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

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.

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.