A Study of CNP520 Versus Placebo in Participants at Risk for the Onset of Clinical Symptoms of Alzheimer's Disease

Inclusion Criteria:

   - consent to receive disclosure of their risk estimates to develop clinical symptoms of
   AD based on their APOE genotype and, if Heterozygotes, evidence of elevated brain
   amyloid.

   - Male or female, age 60 to 75 years inclusive. Females must be considered
   post-menopausal and not of child bearing potential

   - Cognitively unimpaired as evaluated by memory tests performed at screening.

   - Participant's willingness to have a study partner.

   - Carrier of at least one APOE4 gene if Heterozygotes, elevated brain amyloid (as
   measured by CSF Abeta or amyloid PET imaging).

Exclusion Criteria:

   - Any disability that could have prevented the participants from completing all study
   requirements. -

   - Current medical or neurological condition that could have impacted cognition or
   performance on cognitive assessments.

   - Advanced, severe progressive or unstable disease that could have interfered with the
   safety, tolerability and study assessments, or put the participant at special risk.

   - History of malignancy of any organ system, treated or untreated, within the past 60
   months.

   - Indication for, or current treatment with ChEIs and/or another AD treatment (e.g.
   memantine).

   - Contraindication or intolerance to MRI.

   - Brain MRI results showing findings unrelated to AD that, in the opinion of the
   Investigator might be a leading cause to future cognitive decline, could have posed a
   risk to the participant, or could have prevented a satisfactory MRI assessment for
   safety monitoring.

   - Suicidal Ideation in the past six months, or Suicidal Behavior in the past two years.

   - A positive drug screen at Screening, if, in the Investigator's opinion, was is due to
   drug abuse.

   - Significantly abnormal laboratory results at Screening, not as a result of a temporary
   condition.

   - Current clinically significant ECG findings.

   - Clinically relevant depigmenting or hypopigmenting conditions (e.g. albinism,
   vitiligo) or active / history of chronic urticaria in the past year.