Multicenter Randomized Trial of 68Ga-PSMA-11 PET/CT Based SRT After Radical Prostatectomy (PSMA SRT)

Phase III Randomized Multicenter Trial of 68Ga-PSMA-11 PET/CT Molecular Imaging for Prostate Cancer Salvage Radiotherapy Planning [PSMA-SRT]

This phase III trial studies how well Gallium Ga 68-labeled PSMA-11 (68Ga-PSMA-11) positron emission tomography (PET)/computed tomography (CT) works in diagnosing participants with prostate cancer that has come back after surgery. 68Ga-PSMA-11 are taken up by cancer cells. Diagnostic procedures, such as PET/CT scans, may help find and diagnose prostate cancer and find out how far the disease has spread. Giving 68Ga-PSMA-11 with PET/CT may help doctors plan better for salvage radiation therapy in participants with recurrent prostate cancer.

PRIMARY OBJECTIVE: I. Success rate of salvage radiation therapy (SRT) measured as biochemical progression-free survival after initiation of SRT. SECONDARY OBJECTIVES: I. Sub-group analysis of the primary endpoint (success rate of SRT) within the subgroup with baseline PSA ≥ 0.5 ng/ml II. 5-year biochemical progression-free survival rate (from date of randomization). III. Metastasis free survival. IV. Initiation of additional salvage therapy after completion of SRT. V. Change in initial treatment intent. OUTLINE: Participants are randomized to 1 of 2 arms. ARM I: Participants receive standard of care SRT. ARM II: Participants receive 68Ga-PSMA-11 intravenously (IV) and 50-100 minutes later undergo whole-body (skull base to mid-thighs) PET/CT. Participants then undergo SRT per the discretion of the treating radiation oncologist. After conclusion of PET/CT, participants are followed up periodically for up to 5 years.

Participants receive 68Ga-PSMA-11 IV and 50-100 minutes later undergo whole-body (skull base to mid-thighs) PET/CT. Participants then undergo SRT per the discretion of the treating radiation oncologist.

(68)Ga labeled Glu-NH-CO-NH-Lys(Ahx)-HBED-CC, (68)Ga-labeled Glu-urea-Lys(Ahx)-HBED-CC, (68)Ga-PSMA Ligand Glu-urea-Lys(Ahx)-HBED-CC, (68)Gallium-PSMA Ligand Glu-urea-Lys(Ahx)-HBED-CC, (68Ga)Glu-urea-Lys(Ahx)-HBED-CC, 68Ga-DKFZ-PSMA-11, 68Ga-HBED-CC-PSMA, 68Ga-labeled Glu-NH-CO-NH-Lys(Ahx)-HBED-CC, 68Ga-PSMA, 68Ga-PSMA-11, 68Ga-PSMA-HBED-CC, [68Ga] Prostate-specific Membrane Antigen 11, [68Ga]GaPSMA-11, Ga PSMA, Ga-68 labeled DKFZ-PSMA-11, Ga-68 labeled PSMA-11, Gallium Ga 68 PSMA-11, Gallium-68 PSMA, Gallium-68 PSMA Ligand Glu-urea-Lys(Ahx)-HBED-CC, GaPSMA, PSMA-HBED-CC GA-68

Medical Imaging, Positron Emission Tomography, PET, PET Scan, Positron Emission Tomography Scan, Positron-Emission Tomography, proton magnetic resonance spectroscopic imaging

Will be measured as biochemical progression-free survival after initiation of SRT. Will use a log rank test to compare progression free survival time between the two randomized treatment arms.

Will utilize Cox-proportional hazards regression models. These models will include terms for treatment as well as appropriate clinical/demographic covariates (e.g., androgen deprivation therapy [ADT], pelvic lymph node radiation therapy [LN RT], prostate specific antigen [PSA] doubling time, Gleason grade, T stage, age, etc). Residual analyses will be performed to evaluate the proportional hazards assumptions of the Cox model. As a sensitivity analysis, we will also consider survival models that can account for competing risks (ex. death from other causes).

Will utilize Cox-proportional hazards regression models. These models will include terms for treatment as well as appropriate clinical/demographic covariates (e.g., ADT, pelvic LN RT, PSA doubling time, Gleason grade, T stage, age, etc). Residual analyses will be performed to evaluate the proportional hazards assumptions of the Cox model. As a sensitivity analysis, we will also consider survival models that can account for competing risks (ex. death from other causes).

Will utilize Cox-proportional hazards regression models. These models will include terms for treatment as well as appropriate clinical/demographic covariates (e.g., ADT, pelvic LN RT, PSA doubling time, Gleason grade, T stage, age, etc). Residual analyses will be performed to evaluate the proportional hazards assumptions of the Cox model. As a sensitivity analysis, we will also consider survival models that can account for competing risks (ex. death from other causes).

Will utilize Cox-proportional hazards regression models. These models will include terms for treatment as well as appropriate clinical/demographic covariates (e.g., ADT, pelvic LN RT, PSA doubling time, Gleason grade, T stage, age, etc). Residual analyses will be performed to evaluate the proportional hazards assumptions of the Cox model. As a sensitivity analysis, we will also consider survival models that can account for competing risks (ex. death from other causes).

Inclusion Criteria: Histopathology proven prostate cancer. Planned SRT for recurrence after primary prostatectomy. Prostate-specific antigen (PSA) >= 0.1 ng/ml at time of enrollment. Willingness to undergo radiotherapy. Treating radiation oncologist intends to incorporate 68Ga-PSMA-11 PET/CT findings into the radiotherapy plan if patient undergoes 68Ga-PSMA-11 PET/CT. Exclusion Criteria: Extra-pelvic metastasis on any imaging or biopsy. Androgen deprivation therapy (ADT) within 3 months before 68Ga-PSMA-11 PET/CT. Contraindications to radiotherapy (including active inflammatory bowel disease). Concurrent systemic therapy for prostate cancer with investigational agents.

Calais J, Armstrong WR, Kishan AU, Booker KM, Hope TA, Fendler WP, Elashoff D, Nickols NG, Czernin J. Update from PSMA-SRT Trial NCT03582774: A Randomized Phase 3 Imaging Trial of Prostate-specific Membrane Antigen Positron Emission Tomography for Salvage Radiation Therapy for Prostate Cancer Recurrence Powered for Clinical Outcome. Eur Urol Focus. 2021 Mar;7(2):238-240. doi: 10.1016/j.euf.2020.12.009. Epub 2020 Dec 30.

Calais J, Czernin J, Fendler WP, Elashoff D, Nickols NG. Randomized prospective phase III trial of 68Ga-PSMA-11 PET/CT molecular imaging for prostate cancer salvage radiotherapy planning [PSMA-SRT]. BMC Cancer. 2019 Jan 7;19(1):18. doi: 10.1186/s12885-018-5200-1. Erratum In: BMC Cancer. 2019 Jan 21;19(1):97.