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 orlocally advanced, inoperable, or recurrent. Solid tumors indications may includePDAC, CRC, NED prostate cancer, gastric cancer, SCCHN, and Ewing sarcoma.

• Disease that has progressed despite prior treatment, and for which additionaleffective standard therapy is not available or is contraindicated, not tolerable, orthe 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 byimaging 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 thisstudy

• Anti-cancer therapy, such as chemotherapy, immunotherapy, hormonal therapy, targetedtherapy, or investigational agents within certain amount of time prior toadministration 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 studyrequirements

• 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