M20-429: The purpose of this study is to assess how safe and tolerable immunotherapy (called epcoritamab) in children with relapsed or refractory aggressive mature B-cell cancers, and young adults with Burkitt's or Burkitt-like lymphoma or leukaemia.A Single Arm, Open-Label, Phase 1b Trial of Epcoritamab in Pediatric Patients With Relapsed/Refractory Aggressive Mature B-cell Neoplasms

Inclusion

• Participants >= 1 and < 18 years old at time of primary diagnosis with Burkitt's or Burkitt-like lymphoma/leukemia, diffuse large B-cell lymphoma (DLBCL), or other aggressive mature (CD20+) B-cell lymphomas. Participants up to 25 years of age with Burkitt's or Burkitt-like lymphoma/leukemia are also eligible.
• Disease pathologically confirmed (tumor tissue) by local testing.

• Relapsed or primary refractory disease meeting any of the following criteria:

  • Progressive disease at any time during second-line chemoimmunotherapy (CIT).
  • Best response of stable disease (SD) after a minimum of 2 cycles of second-line CIT.
  • Best response of partial response (PR) after a minimum of 3 cycles of second-line CIT.
  • Complete Response (CR) after a minimum of 3 cycles of second-line CIT therapy but unfit or ineligible for consolidation with cell therapy.
  • Not in CR and unable to initiate or tolerate (i.e., must discontinue) second-line CIT.
  • Have received cell therapy (allogeneic or autologous transplant or chimeric antigen receptor T-cell (CAR-T) therapy) as consolidation but have not obtained or maintained a CR.
• Recovery from toxic effects of prior chemoimmunotherapy.
• Performance status by Lansky (< 16 years old at evaluation) or Karnofsky (>= 16 years old at evaluation) score >= 50 or Eastern Cooperative Oncology Group (ECOG) score <= 2 .
• Adequate bone marrow, hepatic, and renal function.