TY - JOUR
T1 - Quantitative PET of EGFR expression in xenograft-bearing mice using 64Cu-labeled cetuximab, a chimeric anti-EGFR monoclonal antibody
AU - Cai, Weibo
AU - Chen, Kai
AU - He, Lina
AU - Cao, Qizhen
AU - Koong, Albert
AU - Chen, Xiaoyuan
N1 - Funding Information:
Acknowledgements This project was financially supported by National Institute of Biomedical Imaging and Bioengineering (NIBIB) (R21 EB001785), National Cancer Institute (NCI) (R21 CA102123, P50 CA114747, U54 CA119367, and R24 CA93862), Department of Defense (DOD) (W81XWH-04-1-0697, W81XWH-06-1-0665, W81XWH-06-1-0042, and DAMD17-03-1-0143), and a Benedict Cassen Postdoctoral Fellowship from the Education and Research Foundation of the Society of Nuclear Medicine (to W.Cai).
PY - 2007/6/1
Y1 - 2007/6/1
N2 - Purpose: Cetuximab, a chimeric monoclonal antibody targeting epidermal growth factor receptor (EGFR) on the surface of cancer cells, was approved by the FDA to treat patients with metastatic colorectal cancer. It is currently also in advanced-stage development for the treatment of several other solid tumors. Here we report for the first time the quantitative positron emission tomography (PET) imaging of EGFR expression in xenograft-bearing mice using 64Cu-labeled cetuximab. Methods: We conjugated cetuximab with macrocyclic chelating agent 1,4,7,10-tetraazadodecane-N′,N″N, N‴-tetraacetic acid (DOTA), labeled with 64Cu, and tested the resulting 64Cu-DOTA-cetuximab in seven xenograft tumor models. The tracer uptake measured by PET was correlated with the EGFR expression quantified by western blotting. The estimated human dosimetry based on the PET data in Sprague-Dawley rats was also calculated. Results: MicroPET imaging showed that 64Cu-DOTA-cetuximab had increasing tumor activity accumulation over time in EGFR-positive tumors but relatively low uptake in EGFR-negative tumors at all times examined (<5%ID/g). There was a good correlation (R 2 = 0.80) between the tracer uptake (measured by PET) and the EGFR expression level (measured by western blotting). Human dosimetry estimation indicated that the tracer may be safely administered to human patients for tumor diagnosis, with the dose-limiting organ being the liver. Conclusion: The success of EGFR-positive tumor imaging using 64Cu-DOTA-cetuximab can be translated into the clinic to characterize the pharmacokinetics, to select the right population of patients for EGFR-targeted therapy, to monitor the therapeutic efficacy of anti-EGFR treatment, and to optimize the dosage of either cetuximab alone or cetuximab in combination with other therapeutic agents.
AB - Purpose: Cetuximab, a chimeric monoclonal antibody targeting epidermal growth factor receptor (EGFR) on the surface of cancer cells, was approved by the FDA to treat patients with metastatic colorectal cancer. It is currently also in advanced-stage development for the treatment of several other solid tumors. Here we report for the first time the quantitative positron emission tomography (PET) imaging of EGFR expression in xenograft-bearing mice using 64Cu-labeled cetuximab. Methods: We conjugated cetuximab with macrocyclic chelating agent 1,4,7,10-tetraazadodecane-N′,N″N, N‴-tetraacetic acid (DOTA), labeled with 64Cu, and tested the resulting 64Cu-DOTA-cetuximab in seven xenograft tumor models. The tracer uptake measured by PET was correlated with the EGFR expression quantified by western blotting. The estimated human dosimetry based on the PET data in Sprague-Dawley rats was also calculated. Results: MicroPET imaging showed that 64Cu-DOTA-cetuximab had increasing tumor activity accumulation over time in EGFR-positive tumors but relatively low uptake in EGFR-negative tumors at all times examined (<5%ID/g). There was a good correlation (R 2 = 0.80) between the tracer uptake (measured by PET) and the EGFR expression level (measured by western blotting). Human dosimetry estimation indicated that the tracer may be safely administered to human patients for tumor diagnosis, with the dose-limiting organ being the liver. Conclusion: The success of EGFR-positive tumor imaging using 64Cu-DOTA-cetuximab can be translated into the clinic to characterize the pharmacokinetics, to select the right population of patients for EGFR-targeted therapy, to monitor the therapeutic efficacy of anti-EGFR treatment, and to optimize the dosage of either cetuximab alone or cetuximab in combination with other therapeutic agents.
KW - Cetuximab
KW - Copper-64
KW - Epidermal growth factor receptor
KW - Micro-positron emission tomography
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U2 - 10.1007/s00259-006-0361-6
DO - 10.1007/s00259-006-0361-6
M3 - Article
C2 - 17262214
AN - SCOPUS:34249055896
SN - 1619-7070
VL - 34
SP - 850
EP - 858
JO - European Journal of Nuclear Medicine and Molecular Imaging
JF - European Journal of Nuclear Medicine and Molecular Imaging
IS - 6
ER -