This phase I trial studies the impact of monosodium glutamate (MSG) on 68GA-PSMA-11 PET/CT in decreasing the salivary glands uptake in patients with prostate cancer. Prostate specific membrane antigen (PSMA) is a molecule that is overexpressed by the prostate cancer cells. 68GA-PSMA-11 is an imaging radioactive drug that can target this molecule in tissues for imaging and therapy of prostate cancer. Food substances, such as monosodium glutamate, may reduce salivary gland uptake of 68GA-PSMA-11. Ultimately, giving MSG may reduce potential harm and injury to the salivary glands in patients with prostate cancer treated with PSMA-targeted molecular radiotherapy.
PRIMARY OBJECTIVE: I. To determine the effect of monosodium glutamate (MSG) administration (glutamate supplementation) on the salivary gland uptake of gallium Ga 68-labeled PSMA-11 (68Ga-PSMA-11). SECONDARY OBJECTIVES: I. To determine the effect of MSG administration on renal 68Ga-PSMA-11 uptake. II. To determine the effect of MSG administration on tumor 68Ga-PSMA-11 uptake. III. To determine if 68GA-PSMA-11 is excreted in the saliva. IV. Safety of MSG administration both oral ingestion and oral-salivary stimulation. OUTLINE: Patients are randomized to 1 of 2 arms. Arm I: Patients receive gallium Ga 68-labeled PSMA-11 intravenously (IV) and undergo a positron emission tomography (PET)/computed tomography (CT) scan on day 1. Within 2 weeks (days 2-14), patients receive MSG orally (PO) over 10 minutes and receive a second dose of gallium Ga 68-labeled PSMA-11 IV, followed by a second PET/CT scan. Patients also undergo collection of saliva at 0, 30, and 60 minutes after gallium Ga 68-labeled PSMA-11 injection and 90 minutes after PET/CT. Arm II: Patients receive gallium Ga 68-labeled PSMA-11 IV and undergo a PET/CT scan on day 1. Within 2 weeks (days 2-14), patients receive a second dose of gallium Ga 68-labeled PSMA-11 IV immediately followed by MSG applied in the mouth over 30 seconds every 10 minutes for a total of 6 times, and then undergo a second PET/CT scan. Patients also undergo collection of saliva at 0, 30, and 60 minutes after gallium Ga 68-labeled PSMA-11 injection and 90 minutes after PET/CT.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
SINGLE
Enrollment
14
Undergo collection of saliva
Undergo PET/CT
Given IV
Given PO
Undergo PET/CT
UCLA / Jonsson Comprehensive Cancer Center
Los Angeles, California, United States
Salivary gland uptake of gallium Ga 68-labeled PSMA-11 (68Ga-PSMA-11)
Standard uptakes values (SUV) values (maximum SUV \[SUVmax\] and SUVmean) in all assessable salivary glands will be measured with a spherical volume-of-interest with and without the administration of monosodium glutamate (MSG) interventions. SUVmax/salivary gland will be calculated and a mean SUVmax/patient will be generated. The aim is to show a 2-fold reduction of the salivary gland 68Ga-PSMA-11 uptake after MSG administration. Paired T-test will be used to determine statistical significance per salivary gland and per patient.
Time frame: 2 measurements within 2 to 14 days maximum (on positron emission tomography [PET]1 and PET2)
Renal 68Ga-PSMA-11 uptake
SUVmax and SUVmean in the kidneys will be measured with a spherical volume-of-interest with and without the administration of MSG interventions. SUVmax/kidneys will be calculated and a mean SUVmax/patient will be generated. Paired T-test will be used to determine statistical significance per salivary gland and per patient.
Time frame: 2 measurements within 2 to 14 days maximum (on PET1 and PET2)
Tumor 68Ga-PSMA-11 uptake
SUVmax and SUVmean in the visible tumor lesions will be measured with a spherical volume-of-interest with and without the administration of MSG interventions. SUVmax/tumor lesions will be calculated and a mean SUVmax/patient will be generated. Paired T-test will be used to determine statistical significance per salivary gland and per patient.
Time frame: 2 measurements within 2 to 14 days maximum (on PET1 and PET2)
Saliva radioactivity concentration
Saliva radioactivity concentration will be compared with and without saliva stimuli.
Time frame: 2 measurements within 2 to 14 days maximum (on PET1 and PET2)
Incidence of adverse events of MSG administration
Time frame: Up to 6 months
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