292 A preclinical pharmacokinetic/pharmacodynamic study for anti-PDGF receptor alpha antibody 3G3 in a human glioblastoma xenograft model

Radioimmunodetection (RAID) is more sensitive and specific than conventional diagnostic methods. In this study, a monoclonal antibody against cervical carcinoma antigen, MAb Cx-99, was labeled with 111Indium (111In). This immunoconjugate was intravenously injected into athymic nude mice bearing cervical squamous cell carcinoma (SCC) xenografts. The tissue distribution study showed that the xenograft tumor had higher binding activity than most other tissues after 48 h from injection, demonstrated by localization ratio of tumor or tissues (c.p.m./g) against blood (c.p.m./g). However, this localization ratio was also high in the liver, spleen and kidney. The imaging study by immunoscintigraphy also showed that the tumor and liver were distinct from other background tissues 2 days after injection. This preliminary study showed that 111In-labeled MAb Cx-99 may have potential for RAID of cervical cancer, especially for tumors in the pelvis.