<qa>  What is the treatment period for dose escalation?The study is designed as an open-label dose-escalation study to investigate the safety and tolerability of catumaxomab qwk in patients with epithelial cancer. The treatment period for dose escalation dose limiting toxicity DLT period consists of 4 weeks, comprising 4 single i.v. administrations of catumaxomab followed by 1 week for safety observations after each administration. All patients will be offered continuation of catumaxomab treatment at the same dose until disease progression or death, whichever occurs first. 