VHR ALL: Treatment of Pediatric Very High-risk Acute Lymphoblastic Leukemia in Korea

* Pediatric patients diagnosed with ALL between the ages of 1 and 19 years at the time of diagnosis who meet one or more of the following conditions:

* Philadelphia chromosome-positive t(9;22)(q34;q11) or

* Patients with failed remission who had blast > 5% on bone marrow test after initial remission induction therapy or

* Hypodiploidy (Number of chromosomes < 44 (less than 44)) or

* E2A-HLF(Hepatic Leukemia Factor) translocation-positive or

* When the prognosis is judged to be poor according to NGS-MRD results among high-risk ALL patients (i) In B-ALL, the NGS-MRD(Next Generation Sequencing-Minimal Residual Disease) after consolidation therapy is 0.01% or more, and the NGS-MRD followed during interim maintenance treatment is also 0.01% or more, (ii) In T-ALL, NGS-MRD(Next Generation Sequencing-Minimal Residual Disease) is more than 0.01% after consolidation therapy

* Participants with contraindications to medications

* When the study participant or their legal representative withdraws consent

* Pregnant or lactating women (patients of child-bearing potential require adequate contraception during the study period)

* Participants who are medically unsuitable to participate in this study at the discretion of the investigator Participants participating in other interventional studies other than this protocol