Catumaxomab is a 150 kDa hybrid IgG2 like molecule targeting epithelial cell adhesion molecule (EpCAM), a tumor antigen and CD3 on the T cells in contrast to Blinatumomab, which is a 55 kDa bispecific T cell engager (BiTE) targeting CD19 on the cancer cell and CD3 on the T cell. Here, CD19 is linked to cancer.