Patient description: A 57-year old farmer was diagnosed with Parkinson's disease a year ago. He experiences slowness of movement and tremors. 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 planting and taking care of their farm animals before his diagnosis. The patient 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 on Levodopa and Trihexyphenidyl. He stated his medications help with shaking and slow movement. But he still has difficulty initiating movements, stiffness and slowness in general. He is an alert and cooperative man who doesn't have any signs of dementia. He doesn't smoke or use any illicit drugs.

Clinical trial eligibility criteria: eligible ages (years): 0.0-999.0,  Parkinson's Disease Males and females between the ages of 30-80. Carry the diagnosis of idiopathic Parkinson's disease based on the presence of a characteristic clinical history and neurologic findings. Patients with relatively advanced disease (Hohen and Yahr stage II-IV in the off state). Patients with Parkinson's disease who have been treated with levodopa for at least one year. Patients with Parkinson's disease who require levodopa/carbidopa dosing at qid or more frequent intervals. Will have been receiving a stable regimen of treatment for Parkinson's disease for at least 4 weeks prior to study admission. Patients with Parkinson's disease who have associated motor response complications, including wearing-off fluctuations and peak-dose dyskinesias. Must be able to provide written informed consent. Patients with non-idiopathic parkinsonism or parkinsonian variants (e.g. juvenile Parkinson's disease; atypical parkinsonism; secondary parkinsonism; progressive supra-nuclear palsy; Shy-Drager syndrome; olivopontocerebellar atrophy will be excluded. Patients with a clinically significant illness of any organ system, including hepatic, renal, pancreatic, cardiovascular, endrocrinologic, gastrointestinal, respiratory, and neurologic system (except for those with Parkinson's disease) who may require a change in the treatment of that illness during the trial, or that may compromise the safety of the patient volunteer during the trial, or that may affect the ability of the volunteer to complete the trial will be excluded. No presence or history of any medical condition that can reasonably be expected to subject the patient to unwarranted risk, including cancer (except basal cell carcinoma or surgically excised carcinoma in situ of the cervix) as well as liver or pancreatic enzyme test results above the upper limit of normal. Patients who have had bilateral intracranial neurosurgical procedures such as nuclear ablation, stimulator implantation or tissue transplantation will be excluded. Patients with a history of seizures, including one or more infantile febrile seizures, or with a history of neuroepileptic malignant syndrome will be excluded. Patients who, for any reason, are judged by the investigator to be inappropriate for the study (including volunteers who are unable to communicate or to cooperate with the investigator) will be excluded. Patients with significant dementia (MMSE 25 or less), major psychotic illness, history of drug or alcohol abuse within past two years, and those who require drug therapy for a DSM-IV major depressive episode will be excluded. Patients who satisfy DSM-IV for alcohol or other drug abuse or dependence within two years of being exposed to KW-6002 will be excluded. Patients who have been treated with a centrally acting dopamine antagonist drug, including neuroleptic agents, metoclopramide and buspirone within three months (within six months for depot formulations) because of the potential liability for extrapyramidal side effects will be excluded. Patients taking nonselective monoamine oxidase inhibitors (phenelzine, isocarboxazid, tranylcypromine) will be excluded. Patients who have taken terfenadine, astemizole, cisapride, simvastatin, lovastatin, felodipine, or nifedipine within seven days before being exposed to KW-6002 will be excluded. Patients who have previously been exposed to KW-6002 or who have been treated with any other investigational agents within 12 weeks (or within five half-lives for investigational agents with a half-life of longer than 2 weeks) of being exposed to KW-6002 will be excluded. Patients with unacceptable prior/concomitant medications as will patients who have taken an investigational drug within the 2 months prior to randomization will be excluded. Pregnant will be excluded. Females who are of childbearing potential must be using a reliable method of contraception at the time they agree to study participation and must agree to continue using a reliable method of contraception hormonal products (e.g. approved oral contraceptives or long-term injectable or implantable contraceptives), double barrier methods (e.g. condom plus diaphragm; condom plus spermicidal foam; condom plus spermicidal sponge). an intra-uterine device or tubal ligation. All female volunteers of child-bearing potential must have a negative urine pregnancy test on the day before first exposure to KW-6002. No patients taking any medications listed in Section 6.2, Forbidden Medications