Targeted Immunotherapy After Myeloablative TBI-Based Conditioning & AlloHCT in CAYA With High Risk T-Cell ALL & Lymphoma

Total body irradiation (TBI)-based myeloablative allogeneic hematopoietic stem cell transplantation (HCT) using best available donor. Daratumumab (DARA) treatment post-HCT: Phase 1: 3 dose levels to determine safety (15 patients) Dose expansion cohort (DEC): Further evaluation of PK and PD (correlative studies/exploratory endpoints) to guide future selection of RP2D (15 patients) Treatment Schedule: 1. Induction: DARA IV weekly x 8 doses (Weeks 1-8) 2. Consolidation: DARA IV every 2 weeks x 8 doses (Weeks 9-24) 3. Maintenance: DARA IV every 4 weeks (Stop at Day +270)