99mTc-PSMA-I&S Biodistribution in Patients With Prostate Cancer

March 11, 2026 updated by: Jonsson Comprehensive Cancer Center

99mTc-PSMA-I&Amp;S in Patients With Prostate Cancer: An Exploratory Biodistribution Study With Histopathology Validation

This exploratory study conducted under the RDRC program studies the biodistribution of 99mTc-PSMA-I&S in patients with prostate cancer who undergo pelvic lymph node dissection. Prostate specific membrane antigen (PSMA)-targeted radio-guided surgery uses the preoperative intravenous administration of a PSMA-ligand called PSMA-imaging and surgery (I&S) labeled with the gamma-emitter radioisotope Technetium-99m (99mTc). Giving 99mTc-PSMA-I&S may detect PSMA-expressing lymph nodes during surgery using a gamma probe and may help guide doctors to detect prostate cancer that has spread to the lymph nodes.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

PRIMARY OBJECTIVE:

I. To define the biodistribution of 99mTc-based PSMA imaging and surgery agent (99mTc-PSMA-I&S) in normal and malignant tissues of patients with prostate cancer (PCa) with histopathology validation, when available.

SECONDARY OBJECTIVES:

I. To correlate the 99mTc-PSMA-I&S accumulation within tumor lesions observed by in-vivo single-photon emission computed tomography (SPECT), ex-vivo gamma measurements and level of prostate-specific membrane antigen (PSMA) expression quantified by histopathology, when available.

II. To define the best time-point for radio-guided surgery (RGS) with the highest tumor-to-background ratio following 99mTc-PSMA-I&S administration.

OUTLINE:

The first 5 patients receive an initial dose of 99mTc-PSMA-I&S intravenously (IV) followed by 5 SPECT/CT scans at 3-5, 5-20, 17-21, 25-29, and 40-46 hours later. These 5 patients then receive a second dose of 99mTc-PSMA-I&S IV and then undergo standard of care surgery. All subsequent patients receive one dose of 99mTc-PSMA-I&S IV before surgery.

Study Type

Interventional

Enrollment (Estimated)

30

Phase

  • Early 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 Backup

Study Locations

  • United States
    • California
      • Los Angeles, California, United States, 90095
        • Recruiting
        • UCLA / Jonsson Comprehensive Cancer Center
        • Principal Investigator:
          • Jeremie Calais, MD
        • Contact:
        • Contact:

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

Ages Eligible for Study

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Men with PCa (primary or recurrent disease)
  • Men who received a 68Ga-PSMA-11 positron emission tomography (PET)/computed tomography (CT) for staging or restaging
  • Men with evidence of lymph nodes (LNs)-positive disease on 68Ga-PSMA-11 PET/CT
  • Men who are scheduled for pelvic LN dissection (PLND)
  • Men who can provide oral and written informed consent
  • Men who can comply with study procedures

Exclusion Criteria:

  • Patients who started any PCa treatment between study enrollment and surgery
  • Technically inaccessible nodal location

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: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Diagnostic (99mTc-PSMA-I&S, SPECT/CT)
The first 5 patients receive an initial dose of undergo 99mTc-PSMA-I&S IV followed by 5 SPECT/CT scans at 3-5, 5-20, 17-21, 25-29, and 40-46 hours later. These 5 patients then receive a second dose of 99mTc-PSMA-I&S IV and then undergo standard of care surgery. All subsequent patients receive one dose of 99mTc-PSMA-I&S IV before standard of care surgery.
Procedure: Computed Tomography
Undergo SPECT/CT
Other Names:
  • CT
  • CAT
  • CAT Scan
  • Computerized Axial Tomography
  • Computerized Tomography
  • CT Scan
  • tomography
Procedure: Single Photon Emission Computed Tomography
Undergo SPECT/CT
Other Names:
  • Medical Imaging, Single Photon Emission Computed Tomography
  • Single Photon Emission Tomography
  • single-photon emission computed tomography
  • SPECT
  • SPECT imaging
  • SPECT SCAN
  • SPET
  • tomography, emission computed, single photon
  • Tomography, Emission-Computed, Single-Photon
Drug: 99mTc-based PSMA Imaging and Surgery Agent
Given via IV injection

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
The biodistribution of 99mTc-PSMA-I&S in normal and malignant tissues of patients with prostate cancer will be measured by average and maximum standardized uptake value (SUVmean and SUVmax)
Time Frame: time from injection to imaging (range: 1-46 hours)
time from injection to imaging (range: 1-46 hours)

Secondary Outcome Measures

Outcome Measure
Time Frame
99mTc-PSMA-I&S accumulation within tumor lesions observed by in-vivo SPECT (SUVmean and SUVmax) will be correlated with ex-vivo gamma measurements (counts/minute) and level of PSMA expression quantified by histopathology (IHC score)
Time Frame: time from injection to imaging (range: 1-46 hours)
time from injection to imaging (range: 1-46 hours)
The best time-point for 99mTc-PSMA-I&S radioguided surgery will be determined by the tumor-to-background uptake ratio (TBR) using the time-activity curve function
Time Frame: time from injection to imaging (range: 1-46 hours)
time from injection to imaging (range: 1-46 hours)

Collaborators and Investigators

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

Sponsor

Jonsson Comprehensive Cancer Center

Investigators

  • Principal Investigator: Jeremie Calais, MD, UCLA / Jonsson Comprehensive Cancer Center

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)

April 27, 2021

Primary Completion (Estimated)

June 1, 2026

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

April 1, 2021

First Submitted That Met QC Criteria

April 20, 2021

First Posted (Actual)

April 23, 2021

Study Record Updates

Last Update Posted (Actual)

March 13, 2026

Last Update Submitted That Met QC Criteria

March 11, 2026

Last Verified

March 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 20-002256 (UCLA / Jonsson Comprehensive Cancer Center)
  • NCI-2021-01793 (Registry Identifier: CTRP (Clinical Trial Reporting Program))

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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