- Male or female participants between 1 and <18 years of age.
- Morphologically confirmed diagnosis of first relapse HR BCP ALL; HR first relapse is defined as relapse occurring within 18 to 30 months of original diagnosis of ALL or within 6 months of completion of primary therapy, and lacking any identified very high-risk genetic abnormalities (Groeneveld-Krentz et al, 2019) (ie, KMT2A::AFF1 fusion [t(4;11)(q21;q23)], TCF3-HLF fusion [t(17;19)(q22;p13)], TCF3-PBX1 fusion [t(1;19)(q23;p13.3)], hypodiploidy [<40 chromosomes] or masked low hypodiploidy (Molina et al, 2021), TP53 alteration).
- CD22-positive ALL as defined by local institution;
- Bone marrow involvement of ≥ 5% leukemic blasts (≥ M2 status).
- Adequate serum chemistry parameters:
- An eGFR in participants 1 to <2 years of age, or eCrCl in those 2 to <18 years of age, ≥30 mL/min using the recommended formula in Section 10.10.2.
- AST and ALT ≤5 × institutional ULN at the time of randomization or pre-cytoreduction/general anesthesia;
- Total bilirubin ≤1.5 × institutional ULN unless the participant has documented Gilbert's syndrome;
- Prior history of thrombosis during corticosteroid use and/or asparaginase are eligible provided the patient receives anti-coagulant prophylaxis per institutional guidelines.
- Cardiac shortening fraction ≥ 30% by echocardiogram or ejection fraction >50% by MUGA.
6 Participants with combined bone marrow and testicular relapse are eligible assuming orchiectomy is performed prior to randomization or is planned at the end of induction therapy.
5.2.
