1) diagnosis of T-ALL (CD3+ or cyCD3+ and more than one is positive among CD2, CD5, CD7, CD8)
2) age less than 25 years old
3) ECOG performance status (PS) acore of 0-2.However, PS scores up to 3 are permitted when the deterioration of PS is thought to be due to leukemia.
4) no history of previous chemotherapy or radiation therapy
5) sufficient hepatic and renal function satisfying the laboratory data listed below ;
(1)T-Bili: within 3x of age adjusted upper-limit of normal range.
(2)Creatinine: within 3x of age adjusted upper-limit of normal range.
6) written informed consent obtained from patient or guardians.
1) Intracranial hemorrhage more than grade 3 of CTCAE v4.0
2) uncontrolled infection, including active tuberculosis and positive of HIV antibody.
3) pregnancy or high possibility of pregnancy and giving suck woman.
4) history of congenital or acquired immunodeficiency.
5) Down syndrome.
6) QTfc, corrected by Fridericia formula as QTfc = QT/RR cube root, is more than 0.45 seconds.
7) any inappropriate status judged by physician.
Stratification(SR/HR/VHR) based on early prednisolone response, remission induction at time-point1(TP1) and MRD at time-point2(TP2).
SR: Early prednisolone good responder (PGR), Time-point1(TP1):BM=M1 and TP2:MRD<10^-3 .
Clinical study question: safety and effectiveness of BFM-MR regimen with intensive L-asp and without Nelarabine.
HR: Early prednisolone poor responder (PPR), TP1:BM=M1 and TP2:MRD<10^-3 .
Clinical study question: safety and effectiveness of BFM-HR regimen with intensive L-asp and Nelarabine.
VHR: TP1:BM=M1 and TP2:MRD>=10^-3 or TP1:BM=M2/M3 and TP2:BM=M1.
Clinical study question: rondamization ; BFM-HR block regimen vs high-dose dexamethazine containing regimen.