Four-in-One Antibodies Have Superior Cancer Inhibitory Activity against EGFR, HER2, HER3, and VEGF through Disruption of HER/MET Crosstalk

The anti-HER receptor antibodies cetuximab, trastuzumab, and pertuzumab are used widely in clinic to treat metastatic cancer. However, activation of the extensive crosstalk among the HER receptors as well as other RTKs, particularly HER-MET crosstalk, has emerged as a likely source of drug resistance. In this study, we developed two new types of tetra-specific antibodies that recognize EGFR, HER2, HER3, and VEGF. These tetra-specific antibodies, termed FL518 (four-in-one antibody) and CRTB6 (tetra-specific, tetravalent antibody), not only inhibited signaling mediated by these receptors in vitro and in vivo but unexpectedly also disrupted HER-MET crosstalk. When compared with two-in-one antibodies and a series of bispecific antibodies in multiple tumor models, FL518 and CRTB6 were more broadly efficacious. We further showed that tetra-specific antibodies were far more effective than bispecific antibodies in inhibiting the growth of anti-HER-resistant cancer cells, which exhibited elevated levels of MET activation both in vitro and in vivo. Overall, our results establish a new principle to achieve combined HER inhibition and limit drug resistance using a single antibody. (C) 2014 AACR.