CD19 CAR-T Consolidation Therapy for Acute Lymphoblastic Leukemia

Phase 1: Optimal biological doses of feeding T cells (FTCs) identification. ssCART-19 cells combined with CD19+ FTCs were administered to Philadelphia chromosome-positive B-ALL patients with remission. ssCART-19 was infused at the dose of 5×10\^6/kg on days 1 to 3 of the first cycle and on day 1 of the second to fourth cycle. CD19+ FTCs (5×10\^6 cells/kg) were infused two hours after the infusion of ssCART-19 cells on day 1 and at the same dose alone on day 8 of the second to fourth cycle. Five patients were enrolled in this arm, and all the patients received four cycles of ssCART-19 consolidation.

Phase 1: Optimal biological doses of feeding T cells (FTCs) identification. ssCART-19 cells combined with CD19+ FTCs were administered to Philadelphia chromosome-positive B-ALL patients with remission. ssCART-19 was infused at the dose of 5×10\^6/kg on days 1 to 3 of the first cycle and on day 1 of the second to fourth cycle. CD19+ FTCs (3.25×10\^6 cells/kg) were infused two hours after the infusion of ssCART-19 cells on day 1 and at the same dose alone on day 8 of the second to fourth cycle. Four patients were enrolled in this arm, and all the patients received four cycles of ssCART-19 consolidation.

Phase 1: Optimal biological doses of feeding T cells (FTCs) identification. ssCART-19 cells combined with CD19+ FTCs were administered to Philadelphia chromosome-positive B-ALL patients with remission. ssCART-19 was infused at the dose of 5×10\^6/kg on days 1 to 3 of the first cycle and on day 1 of the second to fourth cycle. CD19+ FTCs (2×10\^6 cells/kg) were infused two hours after the infusion of ssCART-19 cells on day 1 and at the same dose alone on day 8 of the second to fourth cycle. Four patients were enrolled in this arm, and all the patients received four cycles of ssCART-19 consolidation.

Phase 2: Expansion Study. ssCART-19 cells combined with FTCs at the optimal biological dosage determined in the Phase 1 study were given to expanded Philadelphia chromosome-positive B-ALL patients with remission. The 5×10\^6 cells/kg of CD19+ FTCs was the optimal biological dose determined in phase I. Therefore, CD19+ FTCs at 5×10\^6 cells/kg were infused two hours after the infusion of ssCART-19 cells on day 1 and at the same dose alone on day 8 of the second to fourth cycle, while ssCART-19 was infused at the dose of 5×10\^6/kg on days 1 to 3 of the first cycle and on day 1 of the second to fourth cycle. The Bayesian optimal design was applied to perform the futility assessment at the specified interim analyses. Thirty-four evaluable subjects were recruited, and all the patients received at least two cycles of ssCART-19 consolidation.