18-Month Study of the Efficacy of Xaliproden (SR57746A) in Patients With Mild-to-Moderate Dementia of the Alzheimer's Type

Inclusion Criteria: * Diagnosis of probable Alzheimer's disease using NINCDS-ADRDA criteria * Mild to moderate degree of severity of dementia as assessed by the Mini-Mental State Examination score of 16 to 26 (inclusive) * Potential participant may be treated with conventional Alzheimer's disease therapy and must be on stable dose for at least 6 months prior to the randomization and during the entire study period * Potential participant must have a reliable caregiver and must be living in a community or in an assisted living facility * Mother tongue is English, Spanish or French (oral and written fluency) * Signed informed consent from potential participant or legal representative and identified caregiver Exclusion Criteria: * Potential participant with any other cause of dementia. * Potential participant with serious health problems other than Alzheimer's disease * Use of an investigational drug within two months prior to randomization or during this study