12-Week, Double-Blind, Placebo-Controlled Study of 20 and 60 mg/Day Istradefylline in Parkinson's Disease Patients on Levodopa/Carbodopa

A 12-Week, Double-Blind, Placebo-Controlled, Randomized, Multicenter Study of the Efficacy of Doses of 20 and 60 mg/Day Istradefylline as Treatment for Parkinson's Disease in Patients With Motor Response Complications on Levodopa/Carbidopa

Status

Completed

Phases

Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00456794

Enrollment

325

Registered

2007-04-05

Start date

2002-03-31

Completion date

2003-10-31

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

A 12-week, multicenter, double-blind, randomized study designed to evaluate the safety and efficacy of 20 and 60 mg/day istradefylline compared with placebo in subjects with OFF-time phenomena and advanced Parkinson's disease treated with levodopa/carbidopa.

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. United Kingdom Parkinson's Disease Society brain bank diagnostic criteria (Steps 1 and 2). 2. Modified Hoehn and Yahr in the OFF state of II-IV. 3. Treated with levodopa/carbidopa for at least one year with a stable regimen for 4 weeks prior to randomization. 4. Taking at least 4 doses of levodopa/carbidopa per day (3 doses if at least 2 doses contained slow-release formulation) with predictable end of dose wearing off. 5. Successfully competed Parkinson's disease patient diary training with at least 120 minutes of OFF time per day. 6. Stable regimen of other antiparkinson's medications for 4 weeks prior to randomization. 7. At least 30 years of age and able to give written informed consent.

Exclusion criteria

1. Treatment with liquid levodopa/carbidopa within 4 weeks of randomization. 2. Treatment with MAO inhibitors except selegiline. 3. Treatment within 3 months with centrally acting dopamine antagonists (6 months for depot formulations), e.g., antipsychotic neuroleptics, metoclopramide, buspirone, amoxapine. 4. Neurosurgical operation for Parkinson's disease. 5. Atypical parkinsonism or secondary parkinsonism variants. 6. Diagnosis of cancer or evidence of continued disease within 5 years. 7. Clinically significant illness of any organ system (e.g., ALT or AST \> 1.5 times the upper limit of normal). 8. Mini-Mental Status Examination score of 25 or less. 9. History of drug or alcohol abuse or dependence within 2 years. 10. History of psychotic illness or seizures. 11. Clinically relevant depression disorder. 12. History of neuroleptic malignant syndrome. 13. Pregnancy or lactation. Women of child bearing potential must use a reliable method of contraception.

Design outcomes

Primary

Measure	Time frame
Change from Baseline to Endpoint in percentage of awake time per day in an OFF state based on the subjects' valid ON/OFF Parkinson's disease diary data.	—

Secondary

Measure	Time frame
Actual values and mean change from Baseline in percentage and total hours of awake time per day in the OFF state and ON state, UPDRS I-IV, II and III Scores during ON and OFF states, Global Clinical Impression-Improvement (CGI-I), safety	—

Countries

United States

Outcome results

None listed

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