Background:

Maintaining the efficacy of anti-CD19 chimeric antigen receptor modified (CAR) T-cell therapy in patients with B-cell acute lymphoblastic leukemia (B-ALL) relapsed after transplantation is an urgent problem.

Methods:

: Overall 22 B-ALL patients who relapsed after allogenic hematopoietic stem cell transplantation (allo-HSCT) received anti-CD19-CAR T-cell therapy. Patients who responded to CAR-T cell therapy received donor hematopoietic stem cell infusion (DSI) or donor lymphocyte infusion (DLI) as maintenance therapy. We compared the clinical responses, acute graft versus host disease (aGVHD), expansion of CAR-T cells, and adverse events between two groups.

Results:

: CR or CR with incomplete count recovery was achieved in 19 patients (86.4%). After DSI/DLI therapy, grade I-II of aGVHD was observed in 4 patients (36.4%) in DSI group. Only one patient developed grade II aGVHD in DLI group. The peaks of CAR T-cells in DSI group were higher than in DLI group. IL-6 and TNF-α levels increased again in 9 of 11 patients after DSI but not in DLI group. Progression-free survival and overall survival were higher in DSI group than in DLI group at 365 days.

Conclusions:

: For B-ALL patients who relapsed after allo-HSCT, DSI is a feasible maintenance therapy if CR is obtained with CAR-T cell therapy. Trial registration: ChiCTR-ONN-16009862 Registered14November2016,https://www.chictr.org.cn/showproj.aspx?proj=16756 ChiCTR1800019622 Registered24November2018,https://www.chictr.org.cn/showproj.aspx?proj=33185