Prospective Exploratory Study of FAPi PET/CT in Prostate Cancer With Histopathology Validation

Study Overview
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Brief Summary
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This exploratory study investigates how a new imaging technique called FAPI PET/CT can determine where and to which degree the FAPI tracer (68Ga-FAPi-46) accumulates in normal and cancer tissues in patients with prostate cancer. Because some cancers take up 68Ga-FAPi-46 it can be seen with PET. FAP stands for Fibroblast Activation Protein. FAP is produced by cells that surround tumors. The function of FAP is not well understood but imaging studies have shown that FAP can be detected with FAPI PET/CT. Imaging FAP with FAPI PET/CT may in the future provide additional information about various cancers including prostate cancer.

Detailed Description
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PRIMARY OBJECTIVE: I. To define the biodistribution of gallium 68Ga-FAPi-46 in normal and cancer tissues of patients with prostate cancer. SECONDARY OBJECTIVES: I. To evaluate whether 68Ga-FAPi-46 and gallium Ga 68-labeled PSMA-11 (68Ga-PSMA-11) accumulation observed by positron emission tomography (PET) correlates with the amount of fibroblast activation protein (FAP) and prostate specific membrane antigen (PSMA) in excised cancer tissue, respectively. II. To assess the 68Ga-FAPI-46 biodistribution correlation with 68Ga-PSMA-11. OUTLINE: Patients receive 68Ga-FAPi-46 intravenously (IV) and undergo PET/computed tomography (CT) imaging over 20-50 minutes.

Official Title
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PET Biodistribution Study of 68Ga-FAPI-46 in Patients With Prostate Cancer: A Prospective Exploratory Biodistribution Study With Histopathology Validation

Conditions
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Metastatic Malignant Neoplasm in the Prostate Gland, Prostate Carcinoma, Recurrent Prostate Carcinoma

Intervention / Treatment
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* Procedure: Computed Tomography
* Other: Gallium Ga 68 FAPi-46
* Procedure: Positron Emission Tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who underwent a 68Ga-PSMA-11 PET/CT scan within 3 months of enrollment Patients who are scheduled to undergo surgical excision or biopsy of a prostate cancer primary, recurrent or metastatic lesion Patients can provide written informed consent Patients are able to remain still for duration of imaging procedure (up to one hour) Exclusion Criteria: Patients with any new prostate therapy between the PSMA PET/CT and the FAP inhibitor (FAPI) PET/CT

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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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Basic Science (68Ga-FAPi-46 PET/CT)<br>Patients receive 68Ga-FAPi-46 IV and undergo PET/CT imaging over 20-50 minutes. | Procedure: Computed Tomography<br>* Undergo PET/CT imaging<br>* Other names: tomography;Other: Gallium Ga 68 FAPi-46<br>* Given IV<br>* Other names: Gallium-68-FAPi-46;Procedure: Positron Emission Tomography<br>* Undergo PET/CT imaging<br>* Other names: proton magnetic resonance spectroscopic imaging;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To define and document the biodistribution of gallium 68Ga-FAPi-46 in normal and cancer tissues of patients with prostate cancer | To quantify tumor tissue and normal background organs positron emission tomography (PET) tracer uptake by semi-quantitative analysis (unit/metrics = standardized uptake values [SUV], SUVmean and SUVmax. | 60 minutes after tracer injection | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To evaluate whether 68Ga-FAPi-46 accumulation observed by PET correlates with the amount of fibroblast activation protein (FAP) assessed by immunohistochemistry (IHC) in excised cancer tissue | 68Ga-FAPi-46 tumor SUVs will be correlated with FAP expression from surgically resected tumors. IHC will be scored with a semi-quantitative scoring system that accounts for staining intensity (0-2, where 0 is negative, 1 is weak, 2 is strong and eq. stands for equivocal). Correlations will be sought using least square regression analysis. | Up to date of surgery (range 1-60 days) | 
| To assess the 68Ga-FAPI-46 biodistribution correlation with 68Ga-PSMA-11 PET imaging | The 68Ga-PSMA-11 and 68Ga-FAPI-46 tracer biodistribution will be described by mean and maximum standardized uptake values (SUVmean and SUVmax) and tested for correlation. | 60 minutes after tracer injection |