The purpose of this clinical trial is to prove the efficacy of the following new regimen treatment:

• Administration of anti-CD20 (Rituximab) combined with chemotherapy.
• Combined treatment with high doses of methotrexate and high doses of cytarabine with conventional cytostatics (block C)
• Prophylactic administration of G-CSF after all chemotherapy cycles
• local irradiation after 6 cycle if CNS was affected or if there are residual tumour

Clinical Trial with a pharmaceutical speciality in new conditions to use.

Inclusion Criteria:

• Patients diagnosed with mature LLA-B cell (LLA-L3)
• Patients diagnosed with Burkitt´s and Burkitt´s Like Lymphoma
• Patients 15 years old or up
• Written Informed Consent signed

Exclusion Criteria:

• Serious complications related with LAL3/LB or Secondary illness:

Serious complications, uncontrollable, for example, sepsis, pneumonia with hypoxia, shock, haemorrhage at diagnosis.

• Renal failure unconditional for the Lymphoma/Leukemia
• Heart failure or serious liver.
• Pulmonary obstructive disease or serious restrictive that not allow to treat the patient with intensive chemotherapy.
• Secondary Lymphoma after chemotherapy or previous radiotherapy or second malignant tumour.
• Known hypersensitivity to any foreign protein.
• Previous treatment with cytostatics of the LLA-B or Burkitt´s Lymphoma (exception: administration on short time of glucocorticoids ≤ 7 days, one administration of vincristine or cyclophosphamide, one cycle of CHOP, urgent administration of the another cytostatics).
• With another malignant tumour in the last 5 year.
• Women in fertile age must give positive in the pregnancy test or nursing mother.
• Mental disability or emotional or psychiatric significant disorder were the patient can't understand nor cooperate with treatment.
• Patients is enrolled in another clinical research study.