Evaluation of Fapi-pet in Prostate Cancer.

Study Overview
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Brief Summary
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The investigators explore the biodistribution of FAPI-PET expression in primary high-risk prostate cancer in men undergoing RALP and eLND and in men with metastatic PCa about to start next generation antiandrogen.

Detailed Description
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This is an exploratory cohort study comprised of men with clinically localized or locally advanced high-risk prostate cancer (GG 3-5, cT2-cT3, Nx, M0) managed by RALP and eLND and men with metastatic (mHSPC or mCRPC) prostate cancer scheduled to start NHT along clinical care pathway (e.g., apalutamide, enzalutamide) at HUS Helsinki University Hospital and Helsinki University, Finland. Men identified along routine clinical care as candidates for the study will be asked to consent. Once consented, patients will undergo PSMA-PET imaging instead of conventional imaging (CT and bone scan) and experimental FAPI-PET imaging. Furthermore, biomarker samples will be obtained before and after treatment (surgery or novel antiandrogen) and surgical specimen will be processed for routine pathological evaluation and multiplex IHC studies. Serum samples will be tested for PCa biomarkers (e.g., PSA, NSE, CgA) and cfDNA. Urine will be processed and extracellular vesicles (exosomes) isolated and markers of reactive stroma will be sought for. Radical prostatectomy and novel hormonal treatment will be done according to current recommendations and guidelines in Finland. Postoperatively, patients will be followed with PSA every six months. Biochemical recurrence will be set at PSA of 0.2 ug/l or higher.

Official Title
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Evaluation of Fapi-pet in Prostate Cancer

Conditions
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Prostate Cancer

Intervention / Treatment
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* Procedure: Computed tomography


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men scheduled for radical prostatectomy Age over 18 years GG 3-5, cT2-cT3, Nx, M0 prostate cancer no contraindication to PSMA - or FAPI-PET willing to undergo study related procedures (imaging and laboratory tests) Men scheduled for novel antiandrogen Age over 18 years GG2-5, cT2-4, N0-1, M1 hormone sensitive or castration resistant prostate cancer Exclusion Criteria: Not willing or capable to undergo study related procedures

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 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
Interventional Model Description: Exploratory prospective cohort study.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: FAPI PET<br>Prospective single arm cohort | Procedure: Computed tomography<br>* Positron Emission Tomography<br>* Other names: 68-Ga-FAPI-4 PET/CT;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Positive predictive value on a lesion level | Positive predictive value of FAPI-PET on a lesion level using histopathology or confirmatory imaging as ground truth | through study completion, an average of 1 year | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Positive predictive value on a patient level | Positive predictive value of FAPI-PET on a patient level using histopathology or confirmatory imaging as ground truth | through study completion, an average of 1 year | 
| To assess the biodistribution of FAPI PET signal in comparison to PSMA-PET signal | To explore and compare the biodistribution and signal level of FAPI-PET and PSMA-PET | through study completion, an average of 1 year | 
| To assess the biodistribution of FAPI and PSMA PET signal in comparison to histology | To explore the biodistribution and signal level of FAP-PET and PSMA-PET in correlation to reference histology (lesion volume and grade in radical prostatectomy specimen and lymphadenectomy specimen) | through study completion, an average of 1 year | 
| To assess the biodistribution of FAPI and PSMA PET signal in comparison to immunohistochemistry | To explore the biodistribution and signal level of FAPI-PET and PSMA-PET in correlation to tissue protein levels of: FAP and PSMA Markers of reactive stroma and CAFs Neuregulin-1 Androgen receptor signalling pathway | through study completion, an average of 1 year | 
| To assess the biodistribution of FAPI and PSMA PET signal in comparison to biomarkers in wet samples | To correlate FAPI-PET and PSMA-PET biodistribution and signal level to: Postoperative serum biomarker levels (e.g., PSA, afos) cfDNA/RNA levels in peripheral blood Urinary exosome status for markers of reactive stroma Biochemical recurrence | through study completion, an average of 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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PET, PSMA, FAP, radical prostatectomy, novel antiandrogen, enzalutamide, apalutamide, FAPi, exosome