Purpose: Radioimmunotherapy may improve the outcome of hepatocellular carcinoma (HCC) patients by delivering targeted radiation to liver lesion tissue while relatively sparing nontarget tissues. This study was designed to observe the biodistribution, localization and imaging characteristics of 131I -labeled Metuximab in 24 patients with HCC to determine the diagnostic and therapeutic potential of this antibody.
Methods: Twenty-four HCC patients were randomly divided into three groups to receive 18.5, 27.75 and 37 MBq/kg of 131I-labeled Metuximab per kilogram of body weight, respectively. 99mTc-sodium phytate was administered intravenously and the single photon emission computed tomography (SPECT) scanning was performed. After 48 h, 131I -labeled Metuximab was injected by hepatic artery intubation, and SPECT scan performed at 7 d. The percentage of absorbed 131I (%ID) and the time-dependent 131I tumor:nontumor tissue (T/NT) ratios were calculated at 12, 48, 96 and 192 h after injection.
Results: The positive Imaging result of MAb scanning in 24 patients showed that the iodine 131 conjugated to Metuximab was apparently accumulated more in hepatoma. Biodistribution studies of 131I-Metuximab in trial I demonstrated that the comparable % ID uptake in tumor (with a T/NT ratio at 12, 48, 96 and 192 h) to that in such normal organs, as thyroid, heart, lung, spleen and intestines were all more than one. The optimal imaging time for the highest T/NT ratio in liver was at 192 h.
Conclusion: 131I-labeled Metuximab could deliver relatively selective radiation to tumor tissues and may have potential efficacy in relieving hepatocellular carcinoma.