NCT03876912

The Effect of ADT on PSMA Expression in Metastatic Prostate Cancer

The Effect of Androgen Deprivation Therapy on the Expression of Prostate Specific Membrane Antigen (PSMA) Evaluated With 18F-PSMA PET/CT in Treatment naïve Metastatic Prostate Cancer Patients

• Status: Unknown
• Phase: N/A
• Study type: Interventional
• Enrollment: 35 (estimated)
• Sponsor: Turku University Hospital · Other Government
• Sex: Male
• Age: 40 Years – 85 Years
• Healthy volunteers: Not accepted

Summary

Thirty-five men with newly diagnosed, metastatic prostate cancer are scanned with 18F-PSMA 1007 PET/CT at baseline, 3 weeks after the initiation of GnRH-antagonist, at one year and at the time of castration resistant prostate cancer (CRPC). The aim of the study is to classify metastatic lesions into those with PSMA-flare and those without and determine their potential to progress during the follow-up until CRPC.

Detailed description

In metastatic prostate cancer androgen deprivation therapy (ADT) has been traditionally used as a first line approach. Based on histological studies, animal models and PSMA-PET imaging, it is known that administration of ADT increases prostate specific membrane antigen (PSMA) expression. Preliminary results of our previous prospective clinical trial (clinicaltrials.gov identifier: NCT03313726) with nine men demonstrated a heterogenous flare in PSMA expression 2-3 weeks after ADT, more evidently in bone metastases. Our hypothesis is that metastatic lesions having PSMA-flare respond differently to ADT and have different outcome than those without PSMA-flare. Therefore, the objective of the study is to demonstrate the PSMA-flare seen in bone lesions 3 weeks after ADT and then determine the potential predictive value of the phenomenon in the progression to castration resistant prostate cancer (CRPC). Thirty-five men with newly diagnosed, metastatic PC will undergo 18F-PSMA 1007 PET/CT before and 3 weeks after the initiation of sub-cutaneous injection of GnRH-antagonist (Degarelix, Firmagon®). A subgroup of 20 patients will receive an additional FDG PET/CT scan before ADT to investigate whether lesions with PSMA flare show a different metabolic behaviour on FDG PET. During the follow-up, 18F-PSMA 1007 PET/CT will be also performed once a year. Finally all patients will repeat 18F-PSMA 1007 PET/CT at the time of CRPC. In addition to imaging, PSA is measured, and blood drawn for androgen levels and biomarkers in three months interval.

Conditions

• Prostate Cancer

Interventions

Type	Name	Description
DRUG	GnRH antagonist	18F-PSMA 1007 PET/CT before, 3 weeks after ADT, at 1 year and at CRPC in 35 patients. 18F-FDG PET/CT in a subgroup of 20 patients before ADT.

Timeline

• Start date: 2019-03-01
• Primary completion: 2021-09-01
• Completion: 2023-03-01
• First posted: 2019-03-15
• Last updated: 2021-04-13

Locations

1 site across 1 country: Finland