This is a Phase 1b/2 study to evaluate the safety and efficacy of autologous T cells engineered with a chimeric antigen receptor (CAR) targeting cluster of differentiation (CD)19 in pediatric patients with relapsed or refractory (r/r) B cell acute lymphoblastic leukemia (B ALL) and r/r B cell Non-Hodgkin lymphoma (B NHL).

This is a single-arm, open-label, multi-center, Phase 1b/2 study to determine the safety and efficacy of obe-cel administered intravenously in pediatric patients < 18 years old with r/r B ALL and with r/r aggressive mature B NHL.

The safety and tolerability of obe cel in pediatric patients will be continually monitored by the Sponsor. Efficacy endpoints will be determined by an Independent Response Review Committee (IRRC).

The study will involve consented patients going through the following sequential study periods: screening, leukapheresis, bridging as necessary, lymphodepletion, treatment evaluation, and follow-up.

INCLUSION CRITERIA:

• < 18 years old at screening
• ≥ 6 kg body weight at screening

Pediatric patients with r/r B ALL

r/r CD19-positive aggressive mature B including the B NHL subtypes: i) diffuse large B cell lymphoma, ii) Burkitt's lymphoma, iii) primary mediastinal large B cell lymphoma, iv) high-grade B cell lymphoma (not otherwise specified).

• Karnofsky (age ≥ 10 years) or Lansky (age < 10 year) performance status score ≥ 50%.
• In participants with B ALL, local documentation of CD19 expression on leukemic blasts in the BM, peripheral blood, or cerebrospinal fluid or biopsy done no more than 30 days prior to consent.
• Adequate renal, hepatic, pulmonary, and cardiac function.

EXCLUSION CRITERIA:

• Diagnosis of chronic myelogenous leukemia in lymphoid blast crisis.
• History or presence of clinically relevant central nervous system (CNS) pathology unrelated to CNS leukemia.
• Presence of active or uncontrolled fungal, bacterial, viral, or other infection requiring systemic antimicrobials for management.
• Received prior (< 3 months before obe cel infusion) stem cell transplantation.
• Prior CD19 targeted therapy other than blinatumomab.
• Experienced Grade ≥ 3 neurotoxicity following blinatumomab.