[Efficacy of CD19 Chimeric Antigen Receptors T Cells in the Treatment of Relapsed Patients with B Cell Acute Lymphoblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation].

OBJECTIVE

To study the long-term efficacy and safety of CD19 chimeric antigen receptor T cells (CAR-T) in the treatment of relapsed patients with B-cell acute lymphoblastic leukemia (ALL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODS

A total of 7 patients with B-cell ALL relapsed after allo-HSCT were treated with CD19 CAR-T cells from September 2015 to March 2018. Among them, 6 had hematological recurrence and 1 had positive of MRD. They all were treated with a single infusion of CAR-T cells. FC chemotherapy regimen was administered before transfusion. The median number of CAR-T cells transfused was 6.0 (range 4.0-8.6) )×106/kg. Long-term efficacy and toxicity were evaluated.

RESULTS

Bone marrow examination performed at d 30 after CAR-T infusion showed that all 7 patients achieved complete remission and MRD negative, grade I CRS for 1 case and grade II CRS for 6 cases, two of them had mild neurotoxicity, which was controlled by treatment. Two patients presented grade VI intestinal GVHD after CAR-T infusion. The median follow-up time was 18 months (range 12-42). Follow-up showed that two patients relapsed at 9 months and 14 months after treatment, out of 2 patients one died of progressive disease and the other reachived the hematological remission, but MRD was positive after CD22 CAR-T cell therapy. At present, five patients are disease-free survival, moreover showed complete donor chimerism. One year after CAR-T cell therapy, the results of immune reconstitution showed that CD4 level was more than 300×106/L in 5 patients who disease-free survived. Among them, 3 patients had poor recovery of immunoglobulin and received gamma globulin replacement therapy.

CONCLUSION

All patients are followed up for at least one year. The preliminary efficacy and safety are satisfactory. CAR-T cell infusion is an effective method for the treatment of B-ALL recurrence after allo-HSCT.