Definition

An antibody-drug conjugate (ADC) composed of a monoclonal antibody directed against the tumor-associated antigen (TAA) carcinoembryonic antigen (CEA; carcinoembryonic antigen-related cell adhesion molecule 5; CEACAM5; CD66e) and conjugated to a cytotoxic camptothecin-based payload, with potential antineoplastic and immune checkpoint inhibitory activities. Upon administration of anti-CEACAM5 ADC SGN-CEACAM5C, the monoclonal antibody moiety targets and binds to CEA expressed on tumor cells. Upon binding and internalization, the payload is released. The camptothecin payload inhibits DNA topoisomerase I activity, thereby inhibiting DNA replication and resulting in cell cycle arrest and tumor cell apoptosis. This inhibits the proliferation of CEA-expressing tumor cells. CEA, a member of the CEA family of proteins that plays a key role in cell migration, cell invasion, and cell adhesion, is overexpressed by a variety of cancer cell types. Its expression is limited in normal. healthy, adult tissues, but is overexpressed in various cancers.