[18F]FTT Positron Emission Tomography for the Measurement of PARP Tumor Expression in Patients With Metastatic Breast Cancer

OUTLINE: Patients are assigned to 1 of 2 arms. Arm I: Patients receive \[18F\]FTT intravenously (IV) and undergo PET scan 60-75 minutes later on day 1 of initiating SOC PARP inhibitor ± ICI therapy and again at 12 weeks. At least 1-7 days later, patients undergo SOC FDG PET/computed tomography (CT) and follow up scans at 12 weeks and 6 months. Patients may also undergo tissue biopsy during screening and during follow up. Arm II: Patients receive \[18F\]FTT IV and undergo PET scan 60-75 minutes later on day 1 of initiating SOC PARP inhibitor ± ICI therapy. At least 1-7 days later, patients undergo SOC FDG PET/CT and follow up scans at 12 weeks and 6 months. Patients may also undergo tissue biopsy during screening. After initial \[18F\]FTT PET imaging, patients are followed-up to 6 months or until disease progression.