Carcinoembryonic antigen (CEA) (CEA)

Carcinoembryonic antigen (CEA), also known as CEACAM5, is a cell surface glycoprotein and a member of the immunoglobulin superfamily that primarily functions as a cell adhesion molecule. While its expression in healthy adults is largely restricted to the mucosal surface of the gastrointestinal tract, it is highly overexpressed in various epithelial malignancies, including colorectal, pancreatic, and gastric cancers [15]. The "DOTAM-binding arm of CEA-directed bispecific antibody" refers to a specialized component of a pretargeted radioimmunotherapy (PRIT) system, such as the PRIT-0213 (RO7198427) platform developed by Roche and Orano Med [7, 9]. This system utilizes a bispecific antibody with one arm targeting CEA on tumor cells and a second arm—the DOTAM-binding arm—designed with femtomolar affinity for a metal-chelate complex, specifically Lead-DOTAM (Pb-DOTAM) [5, 7]. The therapeutic strategy involves a sequential process where the bispecific antibody first localizes to the tumor, followed by the administration of a radiolabeled 212Pb-DOTAM payload [10]. This approach allows for the precise delivery of high-energy alpha-particle radiation to the tumor while ensuring rapid systemic clearance of the small-molecule radioligand, thereby minimizing off-target toxicity to the bone marrow and kidneys [9, 13].

Other names

CEACAM5Carcinoembryonic antigen-related cell adhesion molecule 5CD66eCarcinoembryonic antigen

Pretargeted radioimmunotherapy (PRIT) utilizing a bispecific antibody to localize at CEA-expressing tumor cells and subsequently capture a radiolabeled Lead-DOTAM (Pb-DOTAM) complex via a high-affinity binding arm.