Key Inclusion Criteria:

   - Consented to receive disclosure of their risk estimates to develop clinical symptoms
   of AD based on their APOE genotype.

   - Male or female, age 60 to 75 years inclusive. Females were to be post-menopausal.

   - Mini-Mental State Examination (MMSE) total score ≥ 24 and cognitively unimpaired as
   evaluated by memory tests

   - Homozygous APOE4 genotype.

   - Participant willing to have a study partner.

Key Exclusion Criteria:

   - Any disability that prevented the participant 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 may 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 60 months
   prior to screening.

   - History of hypersensitivity to any of the investigational drugs or their excipients /
   adjuvant or to drugs of similar chemical classes.

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

   - Contraindication or intolerance to MRI or PET investigations (with fluorinated radio
   ligands).

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

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

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

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

   - Current clinically significant ECG findings. For Cohort - I only: Participants with
   previous organ transplantation or stem cell transplantation, or indication for
   treatment with anti-coagulants.

For Cohort - II only: Participants with depigmenting or hypopigmenting conditions (e.g.
albinism vitiligo) or active / history of chronic urticarial in the past year.