The association of Rituximab fludarabine cyclophosphamide leads to the best response rate with 52 to 72% CR in "medically" fit untreated CLL patients. MRD results in this setting are still preliminary and around 50%. However many other situations (unfit, elderly, relapse, haematological toxicity leading to early interruption of treatment…) are associated with much lower response rate that would be improved by consolidation treatment.