Please assess the completion status of the following clinical trial:

Trial Title: Study of Combination Therapy With Dimebon and Donepezil (Aricept) in Patients With Alzheimer's Disease

Study Design Characteristics:
- Allocation: None
- Intervention Model: SINGLE_GROUP
- Observational Model: None
- Primary Purpose: TREATMENT
- Time Perspective: None
- Masking: NONE
- Phase: PHASE2
- Number of Arms: 1.0

Eligibility Criteria:
Inclusion Criteria:~* Alzheimer's disease~* On donepezil (Aricept)~* Caregiver who cares for the patient at least 5 days per week~Exclusion Criteria:~* Unstable medical illnesses or significant hepatic or renal disease~* Other primary psychiatric or neurological disorders

- Gender: ALL
- Minimum Age: 50 Years
- Maximum Age: None
- Healthy Volunteers: f

Study Arms:
- Dimebon (Type: EXPERIMENTAL): 20 mg by mouth 3 times a day

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