A Molecular and Functional Brain Imaging Study in Individuals With Down Syndrome and Healthy Controls Following Single Dose RG1662

Study Overview
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Brief Summary
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This single-center, single-blind, placebo-controlled, parallel-group study with crossover component will evaluate the GABAAalpha5 receptor expression, occupancy and functional connectivity in the brains of individuals with Down syndrome and healthy controls following single dose RG1662. Participants will receive a single dose of placebo before the imaging session (PET and MRI), and a single dose of RG1662 before the second imaging session.

Official Title
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A Single-center, Single Blind Molecular and Functional Imaging Study to Assess GABAAalpha5 Receptor Expression, Occupancy and Functional Connectivity in the Brains of Individuals With Down Syndrome and Healthy Controls Following a Single Oral Administration of RG1662 or Placebo

Conditions
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Healthy Volunteer, Down Syndrome

Intervention / Treatment
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* Drug: RG1662
* Drug: placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy controls and individuals with Down syndrome: Male and female adults, 18 to 40 years of age Body mass index (BMI) 18 - 40 kg/m2 inclusive Females of child-bearing potential and males with female partners of child-bearing potential must agree to use two medically approved methods of contraception, one of which must be a barrier method, for the duration of the study and for 4 months after the last study drug administration Clinical laboratory values within normal limits or abnormalities considered not significant by the investigator and sponsor; individuals with thyroid disease may be included in the study provided they are euthyroid and stable on treatment for at least one month prior to screening Individuals with Down syndrome must also meet the following: Diagnosis of Down syndrome confirmed by karyotype; subjects may have free trisomy 21 or Robertsonian translocations; mosaic Down syndrome will be excluded Individuals must have a parent or other reliable caregiver who agrees to accompany the inidvidual to all clinic visits, provide information about the individual as required by protocol, and be willing to give informed consent Exclusion Criteria: Regular smoker (>5 cigarettes or equivalent: 3 cigars, 6 cigarillos, 3 pipes per day) Concomitant disease or condition or any clinically significant finding at screening that could interfere with, or for which the treatment might interfere with the conduct of the study, or that would, in the opinion of the investigator, pose an unacceptable risk to the subject in this study Severe head trauma or CNS infections (e.g. meningitis) History of epilepsy or seizures other than benign febrile convulsions of childhood Any confirmed significant allergic reactions against any drug, anaphylaxis or severe environmental allergies as judged by the investigator Positive for hepatitis B, hepatitis C or HIV infection Positive urine test at screening or at follow-up for drugs of abuse, or positive alcohol breath test at screening and prior to dosing Previous inclusion in research and/or medical protocol involving nuclear medicine, PET or radiological investigations with significant radiation burden (as defined by protocol) Pregnant or lactating women Individuals with evidence or meeting clinical diagnosis of dementia

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br> | Drug: placebo<br>* Single oral dose<br>|
| Experimental: RG1662<br> | Drug: RG1662<br>* Single oral dose<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Brain GABAA receptor alpha5 subunit localization/density assessed by positron emission tomography (PET) |  | approximately 1 day | 
| Brain GABAA receptor alpha5 subunit occupancy following single dose of RG1662 |  | approximately 1 day | 
| Correlation of RG1662 plasma concentrations and GABAAalpha5 receptor occupancy |  | approximately 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Safety: Incidence of adverse events |  | approximately 12 months | 
| Resting state functional brain connectivity following a single dose of either RG1662 or placebo, assessed by functional magnetic resonance imaging (fMRI) |  | approximately 1 day | 
| Functional brain connectivity of individuals with Down syndrome versus healthy controls receiving placebo |  | approximately 12 months |