Digital PET/CT Using [Ga-68]PSMA for Characterization of Prostate Lesions

Study Overview
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Brief Summary
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The purpose of this study is to evaluate a radioactive diagnostic study drug, which is called Gallium-68 Prostate Specific Membrane Antigen ([Ga-68]PSMA) for characterization of prostate abnormalities.

Detailed Description
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Individuals with clinical suspicion of prostate cancer and without prior prostate biopsy are offered abbreviated bi-parametric prostate MRI. As Standard of Care (SOC), MRIs will be examined and scored for likelihood for malignancy using the PI-RADS version 2.1 criteria. Those with PI-RADS 3, 4 or 5 lesions or those with PI-RADS 1 or 2 lesions with clinical suspicion for prostate cancer based on serum PSA level, family history or clinical examination (positive digital rectal examination) will be included on study. Only those receiving care at University Hospitals Cleveland Medical Center will be included into the study. This study is to evaluate ([Ga-68]PSMA) for characterization of prostate abnormalities. For imaging, an FDA approved imaging technology, digital Positron Emission Tomography (PET/CT) will be used. The study team would like to know if digital PET/CT using [Ga-68]PSMA provides accurate information whether or not a participant has prostate cancer and if there is potential spread of the disease within the body. [Ga-68]PSMA is an investigational (experimental) drug that works by binding to Prostate Specific Membrane Antigen (PSA), which is overexpressed in prostate cancer. [Ga-68]PSMA is experimental because it is not approved by the Food and Drug Administration (FDA). However, FDA approval has been obtained for this study protocol by an Investigational New Drug (IND) application.

Official Title
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Digital PET/CT Using [Ga-68]PSMA for Characterization of Prostate Lesions

Conditions
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Prostate Cancer

Intervention / Treatment
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* Drug: [Ga-68]PSMA
* Device: PET/CT imaging


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who have a clinical suspicion of prostate cancer defined by PI-RADS 3, 4 or 5 lesions detected on MRI as well as patients with negative prostate MRI or those with PI-RADS 1 or 2 lesions if they have continued suspicion for prostate cancer. Patients who cannot undergo MRI imaging but have a clinical suspicion for prostate cancer based on serum PSA level, family history or clinical examination (positive digital rectal examination) can also be included. Able to tolerate PET/CT scans Informed consent must be given and signed Exclusion Criteria: Anti-cancer treatment (chemotherapy and/or radiation therapy) within the last 2 weeks Known allergy against Ga-68 PSMA Prior prostate biopsy within the last 2 weeks

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Digital PET/CT using [Ga-68]PSMA<br>Following prostate Standard of Care MRI, eligible participants will receive a single injection of [Ga-68]PSMA followed by digital PET/CT imaging approximately 60 minutes later. PET/CT takes approximately 30-35 minutes, where the participant would lay still on a scanner table. | Drug: [Ga-68]PSMA<br>* The injectable activity will be a maximum of 210 MBq (6.0 mCi) [Ga-68]PSMA at the time of injection and is administered to subjects by intravenous injection.<br>Device: PET/CT imaging<br>* PET/CT imaging procedure<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| True positive rate | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by true-positive rate. The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| False positive rate | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by false-positive rate. The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| True negative rate | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by true negative rate. The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| False negative negative rate | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by false negative rate. The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| Sensitivity | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by sensitivity. The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| Specificity | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by specificity. The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| Positive predictive value (PPV) | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by (PPV). The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| Negative predictive value (NPV) | Diagnostic performance of digital PET/CT using [Ga-68]PSMA for characterization of prostate lesions, as measured by (NPV). The uptake of [Ga-68]PSMA within the prostate gland will be visually assessed and compared to surrounding tracer uptake within the prostate gland. The majority of participants will subsequently undergo prostate biopsy as part of routine clinical work-up. Subsequent histopathology will be used as the reference standard. If participants do not undergo prostate biopsy, participant follow-up (PSA level, prostate imaging, or later biopsy) will be used as reference standard | During scan, up to 35 minutes | 
| Proportion of prostate lesions determined to be cancer determined by [Ga-68]PSMA compared to histopathology | Quantitative data collected from PET biomarker ([Ga-68]PSMA) uptake will be used to analyze prostate lesions for differentiation between benign prostate changes and prostate cancer. Differentiation prostate lesion by PET biomarker will be compared to histology reference standard. | During scan, up to 35 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determination of prostate lesion aggressiveness using Gleason scores | Uptake of ([Ga-68]PSMA) will be compared with the Gleason score, which is a grading system used to determine the aggressiveness of prostate cancer. Scores range from 2 to 10, with higher scores indicating worse outcomes (more likely that the cancer will grow and metastasize) | During scan, up to 35 minutes | 
| Determination of prostate lesion aggressiveness using prostate grading system scores | Uptake of ([Ga-68]PSMA) wil be compared with the prostate grading system score, which is an extension of the current Gleason grading scale for determining the stage and aggressiveness of prostate cancer. This system is designed to provide a simplified and more accurate grading stratification system than the current Gleason Score. Scores range from 1 to 5, with higher scores indicating worse outcomes | During scan, up to 35 minutes | 
| Average pre-test PSA level | Average pre-test PSA level will be measured and reported. Ability of digital PET/CT using [Ga-68]PSMA uptake to identify malignant prostate lesions will be explored by plotting PSA levels against diagnostic performance of PET/CT using [Ga-68]PSMA, with histopathology serving as the reference standard. | During scan, up to 35 minutes | 
| Proportion of metastatic lesions identified by digital PET/CT using [Ga-68]PSMA compared to reference | Focally increased [Ga-68]PSMA uptake within the torso PET images will be compared with standard of care clinical imaging to verify the presence of metastatic lesions. In addition, patient follow up and histopathology will be used as reference if available. | During scan, up to 35 minutes |