A Study to Learn More About the Study Medicine Called Inotuzumab Ozogamicin (InO) in Children (1 to <18 Years) With First Relapse ALL

Inclusion Criteria:

1. Male or female participants between 1 and \<18 years of age.
2. Morphologically confirmed diagnosis of first relapse HR or VHR 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). VHR first relapse is defined as relapse within 18 months of original diagnosis of ALL and/or with any of the following genetic abnormalities at original diagnosis or at relapse (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).
3. 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; (Refer to Appendix 9 for France-specific requirement on the ALT/AST threshold);
   * Total bilirubin ≤1.5 × institutional ULN unless the participant has documented Gilbert's syndrome;
4. Prior history of thrombosis during corticosteroid use and/or asparaginase are eligible provided the patient receives anti-coagulant prophylaxis per institutional guidelines.
5. 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. Exclusion Criteria

1. Any history of prior or ongoing hepatic SOS or prior liver failure \[defined as severe acute liver injury with encephalopathy and impaired synthetic function (INR of ≥1.5)\].
2. Prior allo-HSCT or CAR T-cell therapy.
3. Isolated extramedullary leukemia.
4. Philadelphia-chromosome positive ALL, ie. BCR-ABL/t(9;22) present.
5. Prior therapy with a calicheamicin-conjugated antibody (eg, InO or gemtuzumab ozogamicin).
6. Participants with active, uncontrolled bacterial, fungal, or viral infection.
7. Hypersensitivity/allergy to both PEG-ASP and Erwinia-ASP