Phase 2b Imaging Study of RAD101 in Participants With Suspected Recurrent Brain Metastases

This is an open-label, single dose, single arm, multicenter Phase 2b study to establish the imaging performance of RAD101 PET in participants who are ≥ 18 years of age and with suspected recurrent brain metastases from solid tumors. Approximately 30 participants will be enrolled in the study. To avoid overrepresentation of a specific tumor type, a maximum of 15 participants per tumor type will be enrolled: lung, breast, colon, kidney, or melanoma. The study consists of a 4-week Screening Period, a 3-day Imaging and Safety Follow-Up Period, and a Data Collection Period of up to 6 months. Participant eligibility will be determined during the Screening Period and eligible participants will be enrolled in the study. All participants will have a post-SRS (stereotactic radiosurgery)/ SRT (stereotactic radiotherapy) MRI (otherwise CT) performed as their SoC within 8 weeks before Day 1. For enrolled participants, the screening MRI (otherwise CT) images will be collected and submitted for central imaging review. On Day 1, the enrolled participants will receive a single dose of the investigational medicinal product (IMP), RAD101, at a target dose of 370 Megabecquerel (MBq) (10 millicurie (mCi)) ± 10% through a slow intravenous (IV) bolus injection over a maximum of 30 seconds, followed by a saline flush. Participants will then proceed with a whole brain PET scan at 60 ± 10 min post-dose. A high-resolution MRI will be performed in joint acquisition with PET or separately on the same day, or on the day prior or the day following RAD101 administration. For applicable study sites where PK samples will be collected, whole body PET scans will be performed, blood samples will be drawn, and urine will be collected throughout the scanning period. Safety assessments, such as physical examination, vital signs, Electrocardiogram (ECG), and laboratory tests, will be conducted on Day 1 before RAD101 administration. Vital signs and ECG will be repeated at the end of infusion (for participants undergoing PK assessments) 35 ± 5 min following RAD101 administration on Day 1. A phone follow-up will be performed on Day 3 (+ 1 day). Participants will have follow-up (longitudinal) MRI (otherwise CT) scans (longitudinal imaging) and/ or a biopsy according to their SoC. If a biopsy is performed as part of their SoC during follow-up, the location of the biopsied lesion(s) and results of histopathology assessments on the lesion(s) will be collected. The longitudinal image results will be collected for central reading until a SoC biopsy is performed and the histopathology results are available, or up to 6 months following RAD101 administration, whichever comes first. The longitudinal image results, and details of the biopsy if performed as part of SoC (i.e., location and histopathology results), will be collected during the 6- month Data Collection Period. To limit the number of participants being exposed to a dose-ranging study, the minimum effective dose (MBq) of RAD101 will be assessed on a subset of 6 to 10 participants using images obtained by simulated count reduction. The duration of study participation for each participant is approximately 211 days (7 months), including 28 days of the Screening Period, 3 days of the Imaging and Safety Follow-Up Period, and up to 180 days of the Data Collection Period. The duration of the entire study is planned to be approximately 15 months.