Please assess the completion status of the following clinical trial:

Trial Title: Metformin Add-on Regimen Comparison Study in Japanese Participants With Type 2 Diabetes Mellitus (MK-0431A-136)

Study Design Characteristics:
- Allocation: RANDOMIZED
- Intervention Model: PARALLEL
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: DOUBLE
- Phase: PHASE3
- Number of Arms: 3.0

Eligibility Criteria:
Inclusion Criteria:~* Type 2 Diabetes Mellitus (T2DM)~* Currently being treated with diet/exercise and on stable dose of sitagliptin for ≥ 4 weeks, on any additional oral hypoglycemic agent (AHA) in the prior 8 weeks, and HbA1c ≥ 6.0% and ≤ 9.0%; or~* Currently being treated with diet/exercise and on stable dose of sitagliptin for ≥ 10 weeks, not on any additional oral AHA in the prior 8 weeks, and HbA1c ≥ 6.5% and \< 10.0%~Exclusion Criteria:~* Type 1 diabetes mellitus,~* Secondary diabetes mellitus, or~* Gestational diabetes mellitus

- Gender: ALL
- Minimum Age: 20 Years
- Maximum Age: 74 Years
- Healthy Volunteers: f

Study Arms:
- Metformin 500 mg q.d. (Type: EXPERIMENTAL): Participants will receive sitagliptin daily (continuing their pre-study dose), 2 metformin 250 mg tablets in the morning and 1 matching placebo tablet in the evening.
- Metformin 250 mg b.i.d. (Type: EXPERIMENTAL): Participants will receive sitagliptin daily (continuing their pre-study dose), 1 metformin 250 mg tablet and 1 matching placebo tablet in the morning and 1 metformin 250 mg tablet in the evening.
- Placebo (Type: PLACEBO_COMPARATOR): Participants will receive sitagliptin daily (continuing their pre-study dose), 2 matching placebo tablets in the morning and 1 matching placebo tablet in the evening.

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