Overview
This is a single arm, open-label, single-center, phase I/II study to determine the safety and efficacy of CD19 CAR-T( ssCART-19) combined with feeding T cells (FTCs) as consolidation therapy in patients diagnosed with de novo Philadelphia chromosome positive CD19+ B-ALL. The study will contain the following sequential phases: screening, lymphocyte apheresis, induction and consolidation chemotherapies combined with tyrosine kinase inhibitors. Once in complete response, patients will receive four cycles of ssCART-19s, namely one cycle of ssCART-19 infusion followed by another three cycles of ssCART-19 and FTC infusion. The role of FTCs is to mimic leukemia cells. Therefore, they are expected to stimulate in vivo expansion and persistence of ssCART-19. Considering the limited number of lymphocytes obtained by a single apheresis from patients and cost-efficacy, in addition to safety, we will explore the range of biologically active doses of FTCs in a phase I study. Based on preclinical data, FTCs stimulation of ssCART-19 at a ratio of 1:1 could achieve the best activation response, so 5×106/kg dosage of FTCs was set as the initial dosage in the study, and lower dose was also evaluated. In this study, FTCs will be administered at the dose of 5×106/kg, 3.25×106/kg or 2×106/kg two hours after ssCART-19 infusion on day 1 and once again administered at the same dose on day 8. After ssCART-19 and FTCs infusion, efficacy will be assessed by detecting molecular response for 6 months, PFS and OS will be followed up for 2 years. In phase II, we will expand the study at optimal biological doses of FTCs, and further evaluate the efficacy and safety of the innovative combination therapy of CD19 CAR-T and FTCs.
Eligibility
Inclusion Criteria:
- Ph+ acute B-lymphoblastic leukemia patients having received once CD19 CAR-T therapy
- continuously taking TKI medications
- no chance to receive allogeneic hematopoietic stem cell transplantation
- no severe complications
- ECOG score less than 3
Exclusion Criteria:
- Detection of mutations on abl gene
- resistance to TKI medications