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 ofAD based on their APOE genotype and, if Heterozygotes, evidence of elevated brainamyloid.
• Male or female, age 60 to 75 years inclusive. Females must be consideredpost-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 (asmeasured by CSF Abeta or amyloid PET imaging).

Exclusion Criteria:

• Any disability that could have prevented the participants from completing all studyrequirements. -
• Current medical or neurological condition that could have impacted cognition orperformance on cognitive assessments.
• Advanced, severe progressive or unstable disease that could have interfered with thesafety, tolerability and study assessments, or put the participant at special risk.
• History of malignancy of any organ system, treated or untreated, within the past 60months.
• 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 theInvestigator might be a leading cause to future cognitive decline, could have posed arisk to the participant, or could have prevented a satisfactory MRI assessment forsafety 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 todrug abuse.
• Significantly abnormal laboratory results at Screening, not as a result of a temporarycondition.
• 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.