Another bispecific agent is the AMG211, a T-cell engager antibody construct used in phase I trials for targeting carcinoembryonic antigen (CEA) (Kebenko et al., 2018; Pishvaian et al., 2016), an established therapeutic target in a number of solid tumors, including breast cancer (Tang et al., 2016, Wang et al., 2017). Here, CEACAM5 is linked to breast cancer.