Margetuximab-cmkb, a HER2/neu receptor antagonist, is a chimeric Fc-engineered IgG1 kappa monoclonal antibody. It binds to the extracellular domain of the human epidermal growth factor receptor 2 protein (HER2). Upon binding to HER2-expressing tumor cells, margetuximab-cmkb inhibits tumor cell proliferation, reduces shedding of the HER2 extracellular domain and mediates antibody-dependent cellular cytotoxicity (ADCC).