Since there is no standard rescue therapy for refractory CLL or relapsed to the purine analogous, our target is to carry out a rescue therapy combining several chemotherapy agents (CHOP) adding the synergistic effect of Rituximab in order to act against tumour-like CLL forms, with assessable size lymph nodes. Afterwards, based in other studies, we shall study the role of Alemtuzumab as drug for consolidation or improvement of responses obtained with the initial therapy (CHOP-R), acting by "cleaning" from peripheral blood and bone marrow the CLL lymphocytes that may have had remain as residual after chemotherapy induction therapy. More precisely, the addition of Alemtuzumab as maintenance treatment would increase the complete responses with negative residual disease number and may prolong the duration of the response. For this, it is necessary to have not only an adequate and rigorous clinical follow-up but also biological, i.e. being able to analyze minimal residual disease by molecular biology techniques. This is the reason of writing this phase II clinical trial protocol.