* Hepatic: AST and ALT \< 5x the upper limit of normal for age, unless thought to be leukemic disease-related
* Renal: Calculated glomerular filtration rate (GFR) ≥ 70 ml/min/1.73m\^2. (based on Schwartz formula GFR (mL/min/1.73 m²) = (36.2 × Height in cm) / Creatinine in mg/dL
* Cardiac: LVEF ≥ 50% by multi-gated acquisition scan (MUGA), resting echocardiogram, or cardiac magnetic resonance imaging (MRI) within 6 weeks of screening
* Pulmonary: Oxygen saturation as recorded by pulse oximetry of ≥ 90% on room air
Adequate performance status:
* Age ≥ 16 years: ECOG ≤ 1 or Karnofsky \> 60% at treatment
* Age \< 16 years: Lansky ≥ 60% at treatment
Willing to participate as research subject and provide written informed consent from parents/legal representative, patient, and age-appropriate assent as appropriate before any study specific screening procedures are conducted, according to local, regional or national law and legislation.
You may not be if
Have a known immediate or delayed hypersensitivity reaction or idiosyncrasy to the study drugs, or drugs chemically related to study treatment or excipients that contraindicate their participation, including fludarabine, cyclophosphamide and tisagenlecleucel.
Patients with tisagenlecleucel that is deemed out of specification (OOS) will be excluded from this protocol
Clinically significant active and uncontrolled infection confirmed by clinical evidence, imaging, or positive laboratory tests (e.g., blood cultures, PCR for DNA/RNA etc.)
Patient/parent/guardian unable to give informed consent or unable to comply with the treatment protocol.
Pregnant or lactating women
Clareo Health | A Study of Fludarabine Dosing in Children and Young Adults With B-cell Acute Lymphoblastic Leukemia
