Biodistribution and Pathophysiology Study of 11C-para-aminobenzoic Acid

Phase 1 Biodistribution and Pathophysiology Study of 11C-para-aminobenzoic Acid (11C-PABA)

The investigators will perform radionuclide PET scans in subjects with infectious diseases to assess whether radio-labeled PABA (11C-PABA) is effective for infection imaging.

Tomographic imaging can be used to evaluate disease processes deep within the body, noninvasively and relatively rapidly. The goal is to see if this imaging technique can help differentiate infections from non-infectious processes and also provide information on the causative bacterial class.

Study Overview

• Status: Completed
• Conditions: Bacterial Infections; Inflammatory Disease; Renal Excretion; Oncologic Disease
• Intervention / Treatment: Combination product: 11C-para-aminobenzoic acid PET/CT; Drug: Probenecid

• Study Type: Observational
• Enrollment (Actual): 13

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Baltimore, Maryland, United States, 21218
      • Johns Hopkins Medical Institutions

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

Patients with bacterial infections or non-infectious processes such as inflammatory / oncologic diseases will be enrolled. Males and female members of all races and ethnic groups are eligible for this trial and encouraged to participate.

Description

Inclusion Criteria:

1. Male or female ≥18 years of age at the time of consent and imaging.

2. Healthy subjects OR those with confirmed (microbiologically, molecular or serological testing) diagnosis of infection at any body site OR clinical and imaging evidence of suspected infection in any body site with confirmation (microbiologically, molecular or serological testing) anticipated within 72 hours of imaging.

   OR subjects with confirmed inflammatory (rheumatoid arthritis, idiopathic pulmonary fibrosis, etc) or oncologic (e.g. localized or metastatic tumors) disease and clinically determined not to have infection.

3. For subjects with infections:

   Non mycobacterium tuberculosis infections: received no more than 7 days of effective antibiotic treatment, as judged by the attending and/or principal investigator.

   OR Mycobacterium tuberculosis or mycobacteroides infections: received no more than 4 weeks of effective treatment. Infection confirmed by positive culture or molecular testing.

4. For inpatients, determined by the attending of record to be stable to participate in the study (will be documented in the research records).
5. Subject is judged by the investigator to have the initiative and means to be compliant with the protocol.
6. Subjects or their legal representatives must have the ability to read, understand and provide written informed consent for the initiation of any study related procedures. Adults lacking capacity will not be enrolled in this study.

Exclusion criteria:

Within 28 or fewer days prior to imaging, a complete blood count with differential, blood comprehensive metabolic panel will be performed. Subjects will be excluded from enrollment if any of the following apply:

1. Reported pregnancy or pregnancy as determined by positive or indeterminate serum human chorionic gonadotrophin (hCG) at screening and positive urine hCG prior to radiopharmaceutical dosing.
2. Lactating females.
3. Inadequate venous access.
4. Screening clinical laboratory values must be within normal limits or judged not clinically significant by the principal investigator.
5. Administered a radioisotope within 5 physical half-lives prior to study enrollment.
6. Subject has been treated with an investigational drug / biologic / therapeutic device within 30 days prior to study radiotracer administration.
7. Determined to have prior (external) radiation exposure which will exceed RDRC annual radiation exposure limit of 5 rems.

8. For patients undergoing renal imaging they will be excluded if any of the following conditions exist:

   • Hypertension
   • Diabetes mellitus type I or II
   • Body mass index less than 18.5 kg/m2 or higher than 30 kg/m2
   • Family history of renal disease
   • Urinary tract infection in the prior 6 months

Study Plan

How is the study designed?

Design Details

• Observational Models: Other
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
11C-para-aminobenzoic acid PET/CT	Combination product: 11C-para-aminobenzoic acid PET/CT; A bolus of 20 mCi of 11C-PABA followed by PET/CT; Drug: Probenecid; Oral dose of 500 mg (tablet) 2 hours before IV dose of 11C-PABA will be administered.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pathophysiology of 11C-PABA in diseased subjects	Reconstruction of the PET data will be performed by means of iterative reconstruction (IR) by the ordered subset-expectation-maximization (OSEM) method with CT attenuation correction.	Up to 3 hours
Biodistribution of 11C-PABA in diseased subjects	Reconstruction of the PET data will be performed by means of iterative reconstruction (IR) by the ordered subset-expectation-maximization (OSEM) method with CT attenuation correction.	Up to 3 hours

Collaborators and Investigators

• Sponsor: Johns Hopkins University
• Collaborators: National Heart, Lung, and Blood Institute (NHLBI)
• Investigators: Principal Investigator: Sanjay K Jain, MD, Johns Hopkins University

Study record dates

Study Major Dates

• Study Start (Actual): December 22, 2023
• Primary Completion (Actual): November 8, 2025
• Study Completion (Actual): November 8, 2025

Study Registration Dates

• First Submitted: November 3, 2022
• First Submitted That Met QC Criteria: November 3, 2022
• First Posted (Actual): November 10, 2022

Study Record Updates

• Last Update Posted (Actual): December 12, 2025
• Last Update Submitted That Met QC Criteria: December 8, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: PET/CT; Probenecid; 11C-PABA
• Additional Relevant MeSH Terms: Infections; Bacterial Infections and Mycoses; Bacterial Infections; Sulfur Compounds; Organic Chemicals; Amides; Sulfonamides; Sulfones; Probenecid
• Other Study ID Numbers: IRB00179210; R01HL131829 (U.S. NIH Grant/Contract)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No