In-Labeled panitumumab, a fully human monoclonal antibody directed against the extracellular domain III of the epidermal growth factor receptor

Panitumumab is a fully human anti-epidermal factor receptor (EGFR) monoclonal antibody (mAb) that has been approved by the United States Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancers that express the EGFR and are unresponsive to chemotherapy (1). This mAb has a very high affinity for the extracellular domain III of the EGFR. The general characteristics of panitumumab have been described by Argiles et al. (2), and its mode of action has been illustrated by Dubois and Cohen (1). The fully human mAb has been reported to be well tolerated by individuals, slows disease progression, and improves the progression-free survival of patients (3). Therefore, [In]-labeled panitumumab ([In]-panitumumab) was evaluated for the noninvasive detection of EGFR-positive tumors in an effort to screen for patients who would benefit from radioimmunotherapy with this mAb after it was labeled with a suitable radionuclide (3). The In-labeled mAb was studied , and the biodistribution of [In]-panitumumab was investigated in athymic mice bearing xenograft tumors generated with A431, HT-29, LS-174T, SHAW (obtained from the National Cancer Institute), and SKOV-3 cell lines, respectively (3). In addition, gamma scintigraphic images were acquired from mice bearing xenograft tumors to confirm noninvasive visualization of the lesions.