504 - Second Cycle of Catumaxomab Treatment in Patients with Malignant Ascites: Results from the Secimas Study

Abstract

ABSTRACT Purpose The SECIMAS study investigated the feasibility of a second cycle of 4 intra-peritoneal (i.p.) infusions of catumaxomab in patients who responded to treatment with 4 i.p. catumaxomab infusions in the CASIMAS study. Patients and methods Eligible patients had to have completed 4 i.p. prior infusions of catumaxomab in the CASIMAS study and required their first therapeutic puncture after > 60 days. Primary endpoint was the proportion of patients who were able to receive at least 3 infusions. Secondary endpoints were safety including a composite safety score (CSS) summarizing the worst CTCAE grades for the main TEAEs (pyrexia, nausea, vomiting, and abdominal pain) and the development of anti-drug antibodies (ADA). Efficacy endpoints were puncture-free survival (PuFS), time to puncture (TTPu) and overall survival (OS). Results Eight of 9 selected patients from the CASIMAS study were treated with a 2nd of catumaxomab. Eight (100%) patients received all 4 infusions within 20 days, thus the primary endpoint was met with a high compliance rate. The median CSS was comparable for these 8 patients with 3.4 after the first cycle and 3.0 after the second cycle. Less patients in the SECIMAS study had AEs with CTC >3 (25%) compared to CASIMAS (70.1%). All 8 (100%) patients were ADA-positive at study entry and remained ADA-positive throughout treatment. PuFS was 47.5 days (28;181) and TTPu 60 days (34;na) after the 2nd cycle, while it was 37 days (24;61) and 102 days (69;159), respectively after the first cycle. OS was 406.5 days (281;480) in the SECIMAS study and 201 days (169;241) in the CASIMAS study. Conclusions The study demonstrates that despite the advanced stage of disease and the presence of ADA, a second cycle of i.p. catumaxomab treatment is feasible and well tolerated in selected patients suffering from malignant ascites and requiring treatment for ascites after a first cycle of catumaxomab. These patients actually seem to benefit from the second cycle catumaxomab in the same range as after the first cycle. Disclosure I.B. Vergote: consultant for Fresenius Biotech GmbH. A. Santoro: financial support for Fresenius Biotech GmbH. F. Marme: financial support for clinical studies from Fresenius Biotech GmbH. P. Rosenberg: financial support for clinical studies from Fresenius Biotech GmbH. J. Sehouli: consultant for Fresenius Biotech GmbH and financial support for clinical studies. All other authors have declared no conflicts of interest.