This phase II trial studies how well a short course of androgen deprivation therapy (ADT) with relugolix works in increasing expression of prostate-specific membrane antigen (PSMA) and improving diagnostic imaging with PSMA positron emission tomography (PET)/computed tomography (CT) in patients with high risk or very high risk prostate cancer. PSMA PET/CT has become the standard of care in imaging for high-risk prostate cancer. However, a limitation of PSMA PET/CT is its ability to detect cancer that has spread to the lymph nodes. PSMA is a protein that is usually found on the surface of normal prostate cells but is found in higher amounts on prostate tumor cells. Studies have shown that expression of PSMA is regulated by androgens (male reproductive hormones). Relugolix binds to gonadotropin-releasing hormone receptors in the pituitary gland, which blocks the pituitary gland from making the hormones follicle-stimulating hormone and luteinizing hormone. This causes the testicles to stop making testosterone. Relugolix may stop the growth of tumor cells that need testosterone to grow. PSMA PET/CT is an imaging procedure that is used to help find prostate tumor cells in the body. For this procedure, a cell-targeting molecule linked to a radioactive substance (flotufolastat F 18 in this trial) is injected into the body and travels through the blood. It attaches to PSMA that is found on the surface of prostate tumor cells. PET/CT scanners detect high concentrations of the radioactive molecule and shows where the prostate tumor cells are in the body. Giving a short course of ADT with relugolix may increase PSMA expression to detect smaller areas of prostate cancer that were not previously detected.
PRIMARY OBJECTIVE: I. Comparison of maximum standard uptake value (SUVmax) and SUVmean values of the dominate primary prostate lesion between pre and post androgen deprivation therapy (ADT) imaging using flotufolastat F-18 gallium (POSLUMA \[flotufolastat F 18\]) PET/CT. SECONDARY OBJECTIVES: I. Evaluate and compare the lymph node sensitivity between pre and post ADT imaging using POSLUMA (flotufolastat F 18) PET/CT. II. Comparison of lymph node prostate-specific membrane antigen (PSMA) avidity between pre and post ADT imaging using POSLUMA (flotufolastat F 18) PET/CT. OUTLINE: Patients are randomized to 1 of 3 arms. ARM A: Patients receive flotufolastat F 18 and undergo PET/CT on day 0. Patients then receive relugolix orally (PO) once daily (QD) on days 1-5 in the absence of disease progression or unacceptable toxicity. Patients also receive flotufolastat F 18 and undergo PET/CT on day 5. Patients then undergo robotic radical prostatectomy with pelvic lymph node dissection within 90 days of 2nd flotufolastat F 18 PET/CT scan. In addition, patients undergo collection of blood samples throughout the study. ARM B: Patients receive flotufolastat F 18 and undergo PET/CT on day 0. Patients then receive relugolix PO QD on days 1-10 in the absence of disease progression or unacceptable toxicity. Patients also receive flotufolastat F 18 and undergo PET/CT on day 10. Patients then undergo robotic radical prostatectomy with pelvic lymph node dissection within 90 days of 2nd flotufolastat F 18 PET/CT scan. In addition, patients undergo collection of blood samples throughout the study. ARM C: Patients receive flotufolastat F 18 and undergo PET/CT on day 0. Patients then receive relugolix PO QD on days 1-15 in the absence of disease progression or unacceptable toxicity. Patients also receive flotufolastat F 18 and undergo PET/CT on day 15. Patients then undergo robotic radical prostatectomy with pelvic lymph node dissection within 90 days of 2nd flotufolastat F 18 PET/CT scan. In addition, patients undergo collection of blood samples throughout the study.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
30
Undergo collection of blood samples
Undergo PET/CT
Given flotufolastat F 18
Undergo robotic assisted radical prostatectomy
Undergo pelvic lymph node dissection
Undergo PET/CT
Given PO
Mayo Clinic in Arizona
Scottsdale, Arizona, United States
RECRUITINGMaximum standard uptake value (SUVmax) for pre and post androgen deprivation therapy (ADT) prostate-specific antigen (PSMA) positron emission tomography (PET)
Will be compared in all patients (pooled across randomization groups). We will explore differences between 5, 10 and 15 days since ADT initiation as hypothesis-generating, but the study will not be powered to detect differences between these groups.
Time frame: Day 0 up to day 15
Mean standard uptake value (SUVmean) for pre and post ADT PSMA PET
Will be compared in all patients (pooled across randomization groups). We will explore differences between 5, 10 and 15 days since ADT initiation as hypothesis-generating, but the study will not be powered to detect differences between these groups
Time frame: Day 0 up to day 15
Lymph node sensitivity of the pre and post ADT PSMA PET with surgical pathology as standard of truth
Accuracy of imaging results (pre/post) for identifying either pelvic nodal or distant metastatic disease will be evaluated versus pathology result (standard of care). The reference standard regarding the presence of pelvic nodal or distant metastases will be determined by histopathologic findings.
Time frame: Day 0 up to day 15
Lymph node PSMA avidity between pre and post ADT PSMA using flotufolastat F 18 PET/computed tomography (CT)
Accuracy of imaging results (pre/post) for identifying either pelvic nodal or distant metastatic disease will be evaluated versus pathology result (standard of care).
Time frame: Day 0 up to day 15
Incidence of adverse events (AEs)
Assessed using National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Version 5.0..The maximum grade for each type of AE will be recorded for each patient.
Time frame: Up to 90 days of 2nd PSMA PET/CT
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