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HealthyNCT00696371

PET Imaging of Peripheral Benzodiazepine Receptors

An observational study of Healthy, run by National Institute of Mental Health (NIMH) at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

This study will use positron emission tomography (PET) to measure a receptor in the brain that is involved in inflammation. It will test two radioactive chemicals used in the procedure to see if the newer chemical, [(11)C]B, is as good or better than the older one, [(11)C]A, for measuring brain inflammation. Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Healthy
How many people
15 participants
Where
1 siteUnited States
Study dates
6 Jun 2008to 19 Aug 2014
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Subjects must be healthy and at least 18 years of age.

Who cannot join

  • Current psychiatric disease, substance abuse or severe systemic disease based on history and physical exam.
  • Laboratory tests with clinically significant abnormalities.
  • Prior participation in other research protocols or clinical care in the last year such that radiation exposure, including that from this protocol, would exceed the guidelines set by the Radiation Safety Committee (RSC).
  • Pregnancy or breast feeding.
  • Positive result on urine screen for illicit drugs.
  • Subjects who cannot lie on their back for extended periods of time.
  • Subjects with significant claustrophobia who cannot tolerate an MRI scan.
  • Subjects with cardiac pacemakers or metal in their bodies.

Trial locations and contacts

1 site in 1 country.

United States1 site
  • National Institutes of Health Clinical Center, 9000 Rockville Pike

    Bethesda, Maryland, 20892

Other trials in United States

About this study

Official title: PET Imaging of Peripheral Benzodiazepine Receptors Using [11C](R)-PK 11195 and [11C]PBR28

This study will use positron emission tomography (PET) to measure a receptor in the brain that is involved in inflammation. It will test two radioactive chemicals used in the procedure to see if the newer chemical, [(11)C]B, is as good or better than the older one, [(11)C]A, for measuring brain inflammation.

Healthy volunteers 18 years of age and older may be eligible for this study. Participants undergo an evaluation, [(11)C]A PET scan, [(11)C]B PET scan and magnetic resonance imaging (MRI), as follows:

Read more

Evaluation

Medical history and physical examination, blood and urine tests

PET scans

  • [(11)C]A scan. A catheter (plastic tube) is placed in an arm vein for injection of the [(11)C]A isotope. Some patients also have a catheter placed in an artery in the wrist to collect arterial blood samples during the scan. Subjects then lie on the scanner bed and a special mask is fitted to the head to help keep the subject s head still during the procedure. Following an 8-minute scan to calibrate the scanner, the [(11)C]A is injected into the catheter in the vein and pictures are taken that show where chemicals related to inflammation are present. The procedure takes about 2.5 hours.
  • [(11)C]B scan. The procedure is the same as above for [(11)C]A, except the isotope used is [(11)C]B.

MRI scan.

This test uses a strong magnetic field and radio waves to obtain images of body organs and tissues. The subject lies on a table that can slide in and out of the scanner (a metal cylinder), wearing earplugs to muffle loud noises that occur during the scan.

...

Read the detailed description

Objective:

In response to brain inflammation, microglia over-express the peripheral benzodiazepine receptor (PBR). Although peripheral organs such as the heart and kidney express PBR constitutively, the brain normally expresses PBR in low numbers. Increased PBR density in the brain therefore signifies a change from a normal state to an active, inflammatory state. Positron emission tomography (PET) imaging can quantify PBR density in vivo using radioligands that bind to PBR sites. One PBR-selective radioligand, [(11)C](R)-PK 11195, has been used to identify areas of brain inflammation in patients with various neurological diseases. Unfortunately, [(11)C](R)-PK 11195 has several limitations, including low specific signal. A recently developed radioligand, [(11)C]PBR28, has higher specificity than [(11)C](R)-PK 11195 for PBR in animal studies. No study to date has compared [(11)C]PBR28 to [(11)C](R)-PK 11195 in human subjects.

In early clinical studies using [(11)C]PBR28, 4 of 32 healthy human subjects had complete absence of radioligand binding, even in peripheral organs that constitutively express PBR. One of these non-binders had specific binding of PBR28 on an in vitro assay using peripheral lymphocytes. We do not know why some subjects have [(11)C]PBR28 binding while others do not. We also do not know why one non-binder had positive in vitro binding and negative in vivo binding on PET imaging. No study has reported absent binding with [(11)C](R)-PK 11195. In order to better understand the phenomenon of non-binding, we need to obtain [(11)C](R)-PK 11195 PET scans in subjects that are [(11)C]PBR28 non-binders.

Study Population:

This protocol will study a total of 30 healthy human volunteers.

Design:

Fifteen subjects will undergo PET imaging with [(11)C]PBR28 and [(11)C](R)-PK 11195 using arterial blood sampling for fully quantitative image analysis. These subjects may have dedicated brain PET imaging or whole body PET imaging.

Fifteen subjects will undergo PET imaging with [(11)C]PBR28 and [(11)C](R)-PK 11195 without arterial blood sampling. These subjects will have whole body PET imaging.

All subjects will have in vitro PBR28 binding assays performed.

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Outcome Measures:

Our primary outcome measures will be the distribution volume and time stability of each radioligand. We also wish to determine if subjects with absent [(11)C]PBR28 binding also have absent [(11)C](R)-PK 11195 binding. The presence or absence of [(11)C]PBR28 and [(11)C](R)-PK 11195 binding will be evaluated in brain and in peripheral organs. Lastly, we will measure in vitro binding of PBR28 by performing binding assays using peripheral blood cells.

Conditions
Healthy
Keywords
Neuroinflammation, PBR28, PET Imaging, Health Volunteer, HV
Medical subject headings
Neuroinflammatory Diseases

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. The first goal of this study is to compare [11C]PBR28 and [11C](R)-PK 11195 as radioligands in the measurement of PBR in healthy human subjects. Our primary outcome measures will be the distribution volume and time stability of each radioligand.

Secondary outcomes (1)
  1. The second goal is to identify non-binders, that is, subjects that do not demonstrate any binding to [11C]PBR28.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted12 Jun 2008 (estimated)
  2. Study start6 Jun 2008
  3. Study completion19 Aug 2014

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Time perspective
Prospective
Enrolment
15 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT00696371
Sponsor's protocol ID
080158
Other IDs
08-M-0158
Status last verified
19 Aug 2014
First submitted
11 Jun 2008
Last updated
17 Dec 2019
Results posted
No

Publications

  • Anholt RR, De Souza EB, Oster-Granite ML, Snyder SH. Peripheral-type benzodiazepine receptors: autoradiographic localization in whole-body sections of neonatal rats. J Pharmacol Exp Ther. 1985 May;233(2):517-26.

    PubMed 2987488
  • Banati RB, Myers R, Kreutzberg GW. PK ('peripheral benzodiazepine')--binding sites in the CNS indicate early and discrete brain lesions: microautoradiographic detection of [3H]PK11195 binding to activated microglia. J Neurocytol. 1997 Feb;26(2):77-82. doi: 10.1023/a:1018567510105.

    PubMed 9181482
  • Banati RB, Newcombe J, Gunn RN, Cagnin A, Turkheimer F, Heppner F, Price G, Wegner F, Giovannoni G, Miller DH, Perkin GD, Smith T, Hewson AK, Bydder G, Kreutzberg GW, Jones T, Cuzner ML, Myers R. The peripheral benzodiazepine binding site in the brain in multiple sclerosis: quantitative in vivo imaging of microglia as a measure of disease activity. Brain. 2000 Nov;123 ( Pt 11):2321-37. doi: 10.1093/brain/123.11.2321.

    PubMed 11050032

Questions about this trial

What is this clinical trial studying?

An observational study of Healthy, run by National Institute of Mental Health (NIMH) at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 17 Dec 2019. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

The first goal of this study is to compare [11C]PBR28 and [11C](R)-PK 11195 as radioligands in the measurement of PBR in healthy human subjects. Our primary outcome measures will be the distribution volume and time stability of each radioligand.. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT00696371, which also lists 3 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Dec 2019.

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