Two-year follow-up of a phase II study on catumaxomab as part of a multimodal approach in primarily resectable gastric cancer.

Abstract

4095^ Background: Perioperative chemotherapy (CT) has demonstrated as survival benefit in locally advanced gastric cancer (GC) in randomized trials. However, the overall cure rate is 30-40% and a significant number of patients are not able to receive the postoperative part of their CT regimen. In Europe, the trifunctional antibody catumaxomab is approved for the treatment of malignant ascites based on a pivotal trial which also included GC patients. A new multimodal approach combining neoadjuvant CT, followed by gastrectomy and intraperitoneal (i.p.) immunotherapy with catumaxomab was assessed in a single-arm multicenter phase II study. We here report 2-year follow-up data. Methods: GC pts (T2/T3/T4, N+/–, M0) received 3 cycles of neoadjuvant fluoropyrimidin/platinum-based CT followed by ’en-bloc’ R0-gastrectomy. Catumaxomab was administered i.p. as intraoperative bolus (10 µg) followed by 4 consecutive 3-hour infusions of 10-150 µg. Primary safety endpoint was the rate of predefined postoperative complications observed during 30 days after surgery. Key efficacy endpoints included disease-free (DFS) and overall survival (OS). Results: The original study data presented at the WCGC in 2011 (Schuhmacher et al.,Ann Oncol (2011) 22(suppl. 5)) showed that the primary endpoint was met and the described application regimen is safe. At time of surgery, 27.8% of patients were stage I, 27,8% of patients were stage II, 22,3% of patients were stage III and 14,8% of patients were stage IV as assessed according to pTNM measures. At 24 months 39/54 (safety analysis set) patients were still alife,14/54 were dead, (one patient lost to follow-up), 24/37 had no progression, only 13/37 patients relapsed (for 2 patients disease status was not recorded). At the 2 year cut off DFS was 56.4% (95% CI: 41–69%), OS was 75% (95% CI: 60–85%). Conclusions: Catumaxomab as part of a multimodal therapy in primarily resectable GC is a feasible option. The 2-year follow up efficacy results show promising data for DFS and OS in a cohort of locally advanced gastric cancer pts.