To evaluate the outcome of a prednisolone and low dose methotrexate based protocol in Down syndrome children with ALL (DS-ALL) in an Asia-wide study. The treatment protocol was modified based upon backbone of Taiwan Pediatric Oncology Group (TPOG)-ALL protocol in which risk classification will be guided by level of flow minimal residual disease (MRD) instead.

Inclusion Criteria:

• Down syndrome diagnosed clinically or cytogenetically (including Mosaic Down)
• Newly diagnosed ALL according to WHO 2016 classification.
• Age < 21 years old at time of enrollment.
• ECOG performance status (PS) score of 0-2.
• Written informed consent obtained from legally acceptable representatives.

Exclusion Criteria:

• Second malignancy.

• Philadelphia positive ALL.

• Mature B-ALL.

• Mixed phenotype acute leukemia.

• Any previous treatment with cytotoxic chemotherapy excluding treatment for TAM or radiation therapy. Patient pre-treated with short term steroid (< 7 days of duration within last 1 month prior to treatment start) can be enrolled into this study.

• Renal dysfunction with creatinine >2x upper limit of normal (ULN). Patients whose creatinine has improved to <2x ULN before treatment commencement can enrol subject to discretion of site PI.

• Liver dysfunction with direct bilirubin > 5x ULN.

• Any serious uncontrolled medical condition or impending end organ dysfunction that would impair the ability of the subject to receive protocol therapy, including:

  1. History of coronary arterial disease, cardiomyopathy, heart failure, arrhythmia (other than sinus arrhythmia) or severe cardiac malformation which with residual abnormalities or requires further major corrective surgery within 2 years.
  2. Ongoing uncontrolled hypertension.
  3. Ongoing uncontrolled diabetes mellitus.
  4. Ongoing uncontrolled infection.
  5. History of congenital or acquired immunodeficiency including HIV infection.
  6. History of interstitial pneumonia, pulmonary fibrosis, bronchiectasis or severe pulmonary emphysema.
  7. CNS hemorrhage.
  8. Psychiatric disorder.
  9. Other concurrent active neoplasms.

• Pregnant or lactating women.

• Doubtful compliance or ability to complete study therapy due to financial, social, familial or geographic reason, or in the judgement of site investigator.