Decrease of VEGF within malignant ascites during catumaxomab treatment: Results from a pivotal phase II/III study

3029 Background: Treatment with the trifunctional anti-EpCAM x anti-CD3 antibody catumaxomab efficiently eliminates tumor cells from the peritoneal cavity (Jager et al., ASCO 2007) and led to clinically relevant prolongation of puncture-free survival (PuFS) in patients with malignant ascites (MA) in a pivotal phase II/III trial (Parsons et al., ASCO 2008). As vascular endothelial growth factor (VEGF) levels are markedly elevated in MA in comparison to cirrhotic ascites the question was addressed whether catumaxomab treatment impacts the expression or accumulation of VEGF within MA. Here we report that in addition to tumor cell depletion, VEGF protein levels in MA significantly decreased upon catumaxomab therapy. We propose that the strongly correlated tumor cell elimination and reduced VEGF protein levels are causative for the prolonged PuFS of patients suffering from MA. Methods: VEGF and total protein levels were measured by ELISA and BCA from MA supernatants before catumaxomab therapy, after the 1st in...