Fusion Pharmaceuticals Inc. announced the presentation of imaging data from the "cold antibody sub-study" evaluating pre-administration of cold antibody (naked antibody without the isotope) prior to administration of the imaging agent (antibody with the isotope) in the Phase 1 study of FPI-1434 for the treatment of solid tumors expressing IGF-1R. The cold antibody sub-study was conducted concurrently with the dose escalation portion of the Phase 1 study of FPI-1434 for the treatment of solid tumors. The sub-study was designed to determine the safety, tolerability, and effect of administration of varying doses of FPI-1175, the naked antibody without the isotope, or "cold antibody", on the biodistribution, dosimetry and tumor uptake of [111In]-FPI-1547, the investigational imaging agent.

Imaging data from the study demonstrate a favorable gain in [111In]-FPI-1547 tumor lesion uptake versus normal tissue when FPI-1175 was pre-administered and compared to dosing with FPI-1547 alone. Importantly, sites of improved tumor lesion uptake were independent of anatomic location of disease and included bone, lung, liver, and lymph nodes. Administration of FPI-1547 with and without pre-administration of FPI-1175 was safe without any drug-related Serious Adverse Events or Dose Limiting Toxicities.

Pre-administration of FPI-1175 at 0.5 mg/kg is currently being evaluated with increasing dose levels of FPI-1434 in the ongoing Phase 1 study.