EpCAM is expressed in normal gastric tissue, though its receptor is typically “hidden” by its closely-associated tight junctions. After undergoing malignant transformation, these tight junctions are lost, and the EpCAM antigen becomes more readily available for binding. Up to 98% of gastric cancer cells will express EpCAM on the cell surface.6

Catumaxomab is available only in Europe, though it may be reviewed for approval in the United States. It is approved for use in patients with malignant ascites secondary to EpCAM-positive epithelial cancers.


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Catumaxomab is administered as an intraperitoneal infusion on a series of 4 days at increasing doses.7 A study of 258 patients with malignant ascites was conducted to evaluate the efficacy and safety of catumaxomab; this study included patients with ovarian or non-ovarian malignancies, and evaluated the time to first therapeutic paracentesis (“puncture”) and puncture-free survival.

The median puncture-free survival was significantly longer in the catumaxomab group (46 days) compared to the control group (11 days). The median time to the next paracentesis was also longer in the catumaxomab group (77 days) compared with the control group (13 days).

Out of all the subtypes of cancer patients included, gastric cancer patients were the only ones to have a statistically significant increase in overall survival (71 vs 44 days).

Trifunctional antibodies such as catumaxomab are an exciting new class of mAbs that may have a significant impact in treating malignancies. Although the data are still accumulating, catumaxomab may provide a clinical benefit in patients with malignant ascites.

References

  1. Fan G, Wang Z, Hao M, Li J. Bispecific antibodies and their applications. J Hematol Oncol. 2015;8:130.
  2. Removab prescribing information. HemOnc.org website. http://hemonc.org/docs/packageinsert/catumaxomab.pdf. Accessed October 2016.
  3. Litvinov SV, Velders MP, Bakker HA, Fleuren GJ, Warnaar SO. Ep-CAM: a human epithelial antigen is a homophilic cell-cell adhesion molecule. J Cell Biol. 1994;125(2):437-46.
  4. Runyon BA, Montano AA, Akriviadis EA, Antillon MR, Irving MA, McHutchison JG. The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites. Ann Intern Med. 1992;117(3):215-20.
  5. Ayantunde AA, Parsons SL. Pattern and prognostic factors in patients with malignant ascites: a retrospective study. Ann Oncol. 2007;18(5):945-9.
  6. Went P, Vasei M, Bubendorf L, et al. Frequent high-level expression of the immunotherapeutic target Ep-CAM in colon, stomach, prostate and lung cancers. Br J Cancer. 2006;94(1):128-35.
  7. Heiss MM, Murawa P, Koralewski P, et al. The trifunctional antibody catumaxomab for the treatment of malignant ascites due to epithelial cancer: Results of a prospective randomized phase II/III trial. Int J Cancer. 2010;127(9):2209-21.