188Re-Labelled Anti-EGFr Humanised Monoclonal Antibody h-R3 forradioimmunotherapy

摘要

The aim of the present work was to label monoclonal antibody h-R3 with 188Re and toassess its animal biodistribution. Materials and methods: 2-mercaptoethanol was used as a reducingagent. The amount of sodium glucoheptonate, ascorbic acid and stannous fluoride were varied toachieve optimum labelling yield. Challenge against 300-fold molar excess of L-cysteine was made toassess the stability of the tracer. Animal biodistribution study was performed at 3 and 24 h afterintravenous administration of 188Re-h-R3 and 99mTc-h-R3 through tale vein of male Wistar rats. A trialwas performed by administering into the post-operative cavity through an indwelling catheter a singledose 188Re-h-R3. Five patients were included. SPECT and planar images as well as multiple blood andurine samples were collected up to 24 h after administration of 3 mg of Mab labelled with 370 MBq188Re. Absorbed dose were estimated using the MIRD methodology at organ and voxel level. Results:Radiochemical purity of 188Re-h-R3 was 98.0±0.4%. There was not found significant differencebetween stability of 188Re-h-R3 and 99mTc-h-R3 against cysteine challenge up to 24 h. Biodistributionstudy showed high radiopharmaceutical uptake in kidneys and small intestine. Urinary excretion wassimilar for the antibody labelled with 188Re as well as 99mTc. Conclusions: Proposed procedureallowed the efficient and stable labelling of h-R3 with 188Re.