Isatuximab in Combination With Chemotherapy in Pediatric Patients With Relapsed/Refractory Acute Lymphoblastic Leukemia or Acute Myeloid Leukemia

Inclusion criteria: * Participant 28 days to less than 18 years of age, at the time of signing the informed consent. * Participants must have had a confirmed diagnosis of relapsed Acute Lymphoblastic Leukemia (ALL) of T- or B-cell origin including T-lymphoblastic lymphoma (LBL), or relapsed Acute Myeloblastic Leukemia (AML) including participants with history of myelodysplasia. * Participants must have been previously treated for their disease and have relapsed or are refractory to most recent treatment. Participants in first or second relapse were eligible regardless of the remission duration. * Participants who had no more than 1 prior salvage therapy. * White Blood Cell (WBC) counts below 20 x10\^9/L on Day 1 before isatuximab administration Exclusion criteria: * Any serious active disease or co-morbid condition which, in the opinion of the Investigator, may interfere with the safety of the study treatment or the compliance with the study protocol. * Participants must have been off prior treatment with immunotherapy/investigational agents and chemotherapy for \>2 weeks and must have recovered from acute toxicity before the first study treatment administration. Exceptions were participants who needed to receive cytoreductive chemotherapy in order to decrease tumor burden (the study treatment may have started earlier if necessitated by the patient's medical condition (eg, rapidly progressive disease) following discussion with the Sponsor). * Prior stem cell transplant wit…