Study Evaluating TheSafety And Efficacy Of PF-05212377 Or Placebo In Subjects With Alzheimer's Disease With Existing Neuropsychiatric Symptoms On Donepezil

Inclusion Criteria:

- Clinical diagnosis of probable AD with supportive brain imaging documentation

- Have existing neuropsychiatric symptoms as defined by a score equal or greater than
10 on the NPI at screening, arising from item scores equal or greater than 2
(frequency X severity) on at least 2 domains.

- Has been on donepezil (stable dose of 5 mg or 10 mg) for at least four months, with
no intent to change such for the duration of the study.

Exclusion Criteria:

- Demonstrate extreme agitation, physical aggression or violence to themselves, their
caregiver, or others, and/or an inability to complete the ADAS-cog assessment at
Screening.

- Have major structural brain disease other than Alzheimer's Disease

- Other severe acute or chronical medical or psychiatric condition or laboratory
abnormality