Eligibility Details:
Inclusion Criteria:
1. Total body weight between 50 and 120 kg, inclusive.
2. Clinical laboratory evaluations (including chemistry panel fasted [fasted at least 8
hours], complete blood count (CBC), and urine analysis) within the reference range for
the test laboratory, unless deemed not clinically significant by the Investigator. A
count of the segmented neutrophils and bands should be performed when results from the
white blood cells (WBCs) are not within the reference range.
3. Negative test for selected drugs of abuse at screening (does not include alcohol) and
at admission (testing at admission does include alcohol breath test). A positive
result may be verified by re-testing (up to one false positive result permitted) and
may be followed up at the discretion of the Investigator.
4. Females must be non-pregnant and non-lactating, and either surgically sterile
5. In good health, determined by no clinically significant findings from medical history,
physical examination, 12-lead electrocardiogram (ECG), laboratory tests, and vital
signs.
For MD cohort
1. Ages 50-85 years, inclusive.
2. The participant should be capable of completing assessments either alone or with the
help of the study partner (where appropriate), per local guidelines.
3. Availability of a person ("study partner") who, in the Investigator's judgment, has
frequent and sufficient contact with the participant and is able to provide accurate
information regarding the participant's cognitive and functional abilities, agrees to
provide information at clinic visits, which require partner input for scale
completion, and signs the necessary consent form, per local guidelines.
4. Clinical diagnosis of probable Alzheimer's disease dementia based on National
Institute on Aging Alzheimer's Association criteria.
Exclusion Criteria:
1. Pregnant or lactating, or intending to become pregnant within 16 weeks after last dose
of study drug.
2. Participation in a clinical trial within 30 days before randomization; use of any
experimental oral therapy within 30 days or 5 half-lives prior to Day 1, whichever is
greater; or use of any biologic therapy within 12 weeks or 5 half-lives prior to Day
1, whichever is greater. Participants who have received an experimental therapy that
has no half-life, like a vaccine, should have completed that therapy at least 12 weeks
prior to Day 1. Participants who have received an experimental vaccine against a
central nervous system (CNS) target, such as beta-amyloid or tau, are not eligible for
this study.
3. Any non-experimental vaccine within 2 weeks of randomization, until 2 weeks after the
last dose. It is advised that prospective participants receive their annual influenza
vaccine as early as possible in advance of the flu season, and then wait 2 weeks prior
to randomization. It is permitted to receive the annual influenza vaccine during the
screening period.
4. Surgery or hospitalization during the 4 weeks prior to screening.
5. Planned procedure or surgery during the study.
6. Systemically, clinically significantly immunocompromised patients, owing to continuing
effects of immune suppressing medication.
7. Known history of severe allergic, anaphylactic, or other hypersensitivity reactions to
chimeric, human, or humanized antibodies or fusion proteins.
8. Past history of seizures, with the exception of childhood febrile seizures.