Safety and Efficacy Study With Catumaxomab in Patients After Curative Resection of a Gastric Adenocarcinoma

Inclusion Criteria: * Signed and dated informed consent * Patient has a primary diagnosis of a histologically confirmed gastric adenocarcinoma (including GE junction Siewert-Type 2 or 3) * Intended curative gastrectomy ('en-bloc´-R0-resection considering the standard D2-scheme) * Serosal infiltration (T3/T4, N+/-, M0) confirmed by immediate section with histopathologic assessment during surgery * Karnofsky index \>= 70 * Negative pregnancy blood test at screening in women with childbearing potential Exclusion Criteria: * Presence of distant metastases * Macroscopic and microscopic residual tumor present after surgery * State after pancreas resection or thoracotomy * Exposure to prior cancer therapy or planned adjuvant chemo-or radiotherapy of the current gastric cancer * Previous treatment with non-humanized mouse or rat monoclonal antibodies * Known/suspected hypersensitivity to catumaxomab or similar antibodies * Any cancer disease or any cancer treatments within the last 5 years * Presence of constant immunosuppressive therapy * Inadequate renal function (creatinine \> 1.5 x ULN) * Inadequate hepatic function (AST or ALT \> 2.5 x ULN or bilirubin \>= 1.5 x ULN) * Platelets \< 75000 cells/mm³; absolute neutrophil count \< 1500 cells/mm³ * Patient had a bowel obstruction within the last 30 days * Pregnant or nursing woman, or woman of childbearing potential who is not using an effective contraceptive method during the study and at least contraceptives, intrauterine devices, double-barrier method, contraceptive patch, male partner sterilization or condoms) * Presence of any acute or chronic systemic infection * Any further condition which according to the investigator results in an undue risk to the patient during participating in the present study * Patient is an employee of any involved study investigator or any involved institution including the study sponsor * Parallel participation in another clinical trial or previous participation in this study * Treatment with another investigational product during this study or during the last 30 days prior to study start