Patients younger than 55 years in complete response after two blocks of rituximab and specific intensive chemotherapy will receive four additional blocks of rituximab and attenuated chemotherapy (reduction by 33% of the dose of cyclophosphamide, methotrexate and cytarabine) followed by additional rituximab doses as consolidation. Patients older than 55 years will receive the six blocks with attenuated chemotherapy.
Rituximab combined with a specific intensive chemotherapy is considered the standard treatment for newly diagnosed patients with mature B leukemia/lymphoma. However, the toxicity of this therapy is high. The purpose of this trial is to reduce the dose intensity of the chemotherapy blocks once the patient has achieved complete response. With this approach the investigators expect to maintain the efficacy and to reduce the toxicity of the chemotherapy, specially the rate of deaths in complete response.