Exploratory PK and Imaging Study of PSMA-Targeted Trillium Compounds and PTI-122 in Metastatic Prostate Cancer

Inclusion Criteria: * Adult males with metastatic prostate cancer * ECOG performance score 0-2 * Stable androgen deprivation or other hormone therapy (30 days) or therapy planned but not yet initiated * PSMA PET scan between 3 and 28 days prior to radiotracer injection with at least 2 PSMA positive lesions and either: 1. One soft tissue lesion measuring ≥ 15 mm in the longest diameter with SUVmax lesion ≥ SUVmean normal liver, OR 2. Two bone lesions measuring ≥ 15 mm in the longest diameter with SUVmax lesion ≥ 2 x SUVmax normal liver * Able to understand and adhere to study requirements, and voluntarily give informed consent Exclusion Criteria: * No other malignancy undergoing treatment * No PSMA-targeted therapy ongoing * Inability or unwillingness to undergo SPECT/CT imaging * Serum creatinine \> 1.5 mg/dL or creatinine clearance ≤50 mL/min by Cockcroft-Gault estimation * Concurrent participation in the active treatment phase of another clinical trial of investigational medicinal product(s) * Significant intercurrent illness, treatment-related toxicity, or psychiatric illness/social situation that could place the subject at undue risk during study participation, significantly alter study outcomes, or affect subject compliance with study requirements for dosing and evaluation, as determined by the investigator