Alzheimer's Plasma Extension

Inclusion criteria

• Documentation of the participant's informed consent to study procedures and for the use of protected health information (HIPAA Authorization, if applicable). Informed consent processes and documentation must adhere to state laws/local requirements, including consent provided by the participant's legally authorized representative (LAR), responsible next of kin, surrogate consent with assent, etc.
• Previously consented to participate in A3-45 screening.
• Has A3-45 screening plasma biomarker results required for determining eligibility to participate in the A3-45 trial.
• If an amyloid PET scan was conducted in A3-45, the scan was determined to be below the 20 centiloid cutpoint required for eligibility into the treatment arms of the A3 or A45 trial.
• As assessed by the site PI, participant is likely to be able to comply with the protocol, including completion of all required procedures for the duration of the study, and has adequate vision, hearing (hearing aid permitted), and literacy in English or Spanish sufficient for compliance with required testing procedures.

Exclusion criteria

• Current treatment with an FDA approved medication for Alzheimer's disease, including prior or current treatment with a prohibited medication.
• Enrollment in another investigational study, or intake of investigational drug, within 30 days prior to screening, or five half-lives of the investigational drug, whichever is longer, unless it can be documented that the participant was in the placebo treatment arm.

Participants enrolled in other observational studies may be permitted with Medical Monitor review and approval.

• Screen failed from A3-45 due to not meeting basic inclusion criterion (i.e., age requirement; current diagnosis of AD dementia).