In Part A, between one and four groups of 5 patients will receive doses of otelixizumab administered over 8 days. The first dose level will provide a low cumulative dose, this low dose level has been safely administered in previous studies. Safety and clinical response data will be reviewed after 8 weeks, if no clinical response is seen and there are no safety concerns, the dose of otelixizumab will be increased and a new group of subjects will enter Part A. In subsequent groups cumulative medium low, medium high, and high doses of otelixizumab may be investigated. However if a clinical response is seen at the lowest dose the study will move directly to Part B.