A Study of KW-6356 in Patients With Parkinson's Disease on Treatment With Levodopa-containing Preparations

A Phase 2b Study of KW-6356 in Subjects With Parkinson's Disease on Treatment With Levodopa-containing Preparations

The primary objective of this study is to determine the recommended dose and evaluate the effect of KW-6356 on motor symptoms in Parkinson's disease and the primary endpoint is the change from baseline in Movement disorder society-unified Parkinson's disease rating scale(MDS-UPDRS) partIII score between KW-6356 and placebo in patients with Parkinson's disease on treatment with Levodopa-containing preparations as an adjunctive therapy.

Inclusion Criteria:

• Subject fulfills the UK Parkinson's Disease Society brain bank clinical diagnostic criteria.
• Parkinson's disease patients in Stages 2 to 4 on the Modified Hoehn and Yahr Scale. (mH&Y, Evaluation at ON state for patients who experience Wearing-off phenomenon)
• MDS-UPDRS partIII score of >= 15. (Evaluation at ON state)
• Subject who are responsive to levodopa/DCI (carbidopa or benserazide) combination therapy and who have been on the therapy for 6 months or longer without interruption at enrollment.
• Subject who have not started any new antiparkinsonian drugs and have been on a stable regimen of antiparkinsonian drugs in the 3 months before enrollment.

Exclusion Criteria:

• Use of any CYP3A4/5-related drugs within 2 weeks prior to enrollment.
• Use of any of the following drugs within 3 months (or 6 month in case of depot preparations) prior to enrollment; Antipsychotics, tiapride, metoclopramide, amoxapine, reserpine, tetrabenazine, methyldopa, papaverine, Levodopa/carbidopa intestinal gel and apomorphine hydrochloride injection
• Treatment by transcranial magnetic stimulation (TMS) within 6 months prior to enrollment.
• Neurosurgical operation for Parkinson's disease. (stereotactic surgery, deep brain stimulation or gamma knife)
• Subject who have received administration of adenosine A2A receptor antagonist.
• 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 subinvestigator including those who are unable to communicate or to cooperate with the investigator or subinvestigator.