Fusion Pharmaceuticals Inc., a clinical-stage oncology company focused on developing next-generation radiopharmaceuticals as precision medicines, 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. Data were presented at the Society of Nuclear Medicine and Molecular Imaging (SNMMI) 2022 Annual Meeting in a presentation titled “Impact of Pre-Administration of Anti-IGF-1R Antibody FPI-1175 on the Dosimetry, Tumor Uptake, and Pharmacokinetics of the IGF-1R Targeted Theranostic Imaging Agent [111In]-FPI-1547 in Patients with Solid Tumors”.
“Pre-administration of cold antibody has the potential to increase the therapeutic index of radiopharmaceuticals through multiple avenues, including adjusting the pharmacokinetics to increase drug circulation and drive increased binding to tumor targets, saturating natural sinks for antibodies and blocking endogenous antibody binding,” said Chief Executive Officer John Valliant, Ph.D. “The positive trends observed in tumor lesion uptake when cold antibody is pre-administered validate our ongoing evaluation of additional cohorts using this dosing regimen in the Phase 1 trial of FPI-1434.”
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.