Please assess the completion status of the following clinical trial:

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

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: DOUBLE
- Phase: PHASE2
- Number of Arms: None

Eligibility Criteria:
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.

- Gender: ALL
- Minimum Age: 30 Years
- Maximum Age: None
- Healthy Volunteers: f

Based on this trial design, predict the completion outcome and termination type (if applicable).