Post-HSCT relapsed precursor B-cell ALL successfully salvaged by BiTE followed by consolidation CAR-T cell therapy: A report of two cases.

Precursor B-cell acute lymphoblastic leukemia (pre-B ALL) relapse after allogeneic hematopoietic stem cell transplantation (HSCT) typically has poor outcomes. Both bispecific T-cell engager (BiTE, blinatumomab) and chimeric antigen receptor T-cell (CAR-T) are novel immuno-designed therapies for advanced acute lymphoblastic leukemia. However, the treatment and effects of their combination remain unclear. Two patients with pre-B ALL experienced overt leukemic relapse after allogeneic HSCT. Both patients received one standard cycle of blinatumomab treatment, and complete remission was achieved. Subsequently, during remission, both patients underwent treatment with CAR-T cells prepared from their own T-cells. One patient received CD22-CAR-T cell as a consolidative therapy, while the other underwent CD19-CAR-T cell therapy. No cytokine release syndrome occurred. After treatment, both patients are alive and do not have leukemia recurrence for more than one year. In conclusion, sequential combination of BiTE followed by CAR-T cell therapy may show promising results for relapsed and advanced B-cell leukemia. This novel combination is worthy of further investigation.