A Study of Istradefylline (KW-6002) for the Treatment of Parkinson's Disease in Patients Taking Levodopa

A 12-week, Double Blind, Placebo-controlled, Randomized, Parallel Group, Multicenter, Fixed Dose Study to Evaluate the Efficacy and Safety of a 20 mg/d Oral Dose of KW-6002 (Istradefylline) as Treatment for Parkinson's Disease in Patients With Motor Response Complications on Levodopa/Carbidopa Therapy.

Status

Completed

Phases

Phase 3

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00199407

Enrollment

230

Registered

2005-09-20

Start date

2004-06-30

Completion date

2006-01-31

Last updated

2024-04-25

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Parkinson's Disease

Keywords

Parkinson's disease, levodopa, end of dose wearing off, OFF time

Brief summary

To establish the efficacy of a 20 mg/day dose of istradefylline for reducing the percentage of OFF time in patients with advanced Parkinson's disease (PD) treated with levodopa.

Detailed description

To establish the efficacy of a 20 mg/d dose of istradefylline for reducing the percentage of OFF time in patients with advanced Parkinson's disease (PD) treated with levodopa. Patients who meet entry criteria will be randomized in a 1 to 1 ratio to either istradefylline or matching placebo. Patients will be treated for 12 weeks and will have interim visits and end of treatment visit to assess the efficacy and safety of istradefylline as compared to placebo.

Interventions

DRUGIstradefylline (KW-6002)

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Masking

DOUBLE

Eligibility

Sex/Gender

ALL

Age

30 Years to No maximum

Healthy volunteers

Inclusion criteria

1. UK Parkinson's Disease Society (UKPDS) brain bank criteria (Step 1 and 2) for PD. 2. PD stages 2-4 in the OFF state for Modified Hoehn and Yahr Scale. 3. On levodopa/carbidopa for at least one year, stable dose in past 4 weeks. 4. Currently take at least three doses of levodopa/carbidopa per day. 5. Predictable end of dose wearing off. 6. Able to satisfactorily complete Hauser version of a Parkinson's diary. 7. Have an average of 180 minutes of OFF time on two 24 hour diaries. 8. Be at least 30 years of age.

Exclusion criteria

1. Neurosurgical treatment for PD. 2. History of psychosis. 3. Diagnosis of atypical parkinsonism, secondary parkinsonism variant or Parkinson's plus syndromes. 4. Diagnosis of cancer within 5 years. 5. Mini-mental status examination score of 25 or less. 6. History of seizures or neurologic malignant\_syndrome. 7. Clinical depression.

Design outcomes

Primary

Measure	Time frame
To establish the efficacy of a 20 mg/d dose of istradefylline for reducing the percentage of OFF time in patients with advanced Parkinson's disease (PD) treated with levodopa/carbidopa.	—

Secondary

Measure	Time frame
To evaluate the change in percentage of ON time (without dyskinesia, with dyskinesia, with non-troublesome dyskinesia, and with troublesome dyskinesia).	—
To evaluate the change in Unified Parkinson's Disease Rating Scale (UPDRS) Motor Examination score (part III) and/or in Activities of Daily Living (ADL) score (part II).	—
To evaluate the change in Parkinson's Disease Questionnaire (PDQ-39) and Medical Outcomes Study 36-item Short Form (SF-36).	—
To evaluate the efficacy of a 20 mg/d dose of istradefylline for reducing the total hours of OFF time.	—
To evaluate change in the Clinical Global Impression - Severity of Illness scale (CGI-S).	—
To evaluate the safety of a 20 mg/d dose of istradefylline.	—
To evaluate the change in the Patient Global Impression - Improvement scale (PGI-I).	—

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026