["parkinson's disease"]
['kw-6356', 'kw-6356', 'placebo']

        Inclusion Criteria:

          -  Subject fulfills the UK Parkinson's Disease Society brain bank clinical diagnostic
             criteria

          -  Parkinson's disease patients in Stages 1 to 3 on the Modified Hoehn and Yahr Scale

          -  MDS-UPDRS part III score of ≥ 15

        Exclusion Criteria:

          -  Use of any CYP3A4/5-related drugs within 2 weeks prior to enrollment.

          -  Use of any of the specified antiparkinsonian drugs and dopamine antagonists during the
             specified period.

          -  Treatment with levodopa/DCI at any time in the past for a period of 4 weeks or more.

          -  Neurosurgical operation for Parkinson's disease (stereotactic surgery, deep brain
             stimulation or gamma knife), or treatment by transcranial magnetic stimulation (TMS).

          -  Either of the following criteria consecutively at screening and enrollment;

               -  Resting Pulse > 100 bpm

               -  Resting systolic blood pressure > 140 mmHg, or diastolic blood pressure > 90 mmHg

          -  Significant dementia or a Mini-Mental State Examination (MMSE) score of ≤ 23.

          -  Subject has a history or evidence of suicidal ideation (severity of 4 or 5) or any
             suicidal behavior based on an assessment with the Columbia-Suicide Severity Rating
             Scale (C-SSRS) at baseline.

          -  Anyone otherwise considered unsuitable for the study by the investigator or
             sub-investigator including those who are unable to communicate or to cooperate with
             the investigator or sub-investigator.
      