Acquired Resistance to a MET Antibody Can Be Overcome by the MET Antibody Mixture Sym015.

Failure of clinical trials due to development of resistance to MET-targeting therapeutic agents is an emerging problem. Mechanisms of acquired resistance to MET tyrosine kinase inhibitors are well described, whereas characterization of mechanisms of resistance toward MET-targeting antibodies is limited. This study investigated mechanisms underlying resistance to two antibody therapeutics currently in clinical development: an analogue of the MET-targeting antibody emibetuzumab and Sym015, a mixture of two antibodies targeting nonoverlapping epitopes of MET.

Sym015: A Highly Efficacious Antibody Mixture against -Amplified Tumors.

Activation of the receptor tyrosine kinase MET is associated with poor clinical outcome in certain cancers. To target MET more effectively, we developed an antagonistic antibody mixture, Sym015, consisting of two humanized mAbs directed against nonoverlapping epitopes of MET. We screened a large panel of well-annotated human cancer cell lines and identified a subset with highly elevated MET expression.