MAyflOwer RoAD Study: A Study of RO4602522 in Patients With Moderate Severity Alzheimer Disease on Background Alzheimer Disease Therapy

Inclusion Criteria:

- Adult patients, 50-90 years of age inclusive at time of screening

- Probable Alzheimer disease, based on the National Institute of Neurological and
Communicative Disorders and Stroke (NINCDS)/Alzheimer's Disease and Related Disorders
Association (ADRDA) and DSM-IV-TR criteria

- MMSE score at screening between 13 and 20, inclusive

- Body mass index (BMI) between 18 and 36 kg/m2 (inclusive) at screening

- Modified Hachinski Ischemia Score of
- Patients with Cornell Scale for Depression in Dementia (CSDD) scores screening

- Receiving treatment with donepezil or rivastigmine, galantamine or any of these
AChEIs in combination with memantine for at least 4 months before screening, with
their dose and formulation stabilized at least 3 months before screening. All
formulation and dosages are allowed except donezepil 23 mg (alone or in combination)

- Females of childbearing potential must have a negative pregnancy test and must agree
to use effective contraception

- Generally healthy and ambulatory or ambulatory-aided (i.e., walker or cane)

- Have a reliable caregiver or some other identified responsible person who has
frequent contact with the patient

Exclusion Criteria:

- Any neurological or psychiatric condition that may currently or during the course of
the study impair cognition or functioning that is not associated with Alzheimer's
disease

- Background of mental retardation

- Uncontrolled behavioral symptoms incompatible with compliance or evaluability

- Alcohol and/or substance abuse or dependence (DSM-IV-TR) in the past 2 years, except
nicotine use which is allowed. However, smokers treated with nicotine replacement
therapy or bupropion are excluded

- Unstable or poorly controlled hypertension as assessed by the investigator

- Unstable or clinically significant cardiovascular disease that could be expected to
progress, recur, or change during study period to such an extent that it could bias
the assessment of the clinical or mental status of the patient

- Inadequate hepatic, renal or thyroid function

- Positive for hepatitis B, hepatitis C or HIV infection

- Poorly controlled diabetes

- Requiring nursing home care. Patients living in assisted living facilities are
allowed if a reliable caregiver is available (see inclusion criteria)

- Current treatment for AD other than those listed in inclusion criteria

- Participation at any time in an active AD vaccine study

- Participation in a passive AD immunization study less than 1 year before screening,
with exceptions as per protocol

- Psychotropic medication as defined by protocol