Please assess the completion status of the following clinical trial:

Trial Title: D-serine Adjuvant Treatment for Parkinson's Disease

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: CROSSOVER
- Observational Model: None
- Primary Purpose: None
- Time Perspective: None
- Masking: TRIPLE
- Phase: PHASE4
- Number of Arms: 2.0

Eligibility Criteria:
Inclusion Criteria:~* PD diagnosis~* ≥2 on UPDRS items 32,33~* receive treatment with L-dopa alone or in combination with other antiparkinsonian medications.~Exclusion Criteria:~* current or previous history of other neurological disorders~* unstable medical conditions~* renal pathology~* pregnant female patients excluded

- Gender: ALL
- Minimum Age: 30 Years
- Maximum Age: 75 Years
- Healthy Volunteers: f

Study Arms:
- 1 (Type: PLACEBO_COMPARATOR): None
- 2 (Type: EXPERIMENTAL): None

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