Study of Efficacy and Safety of Reinfusion of Tisagenlecleucel in Pediatric and Young Adult Patients With Acute Lymphoblastic Leukemia (ALL)

Inclusion Criteria:

   - Signed informed consent must be obtained prior to participation in the study

   - Must have an additional dose of unexpired, commercial tisagenlecleucel available and
   prescribed by a physician in the course of medical practice

   - Age up to and including 25 years

   - Patients must have CD-19+ Leukemia

   - Patients who were previously treated with tisagenlecleucel and present with evidence
   of B-cell recovery as defined by: Peripheral blood (PB) absolute B lymphocyte count ≥
   50/µL, OR PB B lymphocyte ≥ 10% of the total lymphocytes

Exclusion Criteria:

   - Prior gene therapy other than tisagenlecleucel

   - Prior adoptive T cell therapy other than tisagenlecleucel

   - Active CNS involvement by malignancy

   - Active or latent hepatitis B or active hepatitis C, or any uncontrolled infection at
   screening

   - HIV positive test within 8 weeks of screening