The contribution of catumaxomab in the treatment of malignant ascites in patients with ovarian cancer: a review of the literature

The approval of the first specific drug catumaxomab for the treatment of malignant ascites is the subject of this review. This trifunctional antibody is known to kill EpCAM-positive tumor cells and therefore attacks the primary cause of malignant ascites formation in the peritoneal cavity. Until today catumaxomab is the only EpCam-targeted antibody approved by the European Medicines Agency. Ovarian cancer is caused by epithelial tumors cells which overexpress epithelial cell adhesion molecule (EpCAM). The existing literature concerning the use of catumaxomab for the treatment of malignant ascites associated with ovarian cancer until today is reported in this article. It is very encouraging that different prospective studies from diverse scientific teams recently presented positive results concerning the efficacy and the safety of catumaxomab in the treatment of malignant ascites in patients with ovarian cancer. A case of a patient with ovarian cancer FIGO IIIc is also referred in this article. A complete remission and stable disease was found after 4 i.p. infusions of catumaxomab.

[Pathogenesis and management of refractory malignant ascites]

Malignant ascites are the cancer-associated accumulation of fluids in the peritoneal cavity. The neoplasms most frequently associated with ascites are ovarian, breast, colon, stomach and pancreas adenocarcinomas. Symptoms are abdominal distention, nausea, vomiting, anorexia, dyspnea and limbs oedemas. Several pathophysiological mechanisms might be implicated such as peritoneal carcinomatosis, lymphatic vessels' obstruction, portal hypertension or heart failure. Its diagnosis is most often performed in a context of already known neoplasia. Malignant ascites are associated with a pejorative evolution. Ascites which cannot be mobilized or show early recurrence and cannot be prevented by medical treatment are defined as refractory ascites. Therefore, management of refractory malignant ascites takes place in the context of palliative care and aims at improving the quality of life of these patients. This review lists the current data reported on the pathophysiology of malignant ascites and describes the present and future options for refractory malignant ascites management.

Bispecific Antibodies: Molecules That Enable Novel Therapeutic Strategies

Bispecific antibodies are unique in the sense that they can bind simultaneously two different antigens. This property enables the development of therapeutic strategies that are not possible with conventional monoclonal antibodies. The large panel of imaginative bispecific antibody formats that has been developed reflects the strong interest for these molecules. Although in many cases the manufacturing of clinical grade material remains challenging, several bispecific antibody formats are currently in clinical trials.

Frequent high-level expression of the immunotherapeutic target Ep-CAM in colon, stomach, prostate and lung cancers

Epithelial cell adhesion molecule (Ep-CAM; CD326) is used as a target by many immunotherapeutic approaches, but little data are available about Ep-CAM expression in major human malignancies with respect to level, frequency, tumour stage, grade, histologic tumour type and impact on survival. We analysed by immunohistochemical staining tissue microarrays with 4046 primary human carcinoma samples from colon, stomach, prostate and lung cancers for both frequency and intensity of Ep-CAM expression under highly standardised conditions. A total of 3360 samples were analysable. High-level Ep-CAM expression was observed in 97.7% (n=1186) of colon, 90.7% of gastric (n=473), and 87.2% of prostate cancers (n=414), and in 63.9% of lung cancers (n=1287). No detectable Ep-CAM staining was found with only 0.4% of colon, 2.5% of gastric, 1.9% of prostate cancers, and 13.5% of lung cancers. The only significant correlation of Ep-CAM expression with tumour grading was observed in colon cancer where high-level Ep-CAM expression on grade 3 tumours was down to 92.1% (P<0.0001). Adenosquamous and squamous carcinomas of the lung had a lower percentage of high-level Ep-CAM expression compared to adenocarcinomas with 35.4 and 53.6%, respectively, and with 45.5 and 17.3% of tumours being Ep-CAM negative. With the exception of moderately differentiated colon carcinoma, where patients not expressing Ep-CAM on their tumours showed an inferior survival (P=0.0014), correlation of Ep-CAM expression with survival did not reach statistical significance for any of the other cancer indications and subgroups. In conclusion, the data strongly support the notion that Ep-CAM is a prime target for immunotherapies in major human malignancies. This is because the most common human cancers show (i) a low frequency of Ep-CAM-negative tumours, (ii) a high frequency of Ep-CAM expression on cells of a given tumour, and (iii) for most cancers, an insignificant influence of tumour staging, grading and histology on Ep-CAM expression.