A Study of [225Ac]-FPI-2059 in Adult Participants With Solid Tumours

Key Inclusion Criteria: Signed ICF prior to initiation of any study-specific procedures Histologically and/or cytologically confirmed solid tumor that is metastatic or locally advanced, inoperable, or recurrent. Solid tumors indications may include PDAC, CRC, NED prostate cancer, gastric cancer, SCCHN, and Ewing sarcoma. Disease that has progressed despite prior treatment, and for which additional effective standard therapy is not available or is contraindicated, not tolerable, or the patient refuses standard therapy Measurable disease per RECIST v.1.1 Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 Sufficient target expression in at least one measurable lesion as determined by imaging following injection of [111In]-FPI-2058 Adequate organ function Tumor tissue (either archival within the last 24 months or fresh biopsy) Key Exclusion Criteria: Previous treatment with any radiopharmaceutical Contraindications to or inability to perform the imaging procedures required in this study Anti-cancer therapy, such as chemotherapy, immunotherapy, hormonal therapy, targeted therapy, or investigational agents within certain amount of time prior to administration of the first dose of [111In]-FPI-2058 Radiation therapy (RT) within 28 days prior to the first dose of [111In]-FPI-2058 Patients with known CNS metastatic disease Concurrent severe and/or uncontrolled illness that would limit compliance with study requirements Known or suspected allergies or contraindication to the investigational treatment Received any type of vaccine within 30 days prior to the first dose of [111In]-FPI-2058