Peritoneal carcinomatosis immunotherapy with the trifunctional anti-EpCAM x anti-CD3 antibody catumaxomab in patients with colon, gastric, or pancreatic cancer: Long-term results after a 2-year follow-up

Abstract

3033 Background: Peritoneal carcinomatosis (PC) from gastrointestinal (GI) cancer is associated with a poor outcome. The trifunctional antibody catumaxomab may induce remission by redirecting T-lymphocytes and Fcγ-receptor I/III positive accessory cells to tumor cells. The aim of this study was to investigate the treatment of PC with intraperitoneal catumaxomab. Methods: Patients with epithelial cell adhesion molecule (EpCAM)-positive PC from GI cancer were enrolled in a multicenter phase I study and received four sequential intraperitoneal catumaxomab infusions on days 0, 3, 7, and 10 at increasing doses. Results: Twenty-four patients were enrolled. The maximum tolerated dose (MTD) was reached at 10, 20, 50, and 200 μg on days 0, 3, 7, and 10, respectively. The most common drug-related adverse events at the MTD were fever, vomiting, abdominal pain, skin toxicity, and nausea. Eleven of 17 evaluable patients (65%) were progression-free at final examination: one patient had a complete response and three patients had a partial response. EpCAM-positive cells in peritoneal lavage samples decreased in six of 10 evaluable patients. Patient survival was compared in a post hoc matched-pair analysis with PC patients treated with conventional intravenous chemotherapy. Median survival from the time of diagnosis of PC was 502 days in study patients versus 180 days in control patients (log-rank p = .0083). Conclusions: Intraperitoneal treatment with catumaxomab had an acceptable safety profile. Elimination of tumor cells from peritoneal lavage samples, delayed disease progression, and prolonged survival indicate that intraperitoneal catumaxomab is a promising option for the treatment of PC from GI cancer. [Table: see text]