PET/CT Characterization of Treatment Resistance

February 16, 2026 updated by: University of Wisconsin, Madison

PET/CT Characterization of Treatment Resistance of AR-targeted Therapies in mCRPC

This study will use different types of medical imaging to assess how lesions from advanced prostate cancer become resistant to second-generation AR-targeted therapy, and how the different types of imaging compare in that assessment. Participants in this study have advanced prostate cancer and are either scheduled to start a second-generation androgen receptor (AR) targeted therapy (such as enzalutamide, abiraterone, or apalutamide) or are already being treated with one. Participants can expect to be in the study for at least 9 months, and up to 2 years.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

There are two groups, or cohorts, in this study. Participants are assigned to Cohort A if they have advanced prostate cancer and are scheduled to start a second-generation AR-targeted therapy (such as enzalutamide, abiraterone, darolutamide, or apalutamide) or PSMA directed radiotherapy (e.g. Lu177-PSMA radio-ligand therapy. Participants are assigned to Cohort B if they have advanced prostate cancer, are already on a second-generation AR-targeted therapy, and have shown an increase in their PSA (prostate-specific antigen) levels.

There are two medical imaging scans that will be done for research purposes in this study. One is called 18F-fluorodeoxyglucose positron emission tomography (FDG PET) and the other is prostate-specific membrane antigen positron emission tomography (PSMA PET). These scans are done simultaneously with computed tomography (CT) scanning. Participants will be scheduled to have 6 scans, 3 FDG PET/CT scans and 3 PSMA PET/CT scans.

Study Type

Interventional

Enrollment (Estimated)

25

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
    • Wisconsin
      • Madison, Wisconsin, United States, 53705
        • Recruiting
        • University of Wisconsin
        • Contact:
        • Principal Investigator:
          • Christos Kyriakopoulos, MD

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

Study Population

Men with prostate cancer being treated by the UWCCC Genitourinary Oncology Program.

Description

Inclusion Criteria:

  • Histologically proven adenocarcinoma of the prostate.
  • At least 1 radiographic metastases as seen on conventional CT imaging or bone scan
  • Progressive prostate cancer as evident by at least two separate increase in PSA over nadir, and absolute PSA value at least 2 ng/ml (INTRINSIC RESISTANCE COHORT, ARSI patients ONLY)
  • Patients must be candidate for a second-generation androgen receptor (AR) inhibitor (e.g. enzalutamide, abiraterone, darolutamide, apalutamide), or Lu177-PSMA radioligand therapy (INTRINSIC RESISTANCE COHORT ONLY)
  • Men of age >18 years.
  • Patients must be able to comply with all study procedures, including having both the ability and willingness to lie flat for ≥ 30 minutes during imaging
  • Patients must be informed of the exploratory nature of the study and its potential risks, and must sign IRB-approved consent form indicating such understanding.
  • Life-expectancy at least 12 months
  • Patients currently receiving a second-generation androgen receptor (AR) inhibitor (e.g. enzalutamide, abiraterone, darolutamide, apalutamide) and must have had 1) PSA decline on treatment and 2) now have PSA increase over nadir while still on treatment (patients must be registered within 12 weeks of first documented PSA increase) (ACQUIRED RESISTANCE COHORT ONLY)

Exclusion Criteria:

  • Must not have uncontrolled diabetes (fasting blood sugar > 200 mg/dL or inability to safely hold diabetes medication or fast 6 hours prior to FDG PET scan)
  • Prior treatment with second-generation AR inhibitor for prostate cancer in the metastatic disease setting (prior second-generation AR inhibitor in the neoadjuvant or adjuvant setting is permitted unless patient developed progression while on treatment) (INTRINSIC RESISTANCE COHORT, AR-INHIBITOR GROUP ONLY)
  • Pain or clinical symptoms from metastatic prostate cancer requiring opioid analgesics
  • Known neuro-endocrine prostate cancer
  • Prior radioisotope therapy for castration-resistant prostate cancer
  • To avoid the possibility of unintended coercion, vulnerable populations such as incarcerated subjects, subjects unable to provide their own informed consent and non-English speaking patients will not be considered

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: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: Acquired Resistance Cohort (Cohort B)
Participants are assigned to Cohort B if they have advanced prostate cancer, are already on a second-generation AR-targeted therapy, and have shown an increase in their PSA (prostate-specific antigen) levels.
Diagnostic test: F-fluorodeoxyglucose positron emission tomography (FDG PET)
Imaging scan
Diagnostic test: prostate-specific membrane antigen positron emission tomography (PSMA PET)
Imaging scan
Other: Intrinsic Resistance Cohort (Cohort A)
Participants assigned to Cohort A have advanced prostate cancer and are scheduled to start a second-generation AR-targeted (such as enzalutamide, abiraterone, darolutamide, or apalutamide) or PSMA directed (e.g. Lu177-PSMA) therapies .
Diagnostic test: F-fluorodeoxyglucose positron emission tomography (FDG PET)
Imaging scan
Diagnostic test: prostate-specific membrane antigen positron emission tomography (PSMA PET)
Imaging scan

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Characterize intrinsic resistance based on FDG and PSMA PET through change in individual lesion update levels.
Time Frame: Baseline to 12 weeks
Changes in individual lesion update levels (ΔiSUVtotal) will be calculated. SUVtotal is a metric of activity, for which less activity is better.
Baseline to 12 weeks
Characterize change in intrinsic resistance based on FDG and PSMA PET.
Time Frame: Baseline to 12 weeks
Changes in individual lesion update levels (ΔiSUVtotal) will be calculated. SUVtotal is a metric of activity, for which a decrease in activity is better.
Baseline to 12 weeks
Characterize change in intrinsic resistance based on FDG and PSMA PET.
Time Frame: 12 weeks to 36 weeks
Changes in individual lesion update levels (ΔiSUVtotal) will be calculated. SUVtotal is a metric of activity, for which a decrease in activity is better.
12 weeks to 36 weeks
Characterize change in intrinsic resistance based on FDG and PSMA PET.
Time Frame: Baseline to 36 weeks
Changes in individual lesion update levels (ΔiSUVtotal) will be calculated. SUVtotal is a metric of activity, for which a decrease in activity is better.
Baseline to 36 weeks
Characterize acquired resistance at the time of progression
Time Frame: Baseline to 36 weeks
Percentage and absolute changes in individual lesion update levels (ΔiSUVtotal) will be calculated.
Baseline to 36 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Correlate amount of intrinsic resistance on FDG and PSMA PET to predict time to PSA progression
Time Frame: Baseline to 36 weeks
Analysis will be conducted to evaluate whether changes in lesion uptake values predict time to PSA progression. PSA progression will be 25% increase and >2 ng/mL above PSA nadir
Baseline to 36 weeks
Correlate amount of intrinsic resistance on FDG and PSMA PET to predict time duration on treatment
Time Frame: Up to 36 weeks
Analysis will be conducted to evaluate whether changes in lesion uptake values predict duration of treatment. Duration of treatment will be defined as the time from treatment start, to treatment discontinuation (and reason for discontinuation) using PCWG3 criteria.
Up to 36 weeks
Correlate amount of intrinsic resistance on FDG and PSMA PET to predict time to radiographic progression
Time Frame: Baseline to 36 weeks
Analysis will be conducted to evaluate whether changes in lesion uptake values predict time to radiographic progression. Time to radiographic progression will be defined as the number of days to confirmed radiographic progression using Prostate Cancer WorkingGroup 3 (PCWG3) criteria.
Baseline to 36 weeks

Collaborators and Investigators

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

Sponsor

University of Wisconsin, Madison

Investigators

  • Principal Investigator: Glenn Liu, MD, University of Wisconsin, Madison
  • Principal Investigator: Robert Jeraj, PhD, University of Wisconsin, Madison

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)

March 6, 2023

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

September 1, 2026

Study Registration Dates

First Submitted

December 6, 2022

First Submitted That Met QC Criteria

December 6, 2022

First Posted (Actual)

December 12, 2022

Study Record Updates

Last Update Posted (Actual)

February 17, 2026

Last Update Submitted That Met QC Criteria

February 16, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2022-0910 (Other Identifier: UW Madison)
  • A534260 (Other Identifier: UW Madison)
  • SMPH/MEDICINE/HEM-ONC (Other Identifier: UW Madison)
  • NCI-2022-09580 (Registry Identifier: NCI)
  • Protocol Version 11/15/2025 (Other Identifier: UW Madison)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

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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