The Effectiveness And Safety Of Donepezil Hydrochloride (E2020) In Subjects With Mild To Severe Alzheimer's Disease Residing In An Assisted Living Facility

Inclusion Criteria:

1. Age range: Subjects > 50 years of age.

2. Sex distribution: both men and women. Women must be two (2) years post-menopausal or
surgically sterile. Women of child bearing potential (< 1 year post menopausal) must
be practicing effective contraception and have a negative ß-hCG at screening (Women
who are breast feeding are excluded).

3. MMSE scores between 5 and 24 (inclusive).

4. Subjects must have diagnostic evidence of possible or probable AD either prior to or
at the screening visit based on Diagnostic and Statistical Manual of Mental
Disorders-IV (DSM-IV) and National Institute of Neurological and Communicative
Disorders and Stroke criteria.

5. CT or MRI within the last 12 months consistent with a diagnosis of AD without any
other clinically significant comorbid pathologies found. A copy of the report will be
required and will be collected. If there has been a significant change in clinical
status suggestive of stroke or other neurological disease in addition to AD with onset
between the time of the last CT or MRI and the screening evaluation, the scan should
be repeated during screening.

6. The caregiver/ informant can be a family member or a professional and must have had
contact with the subject at least 6 Weeks prior to study entry and spent at minimum 3
days a Week (10 hours per Week) with the subject. For study visit, the subject can be
seen at the Assisted Living Facility (ALF) or in the clinic setting of the
Investigator. At each visit, the caregiver/informant will provide the information for
completion of the safety and efficacy assessments based on knowledge of and time spent
with the subject.

7. Subjects must reside in an ALF.

8. The subject is expected to complete all procedures scheduled during the screening,
baseline, interim, and final visits including all efficacy assessments.

9. Putative non-prescription/prescription cognitive enhancers (e.g. ginkgo, high-dose
vitamin E, lecithin, estrogen, non-steroidal anti-inflammatory drugs [NSAIDs]) will
not be excluded but will be discouraged. If a putative cognitive enhancer is present,
the dosage must have been stable for at least 3 months prior to the screening visit
and should not change during the course of the study.

10. Subjects with controlled hypertension (sitting diastolic BP < 95 mmHg), right bundle
branch block (complete or partial), and pacemakers may be included in the study.

11. Subjects with thyroid disease also may be included in the study provided they are
euthyroid and stable on treatment for at least 3 months prior to screening.

12. Subjects with a history of seizure disorder are allowed provided that they are on
stable treatment for at least 3 months prior to screening and have not had a seizure
within the past 6 months.

13. Subjects must be able to swallow tablet medication -- no crushing of tablet is
allowed.

14. Health: independent or ambulatory aided (i.e., walker or cane, to wheelchair); vision
and hearing (eyeglasses and/or hearing aid permissible) sufficient for compliance with
testing procedures.

15. Subjects must be sufficiently proficient in the language in which the assessments are
to be conducted.

16. Subjects must have clinical laboratory values within normal limits, and within the
Eisai (sponsor) guidelines, or abnormalities considered not clinically significant by
the investigator and sponsor.

Exclusion Criteria:

1. Age range: Subjects < 50 years of age.

2. MMSE score of ≤4 or ≥25.

3. Subjects with active or clinically significant conditions affecting absorption,
distribution or metabolism of the study medication (e.g., inflammatory bowel disease,
gastric or duodenal ulcers or severe lactose intolerance).

4. Subjects with a known hypersensitivity to piperidine derivatives or cholinesterase
inhibitors.

5. Subjects living in a skilled nursing home or subjects living in an ALF who may be
moved to a skilled nursing home during the course of the study. Subjects who transfer
from an ALF to a skilled nursing home during this study will be discontinued.

6. Subjects who have taken the following medications within the last 3 months prior to
screening will be not eligible: Aricept, Exelon, Cognex, Razadyne, Metrifonate,
Namenda or propentofylline.

7. Subjects without a reliable caregiver/informant or subjects whose caregiver is
unwilling or unable to complete the outcome measures and fulfill the requirements of
this study.

8. Subjects with clinically significant obstructive pulmonary disease or asthma,
untreated for > 3 months.

9. Subjects with recent (< 2 years) hematologic/ oncologic disorders, not including mild
anemia or basal or squamous cell carcinoma of the skin. Subjects with current evidence
of malignant neoplasm or recurrent or metastatic disease will be excluded.

10. Evidence of clinically significant, active gastrointestinal, renal, hepatic, endocrine
or cardiovascular system disease.

11. Subject with a current DSM-lV diagnosis of Major Depressive Disorder (MDD) or any
current primary psychiatric diagnosis other than Alzheimer's disease (as per DSM-lV).

12. Subjects with dementia complicated by other organic disease (DSM 290.30 or 290.11) are
excluded; depression or delusions are common in Alzheimer's disease, and subjects with
severe symptoms so pronounced that they warrant an alternative, concurrent diagnosis,
are excluded.

13. Subjects with a known or suspected history of alcoholism or drug abuse (within the
past 10 years).

14. Subjects with treated hypothyroidism that have not been on a stable dose of medication
for 3 months prior to screening and who do not have normal serum Free T3, Free T4 and
TSH at screening.

15. Subjects with treated vitamin B-12 deficiency who have not been on a stable dose of
medication for at least 3 months prior to the study screening visit and who do not
have normal serum B-12 levels at screening.

16. Any subject taking a prohibited medication will be excluded.

17. Any condition which would make the subject or the caregiver, in the opinion of the
investigator, unsuitable for the study.