The purpose of this study is to evaluate the efficacy and safety of PF 04494700 in participants with mild to moderate Alzheimer's disease.

Inclusion Criteria:

• Mini Mental State Exam (MMSE) score between 14-26 (inclusive) at screening.
• Participants must be receiving acetylcholinesterase inhibitors on a stable dose for at least 4 months prior to randomization

Exclusion Criteria:

• Current evidence or history of neurological, psychiatric and any other illness that could contribute to non-Alzheimer's dementia.
• Known history of familial AD or any evidence for early onset AD known or possibly associated with genetic mutations.
• Evidence or history of diabetes mellitus Type 1 or Type 2.
• History or symptoms of autoimmune disorders.