• Male or female between 40 years of age and older

• Body mass index of 19.0-40.0 kg/m2;

• Diagnosis of PD that is consistent with the UK Parkinson's Disease Society (UKPDS) Brain Bank diagnostic criteria;

• Hoehn and Yahr Scale stage classification of 2 or 3 when in the ON state;

• Have a clinically meaningful response to levodopa (levodopa + DDCI combination) based on Investigator assessment, and meet the following:

‣ Have been on a stable and optimal dose of levodopa (levodopa + DDCI combination: minimum dose of levodopa equivalent to 100 mg three times daily) for at least 4 weeks prior to Screening, and are expected to continue the same dose regimen throughout the Double-blind Treatment Period;

⁃ If taking other anti-parkinsonian medications (MAO-B \[monoamine oxidase B\] inhibitor, COMT \[catechol-O-methyltransferase\] inhibitor, dopamine agonist) in addition to levodopa, have been on a stable dose for at least 4 weeks prior to Screening and are expected to continue the same dose regimen throughout the Double-blind Treatment Period;

∙ 7\. Have wearing-off symptoms and levodopa-induced dyskinesia as per Investigator judgment; 8. Properly complete and return a self-reported home diary for motor function status (Hauser Diary) during the Screening Period, which confirms 3 days (ie, 3 consecutive, 24-hour periods) immediately prior to Baseline, each with at least 2½ hours of OFF time during waking hours.

∙ 9\. Has a caregiver to assist with study participation, if determined by the Investigator to be necessary.