Immuno-PET is a very powerful imaging technique to improve tumor detection because it combines high sensitivity and resolution of PET with specificity of a monoclonal antibody (mAb). Panitumumab, a fully humanized mAb is recently (2006) approved by FDA for the treatment of colorectal cancers. We anticipated that 89Zr labeled panitumumab would be an ideal imaging probe to quantify HER1-expression to guide therapy and dosing. Panitumumab was chemically conjugated with bifunctional chelate desferrioxamine (DFO) at well defined ratios (1:1-2) and subsequently labeled with 89Zr with very high radiochemical yield and purity. Biodistribution studies performed on non-tumor bearing mice showed minimal (1-4%ID/gm) organ uptake. Immuno-PET imaging studies of xenograft tumor bearing mice with very low, medium, and high HER1-expression levels at 24, 48, 72, 96, and 144 hours post injection showed a nice correlation between HER1-expression level and tumor uptake. Funded by NCI/NIH, Contract No. HHSN261200800001E

Immuno-PET with 89Zr labeled Panitumumab for the assessment of HER1-expression level in carcinomas

244th National Meeting (2012)

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