A pilot study of the safety, efficacy, and effects on functional imaging of the combination of cG250 and sunitinib in patients (pts) with advanced renal cell carcinoma (RCC).

TPS142 Background: cG250 is an IgG1 kappa chimeric monoclonal antibody that binds to G250 (CAIX/MN), a heat-sensitive transmembrane cell-surface antigen homologous to carbonic anhydrase. CAIX/MN is present on more than 85% of RCC but expression in normal tissues is restricted to the gastric epithelium, biliary ducts, and some pancreatic acini. Previous studies have demonstrated excellent tumor targeting properties and safe administration either as cold antibody or labelled with various radioisotopes. A phase I multiple dose study completed at our site showed that cG250 is safe, has a long half-life and targets RCC effectively. We hypothesized that combination of cG250 and sunitinib would induce beneficial clinical effects by targeting complementary signalling pathways and that sunitinib’s acute effects on tumor vasculature would influence cG250 biodistribution, tumor metabolism and tumor blood flow. This ongoing study examines the safety and tolerability of coadministering cG250 with sunitinib in pts with...