PRIMARY OBJECTIVE:~I. To determine the safety and tolerability of vudalimab (XmAb20717) in combination with standard of care treatment in subjects with metastatic castration sensitive prostate cancer (mCSPC) as assessed by frequency and intensity of adverse events.~SECONDARY OBJECTIVE:~I. To assess the preliminary antitumor activity of XmAb20717 with standard of care treatment.~TERTIARY/EXPLORATORY OBJECTIVE:~I. To identify factors that may be indicative of response to XmAb20717 in combination with standard of care treatments.~OUTLINE: Patients are assigned to 1 of 3 cohorts.~COHORT A: Patients receive vudalimab intravenously (IV) on days 1 and 15 plus abiraterone orally (PO) once daily (QD) of 4-week cycles on study. Patients also undergo prostate-specific membrane antigen (PSMA) positron emission tomography (PET) and fludeoxyglucose (FDG) PET scans during screening. Patients also undergo computed tomography (CT) and/or magnetic resonance imaging (MRI) scans, bone scans, and blood sample collection throughout the study.~COHORT B: Patients receive vudalimab IV on days 1 and 15 plus enzalutamide PO QD of 4-week cycles on study. Patients also undergo PSMA PET and FDG PET scans during screening. Patients also undergo CT and/or MRI scans, bone scans, and blood sample collection throughout the study.~COHORT C: Patients receive vudalimab IV on days 1 and 15, docetaxel IV on days 1 and 22 plus abiraterone PO QD of 6-week cycles on study. Patients also undergo PSMA PET and FDG PET scans during screening. Patients also undergo CT and/or MRI scans, bone scans, and blood sample collection throughout the study.
This phase I trial tests the safety and effectiveness of vudalimab in combination with standard of care treatment abiraterone, enzalutamide, or abiraterone plus docetaxel in treating patients with castration sensitive prostate cancer that has spread to other places in the body (metastatic). Immunotherapy with monoclonal antibodies, such as vudalimab, may help the body's immune system attack the cancer, and may interfere with the ability of tumor cells to grow and spread. Adding vudalimab to standard of care treatments may be effective in treating metastatic castration sensitive prostate cancer.