Amyloid Lowering for Alzheimer's in Down's With Donanemab Investigation (NCT06911944) | Clinical Trial Compass
Not Yet RecruitingPhase 4
Amyloid Lowering for Alzheimer's in Down's With Donanemab Investigation
60 participantsStarted 2026-08-01
Plain-language summary
The goal of this clinical trial is to learn if donanemab can reduce levels of amyloid in the brain, and if donanemab is safe and well-tolerated in participants with Down syndrome.
The main questions it aims to answer are: Does donanemab reduce amyloid in the brain? Is donanemab safe and well-tolerated in people with Down syndrome? Researchers will compare donanemab to a placebo (a look-alike substance that contains no drug) to see if donanemab works to reduce levels of amyloid in the brain.
Participants in the study will be 35-50 years old and will be in the study for 12 months. Participants will then stay in the study for an additional 12 months in an long-term extension where all participants will receive donanemab. Participants who had a reduction in amyloid (measured by amyloid brain scan) by the end of the first 12 months will receive placebo for the long-term extension, while participants who did not have an amyloid reduction will receive study donanemab for the long-term extension. Everyone (participants and study staff) will remain blinded to treatment for the duration of the study.
Participants will:
* Have intravenous (IV) infusions of donanemab (or placebo) every 4 weeks
* Visit the clinic once every other month for checkups and tests. These tests will include brain scans (magnetic resonance imaging \[MRI\] and positron emission tomography \[PET\] ), blood draws and memory tests.
* Have a study partner who who can provide information about the participant and can join participant for some of the study visits.
Who can participate
Age range35 Years – 50 Years
SexALL
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Inclusion criteria
✓. Documentation of the participant's informed consent to study procedures
✓. Ages 35-50 years (inclusive).
✓. Plasma Phosphorylated tau (pTau) 217 levels at screening consistent with amyloid PET eligibility.
✓. Diagnosis of Down syndrome (including trisomy 21, mosaic trisomy 21, Robertsonian translocation trisomy 21, or partial trisomy 21) as confirmed by medical record review or Karyotype genetic testing.
✓. Intelligence quotient (IQ) equal to or greater than 40 based on Kaufman Brief Intelligence Test, Second Edition.
✓. Participants must be in good general health as evidenced by medical history with no diagnosis of dementia.
✓. Elevated brain amyloid (\>18 centiloids) at screening.
✓. Stable dose of permitted medications as described protocol for 4 weeks prior to screening.
Exclusion criteria
✕. Females who are lactating or pregnant (as confirmed by a urine pregnancy test) during screening, or plan to become pregnant during the study.
✕. Females of childbearing potential or males with a female partner of childbearing potential who did not use a highly effective method of contraception within 28 days of screening alongside with a suitable barrier method (e.g., male condom) and/or are not willing to use both methods for the duration of their participation in the study and for 3 months after the last dose of study drug.
✕. Weight less than 40kg at screening.
✕. Lack of good venous access such that intravenous (IV) drug delivery or multiple blood draws would be precluded.
✕. Suspected or known allergic reactions, adverse reactions, or hypersensitivity to humanized monoclonal antibodies or any components of the study treatments (donanemab or placebo).
✕. Previous treatment with donanemab unless there is firm evidence that the participant received placebo only.
✕. Prior or current treatment with a prohibited medication as described in protocol.
✕. 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.