A Phase 1/2 interventional study of SV2A PET and TSPO PET in HIV Associated Neurocognitive Disorder, HIV Dementia and HIV Encephalitis, sponsored by Yale University. Recruiting at 1 site in United States. Open to participants aged 18 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-14.
Sponsored by Yale University · Phase 1/2, Interventional, and Basic science
The purpose of this study is to longitudinally characterize and evaluate changes in synaptic density in the brain using novel positron-emission tomography (PET) scans; magnetic resonance imaging (MRI), and clinical laboratory markers associated with HIV-related injury in the central nervous system. This study will test hypotheses relating to the presence and mechanisms of aberrant brain structure at the synaptic level in living humans with virologically controlled HIV on antiretroviral therapy. To evaluate associations between PET imaging radiotracers [11C]UCB-J, a ligand for presynaptic vesicle protein 2A (SV2A), a vesicle membrane protein expressed in synapses, and PET [11C]PBR28 a measure of microglia function in the brain, the Yale PET center has developed an advanced approach of combining multiple distinct ligands in coordinated same-day PET imaging. Additionally, the study will evaluate the associations of this novel synaptic density marker with well-established clinical measures of neurocognitive performance and laboratory measures of blood and cerebrospinal fluid (CSF).
The HIV PET plus study builds upon the compelling preliminary findings of the investigators HIV PET pilot study (Yale Internal Review Board (IRB) #2000024620) that brain SV2A PET successfully identifies regions of reduced synaptic density, including a hippocampal-frontostriatal neural circuit that is relevant to central nervous system (CNS) dysfunction in PLWH on ART
The primary aims of this study are as follows:
Aim 1. To evaluate cross-sectional differences and 24-month longitudinal changes in synaptic density in PLWH on suppressive ART relative to matched HIV-negative (HIV-) controls. Synaptic density will be measured with SV2A PET scans acquired at baseline and two years in 40 PLWH on ART and in 30 HIV-, matched for age, gender, ethnicity, and history of substance use.
Hypotheses: (1a) Synaptic density in a hippocampal-frontostriatal neural circuit will be reduced in PLWH relative to matched HIV-; (1b) Synaptic density in this circuit will decline at a greater rate in PLWH relative to HIV-.
Aim 2. To determine, in PLWH on ART, the extent to which microglia levels impact synaptic density. Microglia levels will be measured with TSPO PET scans concurrently acquired with SV2A PET scans in a subset of 20 PLWH from Aim 1 at baseline, followed by repeat SV2A PET scans at 24 months.
Hypotheses: (2a) Greater microglia levels in a hippocampal-frontostriatal circuit will be associated with decreased synaptic density in this circuit; and (2b) Greater microglial levels at baseline will be a longitudinal predictor of a greater decline in synaptic density in this neural circuit over 24 months.
Aim 3. To determine the role of synaptic density in mediating the relation between microglia level, laboratory biomarkers of inflammation and neuronal injury, and neurocognitive functioning in PLWH. Blood, cerebrospinal fluid, and neurocognitive measures will be acquired in 40 PLWH on ART at baseline and 2 years with SV2A PET. The investigators will use parallel processing statistical approaches to examine multimodal longitudinal associations between baseline microglial activation, and changes in synaptic density, laboratory biomarkers and neurocognitive functioning to understand the molecular neuropathogenesis of CNS impairment in PLWH on ART.
Hypothesis: (3) In PWLH on ART, greater hippocampal-frontostriatal microglial activation at baseline will be associated with greater 24-month reductions in synaptic density, which will in turn be associated with greater reductions in neurocognitive functioning, particularly on measures of learning and memory.
41 studies on the registry are indexed under AIDS Dementia Complex; 2 are open to participants now.
This study's planned enrollment of 70 is above the median of 50 across 31 interventional studies indexed under AIDS Dementia Complex.
Browse AIDS Dementia Complex studies →Yale University is the lead sponsor of 1,770 studies on the registry; 294 are open to participants now.
Of its 221 completed or terminated interventional studies of FDA-regulated products, 129 (58%) have results posted.
Counted across the registry records on this site, refreshed daily.
PLWH Inclusion Criteria:
PLWH Exclusion Criteria:
HIV - Inclusion Criteria:
HIV- Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
40 PLWH participants will be scanned using anatomical magnetic resonance imaging (MRI) and undergo two SV2A (11C-UCB-J) PET scans with arterial sampling and full radio metabolite analysis to obtain measures of synaptic density at baseline and 24 months (2 years). For each SV2A PET, up to 20 millicurie (mCi) of \[11C\], UCB-J will be administered by an intravenous line (IV) with a scan duration of up to 120 minutes. A subset of PLWH (n=20) will participate in TSPO (11C-PBR28) PET scans on the same day as the baseline SV2A PET scan. For a TSPO PET, up to 20 mCi of \[11C\], PBR28 will be administered by an intravenous line (IV) with a scan duration of up to 120 minutes.
Drug: SV2A PET · Drug: TSPO PET
30 HIV-Negative Control (HIV-) participants will be scanned using anatomical magnetic resonance imaging (MRI) and undergo two SV2A (11C-UCB-J) PET scans with arterial sampling and full radio metabolite analysis to obtain measures of synaptic density at baseline and 24 months (2 years). For each SV2A PET, up to 20 mCi of \[11C\], UCB-J will be administered by an intravenous line (IV) with a scan duration of up to 120 minutes. A subset of will participate in TSPO (11C-PBR28) PET scans on the same day as the baseline SV2A PET scan. For a TSPO PET, up to 20 mCi of \[11C\], PBR28 will be administered by an intravenous line (IV) with a scan duration of up to 120 minutes.
Drug: SV2A PET
SV2A PET scan with radiotracer \[11C\]UCB-J for imaging synaptic density in the brain
Also known as: [11C]UCB-J, [11C]APP311
TSPO PET scan with radiotracer \[11C\]PBR28 for imaging of neuroimmune status
Also known as: [11C]PBR28
The primary outcome measure for 11C-UCB-J will be the binding potential of 11C-UCB-J, specifically non-displaceable binding potential (BPND), the ratio of the specifically bound radioligand to that of nondisplaceable radioligand in tissue.
Preliminary data from the investigators' pilot study revealed SV2A PET imaging with radiotracer 11C-UCB-J identified regions of reduced synaptic density in suppressed PLWH compared to matched HIV-negative controls. PET and MRI imaging data will be processed for quantification of 11C-UCB-J imaging data in a larger group of suppressed PLWH compared to matched HIV-negative controls to test-retest reproducibility of 11C-UCB-J.
Time frame: Through study completion date, an average of 5 years.
Change in cross-sectional differences and 24-month longitudinal changes in synaptic density in PLWH on suppressive ART relative to matched HIV-negative controls
Baseline and 24 Month PET and MRI imaging data will be processed for a linear mixed-effects model (LMM) to compare changes in hippocampal-frontostriatal 11C-UCB-J BPND between PLWH and healthy controls.
Time frame: Baseline and 24 months
Plan to share: No
No publications or documents are linked to this record.
Started May 2023 (actual). Primary completion is estimated for Dec 2028, 67 months after the start.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Studies of the drug tested here: APP-311 C-11