Inclusion Criteria:
1. Diagnostic bone marrow samples available to develop an MRD probe
2. Age >1 year and ≤21 years old
3. Newly diagnosed de novo ALL (B-ALL or T-ALL) or mixed phenotypic acute leukaemia (MPAL) with definitive evidence of BCR-ABL1 fusion by karyotype, FISH and/or RT-PCR
4. Patient must have started induction therapy including vincristine, a corticosteroid, usually PEG-L-asparaginase, with or without anthracycline and/or other standard cytotoxic chemotherapy
5. Patient has not received more than 14 days of multiagent induction therapy beginning with the first dose of vincristine
6. Patient may have started imatinib prior to study entry, but has not received more than 14 days of imatinib
7. ECOG performance status 0-2
8. Adequate liver function:
- Direct bilirubin ≤2.0 mg/dl
9. Adequate cardiac function:
- Shortening fraction of ≥27% by echocardiogram, or
- Ejection fraction of ≥50% by radionuclide angiogram or echocardiogram
- Corrected QT Interval, QTc
10. Adequate renal function
- Creatinine clearance or radioisotope GFR ≥70ml/min/1.73m2or
- Serum creatinine within normal limits forage/gender
Exclusion criteria
1. Known history of chronic myeloid leukaemia (CML)
2. ALL developing after a previous cancer treated with cytotoxic chemotherapy
3. Active, uncontrolled infection or active systemic illness that requires ongoing vasosupressor support or mechanical ventilation
4. Down syndrome
5. Pregnancy and breast feeding:
- Female patients who are pregnant (pregnancy test required for WOCBP)
- Lactating females who plan to breastfeed their infant
- Sexually active patients of reproductive potential who have not agreed to use an effective contraceptive method for the duration of their study participation
6. Patients with congenital long QT syndrome, history of ventricular arrhythmias or heart block
7. Prior treatment with dasatinib, or any BCR-ABL1inhibitor other than imatinib