A Study of E2020 in Patients With Dementia With Lewy Bodies (DLB), Followed by a Long-term Extension Phase

• Change from baseline in Mini Mental State Examination (MMSE) [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
• Change from baseline in Neuropsychiatric Inventory (NPI) [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]

• Co-primary parameters:Change from baseline in Mini Mental State Examination (MMSE) [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]
• Change from baseline in Neuropsychiatric Inventory (NPI) [ Time Frame: 12 weeks ] [ Designated as safety issue: No ]

The purpose of this study is to confirm the efficacy of E2020 in patients with dementia with Lewy bodies (DLB).

• Drug: E2020
  E2020 tablets will be orally administered once daily after breakfast for 52 weeks: 5 mg group: Weeks 1-2 E2020 3 mg, Weeks 3-24 E2020 5 mg, Weeks 25-52 E2020 10 mg.
• Drug: E2020
  E2020 tablets will be orally administered once daily after breakfast for 52 weeks: 10 mg group: Weeks 1-2 E2020 3 mg, Weeks 3-6 E2020 5 mg, Weeks 7-52 E2020 10 mg.
• Drug: Placebo
  Matching placebo tablets will be orally administered once daily after breakfast for 52 weeks: Placebo group: Weeks 1-16 placebo, Weeks 17-18 E2020 3 mg, Weeks 19-24 E2020 5 mg, Weeks 25-52 E2020 10 mg

• Experimental: 1
  Intervention: Drug: E2020
• Experimental: 2
  Intervention: Drug: E2020
• Placebo Comparator: 3
  Intervention: Drug: Placebo

Inclusion Criteria

1. Patients diagnosed as probable dementia with lewy bodies (DLB) according to the diagnostic criteria for DLB
2. Patients having caregivers throughout the study who submit written consent to cooperate with this study, can routinely stay with patients 3 days or more a week (at least 4 hours a day), provide patients' information necessary for this study, assist treatment compliance, and escort the patients on required visits to study institution
3. Clinical Dementia Rating (CDR) score is ≥ 0.5
4. Mini-Mental State Examination (MMSE) score is ≥ 10 and ≤ 26

Exclusion Criteria

1. Patients diagnosed with Parkinson's disease with dementia (PDD)
2. Patients who received anti-dementia drug therapy at the same institution
3. Patients who received anti-dementia drug therapy within 12 weeks before start of Screening
4. Patients with a complication of serious neuropsychiatric disease(s) such as stroke, brain tumor, schizophrenia, epilepsy, normal pressure hydrocephalus, mental retardation, brain trauma with unconsciousness, or a history of brain surgery causing unrecovered deficiency

5. Patients with severe extrapyramidal disorders (Hoehn & Hahr staging score is

   ≥ IV)

6. Patients whose systolic blood pressure is < 90 mmHg or pulse rate is < 50/bpm at screening