The purpose of this study is to evaluate the safety and efficacy of five fixed dosage levels of FK962 or placebo for 24 weeks in subjects with mild to moderate Alzheimer's disease. Patient visits are every six weeks with limited efficacy measurements at week 6 and 18.

Inclusion Criteria:

• Subject satisfies the criteria for the clinical diagnosis of probable AD
• Subject has a score =< 4 on the Modified Hachinski Ischemia Scale at the screening visit

Exclusion Criteria:

• Subject has history or evidence of significant neurologic disease other than AD
• Subject has a history of stroke
• Subject has been treated for schizophrenia or recurrent mood disorder within the previous three years
• Subject has a hematologic or solid malignancy diagnosed within five years prior to study entry
• Subject has medically unstable COPD or asthma
• Subject has end stage CHF (NYHA Class III or IV) or unstable angina
• Subject has evidence of significant renal insufficiency
• Subject has insulin-dependent diabetes mellitus or HbA1C>8.5% at screening