Catumaxomab: a bispecific trifunctional antibody.

ABSTRACT

The trifunctional bispecific monoclonal antibody catumaxomab has two binding specificities directed at epithelial cell adhesion molecule (EpCAM) and the T-cell antigen CD3. With its Fc-fragment, catumaxomab additionally binds accessory cells such as dendritic cells, macrophages and natural killer cells. The trifunctional approach thus leads to unrestricted but specific killing of epithelial tumor cells by major histocompatibility complex without the need for preactivation or external costimulation. The tumor-associated antigen EpCAM is strongly expressed in carcinomas of various origins including colon, rectum, ovarian, gastric, esophagus, lung, pancreas, breast and head and neck. Expression of EpCAM is often associated with an unfavorable prognosis in patients with breast cancer. Catumaxomab has been approved in Europe for the intraperitoneal treatment of malignant ascites in patients with EpCAM-positive epithelial tumors when standard therapy is not available or is no longer feasible. Basic preclinical and clinical findings with different routes of catumaxomab administration in various indications are summarized and discussed in this review.