A Study of Sonrotoclax (BGB-11417) in Children With Relapsed or Refractory Acute Myeloid Leukemia and B-cell Acute Lymphoblastic Leukemia

Key Inclusion Criteria

Participants must meet all of the following criteria to be eligible for participation:

1. Have a performance status of Lansky ≥50 for participants ≤16 years of age or Karnofsky ≥50 for participants \>16 years of age.
2. Have adequate renal function, defined as an estimated or measured glomerular filtration rate (GFR) ≥60 mL/min.
3. Have adequate hepatic function, defined as:

   * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) \<2.5 × the institutional upper limit of normal (ULN)
   * Total bilirubin ≤1.5 × the institutional ULN.
4. Have minimum cardiac function as defined in the study protocol.

Acute Myeloid Leukemia (AML)-Specific Inclusion Criteria

1. Have a histologically confirmed diagnosis of acute myeloid leukemia (AML) that is relapsed or refractory (R/R) after ≥2 prior lines of systemic therapy.
2. Have ≥5% blasts in a bone marrow aspirate or biopsy sample, as assessed by morphology. Participants with extramedullary, non-central nervous system (CNS) disease are eligible.

B-Cell Precursor Acute Lymphoblastic Leukemia (ALL)-Specific Inclusion Criteria

1. Have a histologically confirmed diagnosis of B-cell precursor acute lymphoblastic leukemia (ALL) that is R/R after ≥2 prior lines of systemic therapy, including at least 1 line of blinatumomab-based therapy.
2. Have ≥5% blasts in a bone marrow aspirate or biopsy sample, as assessed by morphology.
3. Have leukemic blasts expressing cluster of differentiation 22 (CD22) on the cell surface, as assessed by flow cytometry of a bone marrow aspirate.

Key Exclusion Criteria

Participants will be excluded from participation if any of the following apply:

1. Have central nervous system (CNS) 2 or CNS 3 disease at screening.
2. Have toxicity from prior anticancer therapy that has not recovered to ≤Grade 1, as defined by the applicable toxicity grading criteria.
3. Have a history of prior allogeneic stem cell transplantation \<90 days from enrollment or if if ≥ 90 days from enrollment, with active graft-versus-host disease (GVHD), or requiring immunosuppressive drugs for treatment of GVHD, or have taken calcineurin inhibitors within 4 weeks prior to consent.

AML-Specific Exclusion Criteria

1. Have a diagnosis of acute promyelocytic leukemia (APL) or juvenile myelomonocytic leukemia (JMML).
2. Have AML with fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD), as determined by local assessment.

ALL-Specific Exclusion Criteria

1. Have Philadelphia chromosome-positive (Ph+) ALL with a breakpoint cluster region::Abelson murine leukemia viral oncogene homolog 1 (BCR::ABL1) fusion.
2. Have received prior therapy with a B-cell lymphoma 2 (BCL-2) inhibitor.

Note: Other eligibility criteria may apply.