Paclitaxel/Carboplatin With or Without Cetuximab in CUP

Inclusion Criteria: * Histologic or cytologic proven, non-resectable carcinoma of unknown primary (adenocarcinoma or non-differentiated carcinoma) * Measurable tumor lesion(s) according to RECIST criteria * WHO PS 0 to 1 * Paclitaxel/Carboplatin with or without Cetuximab in Adeno- and Undifferentiated CUP (PACET-CUP) * Signed written informed consent * ≥ 18 years of age * Effective contraception for both male and female subjects if the risk of conception exists * Adequate bone marrow function: * Neutrophiles blood cell count (NBC) ≥ 1,5x109/L * Platelet count ≥ 100x109/L * Hemoglobin ≥ 5,00 mmol/L (8 g/dL) * Adequate liver and renal function: * Bilirubin ≤ 1,5 x upper normal level (UNL) and not increasing more than 25% within the last 4 weeks * ASAT and ALAT ≤ 2,5 x UNL or in case of liver metastases ≤ 5 x UNL * Serum creatinine ≤ 1.5 x UNL Exclusion Criteria: * Previous exposure to epidermal growth factor receptor-targeting therapy * Previous chemotherapy except adjuvant treatment with progression of disease documented \> 6 months after end of adjuvant treatment * Radiotherapy or major abdominal or thoracic surgery within the last 4 weeks before inclusion * Concurrent chronic systemic immunotherapy, chemotherapy or hormone therapy * Investigational agents or participation in clinical trials within 30 days before treatment start in this study * Clinically relevant coronary disease or myocardial infarction within 12 months before study entry * Possibility of a curative local treatment (surgery and/or radiotherapy) * Women with axillary node metastasis as predominant tumor site * Women with peritoneal carcinomatosis as predominant tumor site * Men \< 50 years old with retroperitoneal or mediastinal lymph node +/- lung metastases as predominant tumor site * Identification of the primary or suspicion of a specific tumor entity by reference histopathology (i.e., Her-2 positive or hormone receptor positive tumors corresponding to breast cancer, CK7-negative/CK20- positive tumors with high probability for colorectal cancer) * Peripheral neuropathy \> CTC grade I * Previous malignancy within the last 5 years (except history of basal cell carcinoma of skin or pre-invasive carcinoma of the cervix with adequate treatment) * History of severe psychiatric illness * Life expectancy less than six weeks * Drug or alcohol abuse * Known hypersensitivity reaction to any of the components of the study treatment * Pregnancy (absence to be confirmed by β-hCG test) or lactation period * Brain metastasis and/or leptomeningeal disease (known or suspected) * Acute or sub-acute intestinal occlusion or inflammatory bowel disease