Phase 3 multicenter randomized trial of PSMA PET/CT prior to definitive radiation therapy for unfavorable intermediate-risk or high-risk prostate cancer [PSMA dRT]: study protocol.

Definitive radiation therapy (dRT) is an effective initial treatment of intermediate-risk (IR) and high-risk (HR) prostate cancer (PCa). PSMA PET/CT is superior to standard of care imaging (CT, MRI, bone scan) for detecting regional and distant metastatic PCa.

PSMA PET/CT thus has the potential to guide patient selection and the planning for dRT and improve patient outcomes.

This is a multicenter randomized phase 3 trial (NCT04457245). We will randomize 312 patients to proceed with standard dRT (control Arm, n = 150), or undergo a PSMA PET/CT scan at the study site (both 18F-DCFPyL and 68Ga-PSMA-11 can be used) prior to dRT planning (intervention arm, n = 162). dRT will be performed at the treating radiation oncologist facility. In the control arm, dRT will be performed as routinely planned. In the intervention arm, the treating radiation oncologist can incorporate PSMA PET/CT findings into the RT planning. Androgen deprivation therapy (ADT) is administered per discretion of the treating radiation oncologist and may be modified as a result of the PSMA PET/CT results. We assume that approximately 8% of subjects randomized to the PSMA PET arm will be found to have M1 disease and thus will be more appropriate candidates for long-term systemic or multimodal therapy, rather than curative intent dRT. PET M1 patients will thus not be included in the primary endpoint analysis. The primary endpoint is the success rate of patients with unfavorable IR and HR PCa after standard dRT versus PSMA PET-based dRT. Secondary Endpoints (whole cohort) include progression free survival (PFS), metastasis-free survival after initiation of RT, overall survival (OS), % of change in initial treatment intent and Safety.

This is the first randomized phase 3 prospective trial designed to determine whether PSMA PET/CT molecular imaging can improve outcomes in patients with PCa who receive dRT. In this trial the incorporation of PSMA PET/CT may improve the success rate of curative intent radiotherapy in two ways: to optimize patient selection as a biomarker and to personalizes the radiotherapy plan.

UCLA IND#147591 ○ Submission: 02.27.2020 ○ Safe-to-proceed letter issued by FDA: 04.01.2020 UCLA IRB #20-000378 ClinicalTrials.gov Identifier NCT04457245 . Date of Registry: 07.07.2020. Essen EudraCT 2020-003526-23.

BMC cancer. 2021 May 07*** epublish ***

Jeremie Calais, Shaojun Zhu, Nader Hirmas, Matthias Eiber, Boris Hadaschik, Martin Stuschke, Ken Herrmann, Johannes Czernin, Amar U Kishan, Nicholas G Nickols, David Elashoff, Wolfgang P Fendler

Ahmanson Translational Theranostics Division, Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Peter Norton Medical Building, 200 Medical Plaza, Suite B-114-51, Los Angeles, CA, 90095-7370, USA. ., Ahmanson Translational Theranostics Division, Department of Molecular & Medical Pharmacology, David Geffen School of Medicine, University of California, Peter Norton Medical Building, 200 Medical Plaza, Suite B-114-51, Los Angeles, CA, 90095-7370, USA., Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium (DKTK)-University Hospital Essen, Hufelandstraße 55, 45131, Essen, Germany., Department of Nuclear Medicine, Klinikum rechts der Isar, Technical University Munich, Munich, Germany., Department of Urology, University of Duisburg-Essen and German Cancer Consortium (DKTK)-University Hospital Essen, Essen, Germany., Department of Radiotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany., Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, USA., Institute of Urologic Oncology, University of California Los Angeles, Los Angeles, CA, USA.

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