Abstract
Malignant ascites is frequently found with various solid tumors, and no established treatment options exist, apart from symptomatic paracentesis. Catumaxomab, a trifunctional bispecific monoclonal antibody, has two binding specificities directed to epithelial cell adhesion molecule (EpCAM) and the T cell antigen CD3. With its Fc-fragment, catumaxomab additionally binds accessory cells, including dendritic cells, macrophages, and natural killer cells. The trifunctional approach thus leads to a major histocompatibility complex-unrestricted but specific killing of epithelial tumor cells without need for preactivation or external costimulation. Because EpCAM is expressed in most solid tumors, but not in tissue of mesothelial origin, intraperitoneal treatment with catumaxomab is tumor-specific. Intraperitoneal treatment with catumaxomab resulted in a significant prolongation of puncture-free survival in patients with malignant ascites due to epithelial cancer. Catumaxomab has been approved in Europe for the intraperitoneal treatment of malignant ascites in patients with EpCAM-positive epithelial tumors where standard therapy is not available or no longer feasible.