A Study to Assess Adverse Events and How Pivekimab Sunirine Moves Through the Body of Pediatric Patients with Relapsed or Refractory Acute Myeloid Leukemia (AML)

Prior treatment

• Participant has prior history of any severity VOD/SOS (veno-occlusive disease/sinusoidal obstructive syndrome) of the liver.
• Participants who have received prior CAR-T therapy

Other illness

• Participant has known clinically significant cardiac disease.
• Participant with Down syndrome
• Participant has symptomatic central nervous system (CNS3) disease

Other

• Participant has acute promyelocytic leukemia (APL) or juvenile myelomonocytic leukemia (JMML)

• Participants must have histologically confirmed AML meeting one of the following disease criteria:• Second or greater relapse OR • Disease refractory to second or subsequent line of therapy (defined as resistant disease after at least one cycle of each treatment regimen)
• Participants must have myeloid leukemic blasts that are CD123-positive by flow cytometry as determined by the treating institution.
• Participant has ≥5% myeloid leukemic blasts in bone marrow at time of relapse or refractory disease and prior to Screening for this study.
• Performance status by Lansky (< 16 years old at evaluation) or Karnofsky (≥ 16 years old at evaluation) score ≥ 50 or ECOG score ≤ 2.
• Participants may have status of CNS1, CNS2, or CNS3 disease without clinical signs or neurologic symptoms suggestive of CNS leukemia, such as facial nerve palsy, brain/eye involvement or hypothalamic syndrome. Participants may have non-CNS extramedullary disease.