Efficacy and Safety of CAR-T Cell Therapy in Relapsed/Refractory B-Cell Acute Lymphoblastic Leukemia With Central Nervous System Involvement.

Central nervous system (CNS) involvement in B-cell acute lymphoblastic leukemia (B-ALL) is associated with relapse, treatment refractoriness, and poor prognosis. Although chimeric antigen receptor (CAR) T cell therapy has demonstrated remarkable efficacy in relapsed/refractory (R/R) B-ALL, its efficacy and safety in CNS leukemia (CNSL) remain unclear. We retrospectively analyzed 113 R/R B-ALL patients who received CAR-T cell therapy, stratifying them into CNS-positive (n = 22) and CNS-negative (n = 91) groups based on the presence of CNSL prior to infusion. At Day 28 after CAR-T infusion, the overall complete remission (CR) rate was 81.8%, with no significant difference between groups. The incidence of cytokine release syndrome (CRS) and neurotoxicity was comparable. The 3-year cumulative incidence of relapse (CIR), event-free survival (EFS), and overall survival (OS) were similar between groups. However, CNSL patients exhibit a higher cumulative relapse rate following CAR-T-induced remission, with an increased risk of CNS relapse compared to patients without CNS involvement. Multivariate analysis identified allo-HSCT as consolidation post-CAR-T as an independent protective factor for improved EFS and OS in CNSL patients. In conclusion, CAR-T therapy offers similar efficacy and safety in R/R B-ALL patients regardless of CNS involvement. Furthermore, CAR-T cell therapy was not sufficient to maintain sustained remission, and consolidative allo-HSCT may improve long-term survival in this high-risk group.