuana use within one month of Screening or subject not willing to forgo marijuana use through the trial; 10. Participation in other investigational drug trials within 30 days prior to Screening; 11. Any concomitant medication or medication excluded that could put subject at risk, or interfere with study evaluations (Section 7.4); 12. Recent use of medications that can cause Parkinsonism and suspicion of the investigator that it could have worsened the subject's Parkinsonism. This includes neuroleptics (e.g., olanzapine, risperidone, haloperidol), some anti-nausea medications (e.g., prochlorperizine, metoclopramide) and others (e.g., flunarizine, methyldopa); 13. Use of medications that affect the dopamine system though do not cause or treat PD, within 60 days of Screening. This includes stimulants (e.g., methylphenidate, amphetamine derivatives, modafinil) and Monoamine Oxidase A (MAOA) inhibitors (e.g., phenelzine, and tranylcypromine). Note that antidepressants are acceptable as long as the subject has remained on them at a stable dose for over 60 days prior to Screening and plans to remain on them through the study; 14. Any malignant disease other than basal cell carcinoma of the skin with evidence of disease within the past 5 years, or with the potential for recurrence