Efficacy and Safety Study of Gantenerumab in Participants With Early Alzheimer's Disease (AD)

Key Inclusion criteria:

- Meets National Institute on Aging/Alzheimer's Association (NIAAA) core clinical
criteria for probable AD dementia or prodromal AD (consistent with the NIAAA
diagnostic criteria and guidelines for mild cognitive impairment)

- Evidence of the AD pathological process, as confirmed by CSF or amyloid PET scan

- Demonstrated abnormal memory function

- MMSE score greater than or equal to 22 (≥ 22)

- Clinical dementia rating-global score (CDR-GS) of 0.5 or 1.0

- Availability of a reliable study partner who accepts to participate in study
procedures throughout the 2 years duration of study

- If receiving symptomatic AD medications, the dosing regimen must have been stable for
3 months prior to baseline and until randomization.

- For enrollment in the China extension, patients must have residence in mainland China,
Hong Kong, or Taiwan and be of Chinese ancestry.

Key Exclusion criteria:

- Any evidence of a condition other than AD that may affect cognition

- History of schizophrenia, schizoaffective disorder, major depression, or bipolar
disorder

- History or presence of clinically evident systemic vascular disease that in the
opinion of the investigator has the potential to affect cognitive function

- History or presence of clinically evident cerebrovascular disease

- At risk for suicide in the opinion of the investigator

- Patients with evidence of folic acid deficiency

- Alcohol and/or substance abuse or dependants in past 2 years

- Relevant brain hemorrhage, bleeding disorder and cerebrovascular abnormalities

- Any contraindications to brain MRI

- Unstable or clinically significant cardiovascular, kidney or liver disease

- Uncontrolled hypertension