Study on Use of CAR-T Cells in Allogeneic Hematopoietic Stem Cell Transplantation

Abstract Background: The chimeric antigen receptor T (CAR-T) cells have showed strong anti-leukemia role, which can treat or prevent relapse by targeting minimal residual disease for patients undergone allogeneic hematopoietic stem cell transplantation (allo-HSCT). The infusion of allogeneic CAR-T cells may cause the graft-versus-host disease, which could limit its use during and after allo-HSCT. It is still unclear whether CAR-T cells can be used during and after allo-HSCT. In this study, the use of CAR-T cells in these situation was explored. Methods: Two patients with relapsed/refractory acute lymphoblastic leukemia (ALL) received allo-HSCT, the CAR-T cells was used as a reduced-intensity conditioning regimen. Another three patients with high-risk ALL received preventive infusion of CAR-T cells on days +60 after allo-HSCT. Results: For patients undergone allo-HSCT, the time of peak CAR-T cell proliferation was detected after the first infusion of CAR-T cells on day 7. The engraftment and full donor cell engraftment were established. The disease was in complete remission with negative minimal residual disease, which was undetectable by flow cytometry. No graft-versus-host disease and serious cytokine release syndrome was found. For patients received preventive infusion of CAR-T cells, the CAR-T cells continually survival. No graft-versus-host disease and serious cytokine release syndrome was found. The disease is complete remission for 1-6 months. Conclusion: It is safety and effective for CAR-T cells used in allogeneic hematopoietic stem cell transplantation. Disclosures No relevant conflicts of interest to declare.