177Lu-anti-PD-L1 sdAb in Metastatic Solid Tumors

This is a first in human, Phase 0/1, open-label study of 177Lu-RAD204 consisting of an Imaging Period with 177Lu-RAD204im (imaging dose) and a Treatment Period with 177Lu-RAD204tr (treatment dose) to determine the recommended dose(s) for future exploration of 177Lu-RAD204 in participants with PDL1+ advanced solid tumors. Screening Period: Screening Period of up to 4 weeks. Phase 0 (Imaging Period): Low dose (10mCi) of 177Lu-RAD204 administered on Imaging Day 1 with a follow-up period of up to 2 weeks to assess imaging, safety and dosimetry. The dose may be increased, if needed, to improve image quality. Phase 1 (treatment Period): 177Lu-RAD204tr dose escalation * Treatment Period with each cycle lasting 6 weeks. Extension of the planned dose intervals are possible following discussion and agreement between the Sponsor and Investigator. * Participants may be treated with multiple cycles, as long as they appear to derive clinical benefit as determined by the Investigator and provided there is adequate clinical safety and organ dosimetry data. * Dose Limiting Toxicity (DLT) observation period for 177Lu-RAD204tr is 6 weeks following the first injection of 177Lu-RAD204tr. * Should an alternative treatment schedule be explored, the DLT observation period for 177Lu-RAD204tr at that dose level will be the proposed cycle duration.