Primary: To estimate efficacy of SR29142 to the pediatric patients with newly diagnosed hematological malignancies at high risk for Tumor Lysis Syndrome, by evaluation of plasma uric acid concentration.

Secondary: To investigate the safety in this population and anti-SR29142 antibodies, anti-SCP antibodies, and pharmacokinetic parameters.

Inclusion Criteria:

• <18 years of age
• Patient with newly diagnosed hematological malignancies presenting with hyperuricemia:
• Uric acid > 7.5 mg/dL in patients ≥ 13 years old- Uric acid > 6.5mg/dL in patients <13 years old

Or, patient with newly diagnosed hematological malignancies presenting with high tumor burden defined:

• Non-Hodgkin's lymphoma, Stage IV regardless of uric acid level,

• Non-Hodgkin's Lymphomas stage III regardless of uric acid level with one of the following:

  • At least one lymph node or mass >5 cm in diameter
  • LDH ≥ 3 x ULN (IU/L): Judging according to modified Murphy's classification

• Acute leukemia with white blood cell count (WBC) ≥ 50,000/mm3 or LDH ≥ 3 x ULN (IU/L) regardless of uric acid level. etc.

Exclusion Criteria:

• Patients who have received or are scheduled to receive other investigational drugs in 30 days prior to the start of SR29142 administration or during the trial period.
• Low birth weight infant (<2500g) or gestational age <37 weeks
• Patients who have received or are scheduled allopurinol within 72 hrs prior to the first dose of SR29142 or during the trial period.
• Known history of severe allergic reaction and/or severe asthma.
• Known history or family history of glucose-6-phosphate dehydrogenase deficiency.
• Known history of hemolysis and methemoglobinemia.
• Severe disorders of liver or kidney. ALT (GPT) > 5.0 x ULN, Total Bilirubin > 3.0 x ULN, Creatinine > 3.0 x ULN
• Uncontrollable infections (including viral infections).
• Known positive tests for HBs antigen, HCV antibodies, or HIV-1, 2 antibodies. etc.