Comparative biodistribution analysis across four different

Area of Science:

• Nuclear medicine
• Radiopharmaceutical science
• Pharmacokinetics

Background:

• Understanding monoclonal antibody biodistribution in healthy tissues is crucial for clinical drug development.
• Positron emission tomography (PET) molecular imaging provides valuable data on antibody behavior.
• Previous studies focused on single antibodies, lacking comparative analysis.

Purpose of the Study:

• To compare the biodistribution of four different 89Zr-labeled monoclonal antibodies in healthy human tissues.
• To establish a harmonized approach for analyzing and comparing 89Zr-tracer imaging data.
• To provide a foundation for a comprehensive molecular imaging data warehouse.

Main Methods:

• Retrospective analysis of 89Zr-labeled lumretuzumab, MMOT0530A, bevacizumab, and trastuzumab distribution.
• Application of a recently published harmonization protocol for 89Zr-tracers.
• Utilized a specific delineation protocol for healthy tissue analysis.

Main Results:

• The four antibodies exhibited largely similar biodistribution patterns on day 4 post-injection.
• Highest tracer concentrations were observed in the liver, spleen, kidneys, and intestines.
• Significant accumulation was noted in circulation (approx. 33%) and liver (up to 15%), with notable contribution from adipose tissue (5-7%, up to 19%).

Conclusions:

• Similar biodistribution is likely due to comparable molecular structures, binding affinities, and metabolic pathways of the antibodies.
• These findings support the creation of an online data warehouse for molecular imaging, facilitating knowledge exchange.
• The data can potentially aid in drug development decisions regarding antibody distribution.