NCT05647564 · University of Wisconsin, Madison
PET/CT Characterization of Treatment Resistance
What this study is about
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.
View original scientific description
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.
Interventions
DIAGNOSTIC_TEST
F-fluorodeoxyglucose positron emission tomography (FDG PET)
Imaging scan
DIAGNOSTIC_TEST
prostate-specific membrane antigen positron emission tomography (PSMA PET)
Imaging scan
Primary outcome measures
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.
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.
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.
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.
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.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
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
Where
- Madison, Wisconsin
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Feb 17, 2026 · Source of record for eligibility and locations