A Study of Trontinemab in Participants With Early Symptomatic Alzheimer's Disease

Inclusion Criteria:

• Willingness and ability to complete all aspects of the study (including MRI,clinical genotyping, and PET imaging or CSF as applicable) for the duration of thestudy. The participant should be capable of completing assessments either alone orwith the help of the study partner

• Adequate visual and auditory acuity, in the investigator's judgment, sufficient toperform the neuropsychological testing (eyewear and hearing aids are permitted)

• Evidence of AD pathological process, as confirmed on amyloid PET scan. A CSFtau181/Aβ42 ratio may be used as an alternative option if amyloid PET is notavailable

• Probable AD dementia or MCI due to AD, also known as an Alzheimer's clinicalsyndrome clinical Stage 3 or Stage 4

• Screening MMSE score ≥ 22 and CDR-GS of 0.5 or 1.0

• Participant- and/or Informant-reported history of cognitive decline with gradualonset and progression over the last 1 year before screening

• A Repeatable Battery for the Assessment of Neuropsychological Status Delayed MemoryIndex (RBANS DMI) score of 85 or order

• Availability of a "study partner" as defined by the protocol

Exclusion Criteria:

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

• History or presence of clinically significant cerebrovascular disease

• History of severe, clinically significant (persistent neurologic deficit orstructural brain damage) central nervous system (CNS) trauma

• History or presence of clinically significant intracranial mass

• MRI evidence of significant cerebral abnormalities or inability to tolerate MRIprocedures or contraindication to MRI

• Any other medical conditions (e.g., cardiovascular, hepatic, renal disease) whichare not stable and adequately controlled or which in the opinion of the investigatorcould affect the participant's safety in the study or interfere with the studyassessments

• History of malignancy with the following exceptions: if considered to be cured;malignancies with a negligible risk of metastasis or death