Study Design:
* The Patients will receive 6 cycles of induction chemotherapy as follows: Anti-CD20/Hyper -CVAD chemotherapy will be alternated with anti-CD20 +MTX/Ara-C chemotherapy. After 4 cycles (2 x2), response will be evaluated. If response (complete or partial) is observed, 2 additional cycles will be administrated. If less than a partial response is observed, the patient will be out of the study.
* Consolidation treatment will be a single dose of Y90Ibritumomab -Tiuxetan (Zevalin) will be administered after 12 weeks after completion of induction chemotherapy. The initial dose of Zevalin will be 0.3 mCi/kg, to be further escalated to 0.4 mCi/Kg if unacceptable toxicity does not occur.
