• Men or women between the ages of 50 and 80 years, inclusive at the time of screening.

• Clinical diagnosis of Parkinson's disease as defined by the United Kingdom Parkinson's disease (PD) Society Brain Bank Clinical Diagnostic Criteria and Movement Disorder Society Parkinson's disease Criteria (must meet both criteria); must include bradykinesia and responsiveness to levodopa.

• Maintenance on stable Parkinson's disease therapy for at least 28 days prior to Screening/Visit 1 through treatment period to Day 42, with demonstratable medication efficacy as assessed by the Investigator.

• Severity of Parkinson's disease symptoms assessed by Hoehn and Yahr Staging score ≤3.0 (assessed in the ON state).

• Maintenance on permitted stable non-Parkinson's disease therapy for at least 28 days prior to Day 1 through the treatment period to Day 42.

• Female participants of childbearing potential must have a negative urine pregnancy test at Screening and baseline, as well as be non-lactating and must agree to use a highly effective method of contraception during the study and for 30 days following last dose of study drug.

• Male participants must be sterile or sexually inactive or agree not to father a child during the study and for 1 month after the last dose of study medication and must agree to use a barrier method for contraception. Female partners of male subjects must adopt a highly effective method of contraception

• Adequate visual, hearing, cognitive and physical ability and willingness to comply with study drug administration, scheduled visits, treatment plan, laboratory tests, and other study-related procedures to complete the study

• Institutional Review Board/Ethics Committee-approved consent form signed and dated by the participant