POSLUMA PET Imaging for PI-RADS 3 Prostate Lesions (PRISM)

October 29, 2026 updated by: SimonMed Imaging

Targeting the Gray Zone: Early Detection of Clinically Significant Prostate Cancer in PI-RADS 3 Patients Using PET Imaging With an 18F-Labeled Radiohybrid PSMA-Targeted Imaging Agent

This prospective, multicenter diagnostic accuracy study will evaluate whether POSLUMA (flotufolastat F 18) PET/MRI or PET/CT can detect clinically significant prostate cancer, defined as Gleason score 7 or higher, in adult men with PI-RADS 3 lesions on recent multiparametric MRI and a clinical indication for prostate biopsy. Participants will undergo a research-only POSLUMA PET scan before targeted and systematic prostate biopsy. PET imaging metrics and clinical variables will be compared with histopathology. Research PET results will not be used to guide clinical management or replace standard diagnostic procedures.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Men aged 18 years or older with a PI-RADS 3 lesion identified on multiparametric MRI within the prior 4 weeks and a clinical indication for prostate biopsy will be consecutively enrolled. After written informed consent, participants will undergo POSLUMA PET/MRI or PET/CT. POSLUMA will be administered as an intravenous bolus at 296 MBq (8 mCi), and imaging will begin approximately 60 minutes after administration. PET-derived metrics, including SUVmax, PRIMARY score, lesion-to-background ratio, and lesion volume, will be recorded. MRI features and clinical parameters, including PSA, PSA density, and free-to-total PSA ratio, may also be collected.

The reference standard will be histopathology from targeted biopsy of the PI-RADS 3 lesion together with systematic prostate biopsy. Diagnostic performance will be evaluated using lesion-level area under the receiver operating characteristic curve, sensitivity, specificity, positive predictive value, and negative predictive value. The study will also estimate biopsy avoidance and missed clinically significant prostate cancer rates and explore multivariable models combining PET, MRI, and clinical variables. Participants should not expect direct clinical benefit, and the research PET result will not alter biopsy decisions or other standard care.

Study Type

Interventional

Enrollment (Estimated)

130

Phase

  • Not Applicable

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 Locations

  • United States
    • Arizona
      • Avondale, Arizona, United States, 85392
      • Chandler, Arizona, United States, 85224
      • Mesa, Arizona, United States, 85206
      • Phoenix, Arizona, United States, 85004
      • Scottsdale, Arizona, United States, 85254
      • Surprise, Arizona, United States, 85374
        • SimonMed Imaging - Surprise Stadium Village
        • 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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Male

Description

Inclusion Criteria:

  • Male, age 18 years or older
  • PI-RADS 3 lesion diagnosed by multiparametric MRI within the past 4 weeks
  • Clinical indication for prostate biopsy
  • Undergoing targeted biopsy and systematic biopsy as part of the routine clinical pathway
  • Able to provide written informed consent

Exclusion Criteria:

  • Prior diagnosis or treatment of prostate cancer
  • PI-RADS 4 or 5 lesion
  • Negative MRI, defined as PI-RADS 1 or 2
  • Contraindication to PSMA PET or prostate biopsy
  • Contraindication to both MRI and CT
  • Any medical condition that may interfere with study procedures

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
Intervention / Treatment
Experimental: POSLUMA PET Diagnostic Imaging

Participants undergo one research-only POSLUMA PET/MRI or PET/CT before targeted and systematic prostate biopsy.
Diagnostic test: PET Imaging with Flotufolastat F 18

Participants undergo research-only PSMA PET/MRI or PET/CT using POSLUMA (flotufolastat F 18) before clinically indicated prostate biopsy. POSLUMA is administered intravenously at 296 MBq (8 mCi), with PET imaging beginning approximately 60 minutes after administration. PET imaging findings are compared with histopathology from targeted and systematic prostate biopsy.

Other Names:
  • 18F-rhPSMA-7.3
  • POSLUMA

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diagnostic accuracy of POSLUMA PET for clinically significant prostate cancer
Time Frame: From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan

Lesion-level area under the receiver operating characteristic curve for POSLUMA PET metrics, including SUVmax and PRIMARY score, using biopsy histopathology and clinically significant prostate cancer defined as Gleason score 7 or higher as the reference standard.
From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Sensitivity of POSLUMA PET
Time Frame: From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan

Lesion-level sensitivity for detecting clinically significant prostate cancer using biopsy histopathology as the reference standard.
From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan
Specificity of POSLUMA PET
Time Frame: From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan

Lesion-level specificity for detecting clinically significant prostate cancer using biopsy histopathology as the reference standard.
From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan
Positive predictive value of POSLUMA PET
Time Frame: From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan

Positive predictive value for detecting clinically significant prostate cancer using biopsy histopathology as the reference standard.
From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan
Negative predictive value of POSLUMA PET
Time Frame: From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan

Negative predictive value for detecting clinically significant prostate cancer using biopsy histopathology as the reference standard.
From research PET imaging through histopathology review, up to approximately 6 weeks after the PET scan
Potential biopsy avoidance rate
Time Frame: At completion of biopsy histopathology review, up to approximately 6 weeks after the PET scan

Percentage of participants with low PSMA uptake who would be classified as potentially able to avoid biopsy under the study's exploratory imaging criteria.
At completion of biopsy histopathology review, up to approximately 6 weeks after the PET scan
Missed clinically significant prostate cancer rate
Time Frame: At completion of biopsy histopathology review, up to approximately 6 weeks after the PET scan

Proportion of clinically significant prostate cancer cases associated with low PSMA uptake under the study's exploratory imaging criteria.
At completion of biopsy histopathology review, up to approximately 6 weeks after the PET scan
Performance of a multivariable diagnostic model
Time Frame: After completion of imaging, biopsy, and histopathology data collection, through December 2028

Model performance when combining PSMA PET metrics with clinical and imaging variables such as PSA, PSA density, free-to-total PSA ratio, ADC, lesion volume, and other protocol-specified variables.
After completion of imaging, biopsy, and histopathology data collection, through December 2028

Collaborators and Investigators

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

Sponsor

SimonMed Imaging

Collaborators

Blue Earth Diagnostics

Investigators

  • Principal Investigator: Howard John Simon, MD, SimonMed Imaging

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 (Estimated)

December 1, 2026

Primary Completion (Estimated)

December 1, 2028

Study Completion (Estimated)

December 1, 2028

Study Registration Dates

First Submitted

October 29, 2026

First Submitted That Met QC Criteria

October 29, 2026

First Posted (Actual)

November 4, 2026

Study Record Updates

Last Update Posted (Actual)

November 4, 2026

Last Update Submitted That Met QC Criteria

October 29, 2026

Last Verified

October 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TUNIRB000379

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

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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