Clinical benefit of catumaxomab in malignant ascites in patient subpopulations in a pivotal phase II/III trial
e14000 Background: Parsons et al. (ASCO 2008) reported the results of a pivotal phase II/III trial in patients with malignant ascites due to epithelial cancer. Treatment with the trifunctional antibody catumaxomab resulted in a clinically relevant prolongation of puncture-free survival, defined as the time to the next therapeutic puncture or the time to death, whichever occurred first. Malignant ascites is a typical late-stage manifestation of cancer associated with a poor prognosis and survival. Effective treatment options are limited. It is thus of special interest if all patient subgroups derive objective benefit from treatment. Methods: A post-hoc analysis was performed on the 258 patients with epithelial tumors treated with catumaxomab + paracentesis or paracentesis alone (control) in the pivotal trial to investigate any association between the primary endpoint (puncture-free survival) and the primary tumor, metastases, or other prognostic parameters. Results: Puncture-free survival was lower in patients with non-ovarian vs ovarian tumors and those with a poor prognosis (metastases vs no metastases, elderly vs younger, or low vs serum protein level). However, there was always a statistically significant treatment effect for catumaxomab compared with the respective control group (p≤0.0001, log rank test, for all comparisons) (see table). Conclusion: Catumaxomab demonstrated a significant clinical benefit in patients with malignant ascites independent of the primary tumor or other prognostic factors. Therefore, catumaxomab could be considered as a treatment option for patients with a poor prognosis. [Table: see text] [Table: see text]