A recombinant, fully human, bispecific antibody neutralizes the biological activities mediated by both vascular...

Vascular endothelial growth factors (VEGF) and their receptors (VEGFR) have been implicated to play important roles in tumor-associated angiogenesis and lymphangiogenesis, and hence in tumor growth and metastasis. We previously produced a number of fully human antibodies directed against VEGF receptor 2 (VEGFR2) and VEGF receptor 3 (VEGFR3) and showed that these antibodies are capable of inhibiting growth factor (VEGF and VEGF-C)-induced receptor activation, migration, and proliferation of human endothelial cells. In this report, we constructed and produced a bispecific antibody, a diabody, using the variable domain genes of two neutralizing antibodies, IMC-1121 to VEGFR2 and hF4-3C5 to VEGFR3. The diabody binds to both VEGFR2 and VEGFR3 in a dose-dependent manner, and blocks interaction between VEGF/VEGFR2, VEGF-C/VEGFR2, and VEGF-C/VEGFR3. In cell-based assays, the diabody neutralized both VEGF and VEGF-C-stimulated activation of VEGFR2, VEGFR3, and p44/p42 mitogen-activated protein kinase in endothelial cells. Furthermore, the diabody was able to inhibit both VEGF and VEGF-C-induced migration of endothelial cells. Taken together, our results suggest that a dual blockade of both VEGFR2 and VEGFR3 simultaneously may represent a more potent approach to effective cancer therapy.