Evaluation of [11C]ZTP-1 to Image PDE4B

September 17, 2026 updated by: National Institute of Mental Health (NIMH)

Background:

PDE4B is a protein in cells that helps turn off certain chemical signals after they ve done their job. It controls inflammation, immune responses, and some brain signaling. Measuring PDE4B levels in the body can help doctors manage a disease or know if a treatment is working. Researchers want to find out if a new tracer (a radioactive substance injected during imaging scans) can help them measure PDE4B in people more effectively.

Objective:

To test a new tracer ([11C]ZTP-1) during imaging scans of the brain and body in healthy people.

Eligibility:

Healthy people aged 18 and older. They must have been screened under protocols 01M-0254 or 17M0181.

Design:

Participants will have either 1 or 2 clinic visits.

During their first visit, all participants will have a positron emission tomography (PET)/computed tomography (CT) scan. Prior to the scan, they will have blood and urine tests and a test of their heart function. The study tracer will be given through a tube attached to a needle inserted into a vein in the arm. They will lie on a padded bed that fits inside a doughnut-shaped machine; the machine uses x-rays to create images of the inside of the body.

Some participants will have a PET/CT scan of their whole body. They will need only 1 visit. The visit will last up to about 8 hours.

Some participants will have a PET/CT scan of only their brain. They will also have a magnetic resonance imaging (MRI) scan of the brain. They may need to return for a second visit for the MRI scan.

Participants will receive a follow-up call to check on their well-being after their PET/CT scans.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Study Description:

This study is intended to provide information on the novel [11C]ZTP-1 radioligand and its ability to localize and measure PDE4B in the brain and body of healthy volunteers.

Objectives:

Primary Objective: To study the brain uptake of [11C]ZTP-1 and perform kinetic modeling of [11C]ZTP-1 in healthy volunteers.

Secondary Objective: To study brain retest variability and reliability, biodistribution, and dosimetry of [11C]ZTP-1 in healthy volunteers.

Endpoint:

Primary Endpoint: PDE4B density measured as distribution volume (VT), derived from kinetic modeling of [11C]ZTP-1 in the brain.

Secondary Endpoint: PDE4B density measured as distribution volume (VT) , evaluated in terms of test retest variability (absolute variability) and reliability (intraclass correlation coefficient [ICC]). Whole-body biodistribution and radiation burden, measured as Effective Dose (ED).)

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
40

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • Recruiting
        • National Institutes of Health Clinical Center
        • Contact:
          • NIH Clinical Center Office of Patient Recruitment (OPR)
          • Phone Number: TTY dial 711 800-411-1222
          • Email: ccopr@nih.gov

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

  • INCLUSION CRITERIA:

To be eligible to participate in this study, an individual must meet the following criteria:

  • Aged 18 years or older.
  • Must have undergone a screening assessment under protocol 01M-0254, "The Evaluation of Patients with Mood and Anxiety Disorders and Healthy Participants or protocol 17M0181 Recruitment and Characterization of Healthy Research Volunteers for NIMH Intramural Studies."
  • Be healthy based on medical history, physical examination, and laboratory testing.
  • Able to provide informed consent.
  • Willingness to complete all study procedures including MRI tests.
  • Have had their radial artery pulse checked for the presence of adequate ulnar collateral flow and the absence of any metal or foreign objects in both wrists.
  • Agree to adhere to the lifestyle considerations

EXCLUSION CRITERIA:

An individual who meets any of the following criteria will be excluded from participation in this study:

  • Clinically significant abnormalities on EKG or laboratory testing. This includes CBC and acute care panel (Na, K, Cl, CO2, creatinine, glucose, urea nitrogen).
  • History of neurologic illness or injury with the potential to affect study data interpretation.
  • History of seizures, other than in childhood and related to fever.
  • Recent exposure to radiation (i.e., PET from other research) that, when combined with this study, would be above the allowable limits.
  • Inability to lie flat on camera bed for at least two hours, including claustrophobia and weight greater than the maximum for the scanner (500 lbs).
  • HIV infection.
  • Pregnancy or breastfeeding.
  • Must not have substance use disorder or alcohol use disorder.
  • Unable to travel to the NIH.
  • Unable to have an MRI scan (e.g., because of pacemakers or other implanted electrical devices, brain stimulators, dental implants, aneurysm clips (metal clips on the wall of a large artery), metallic prostheses (including metal pins and rods, heart valves, and cochlear implants), permanent eyeliner, implanted delivery pumps, shrapnel fragments, or metal fragments in the eye.
  • Known hypersensitivity to phosphodiesterase-4 (PDE-4) inhibitors (e.g. apremilast, roflumilast, nerandomilast, crisborole).
  • Taking CYP3A4 inhibitors (e.g. grapefruit juice, clarithromycin, erythromycin, ritonavir); CYP3A4 inducers (e.g. phenobarbital St. John's Wort, rifampicin) or oral contraceptives containing gestodene and ethinyl estradiol.

EXCLUSION OF CHILDREN:

Inclusion of children is not appropriate, because this protocol has more than minimal risk from radiation exposure without the possibility of direct benefit.

EXCLUSION OF PREGNANT OR BREASTFEEDING WOMEN:

Pregnant women will be excluded because this protocol involves exposure to ionizing radiation. Lactating women will be excluded because radioisotopes may be excreted in milk. We will perform a pregnancy test at screening and prior to all procedures to ensure participants are not pregnant. The test must be negative in order to continue on the study. In addition to completing a negative urine pregnancy test, on the day of PET scanning prior to PET scan procedures, participants of childbearing potential will undergo a clinical pregnancy screening interview with a licensed independent practitioner to confirm lack of pregnancy.

EXCLUSION OF PARTICIPANTS WHO ARE HIV POSITIVE:

Persons with HIV infection are excluded because HIV infection itself may change cAMP signaling.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: One-arm
All subjects will receive the same tests.
Drug: 11C-ZTP-1
Injected IV followed by PET scanning

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Total Volume of Distribution
Time Frame: 120 minutes
Quantification of 11C-ZPT-1
120 minutes

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Dosimetry, ICC, aTRV, and biodistribution.
Time Frame: 120 minutes
Quantification of 11C-ZPT-1
120 minutes

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
National Institute of Mental Health (NIMH)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Robert B Innis, M.D., National Institute of Mental Health (NIMH)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 1, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 19, 2029

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 3, 2030

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 3, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 3, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 4, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 18, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 17, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
September 16, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 10002536
  • 002536-M

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

The results will be submitted to ClinicalTrials.gov

IPD Sharing Time Frame

18 months after closure of protocol.

IPD Sharing Access Criteria

BTRIS

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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