移植前 MRD 阴性与年龄低于 40 岁预测复发/难治性 B-ALL 经 CAR-T 桥接单倍体 HSCT 后更优的长期生存：一项随访 6 年的多中心回顾性研究

Sequential allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a critical approach to enhance the efficacy of chimeric antigen receptor T cell (CAR-T) therapy for relapsed/refractory acute lymphoblastic leukemia (R/R ALL). The long-term survival rates following allo-HSCT after CAR-T cell therapy remain controversial.

We previously reported the results of 122 patients with R/R B-ALL who achieved minimal residual disease negative (MRD-) complete remission (CR) after anti-CD19 CAR-T, including 67 patients without subsequent transplantation (non-transplant group) and 55 patients with subsequent haplo-HSCT (transplant group).

Here, we present the extended follow-up of this cohort, with a median of 72. 9 months. Compared with the non-transplant group, transplantation recipients had a higher 5-year LFS (50. 5% vs. 25. 7%; p < 0. 001) and OS (53. 5% vs. 25. 6%; p < 0. 001). Multivariable analysis identified MRD positivity at transplantation as an independent factor associated with worse LFS, OS, and a higher cumulative incidence rate of relapse (CIR).

MRD-negative patients before transplant (MRD- group) had a lower 5-year CIR compared to MRD-positive patients (MRD+ group) (20. 8% vs. 50. 0%; p = 0. 014). The 5-year LFS rates in the MRD+ and MRD- groups were 26. 7% and 59. 4%, respectively (p = 0. 003). The 5-year OS of the MRD- group was higher than that of the MRD+ group (62. 0% vs. 30. 5%; p = 0. 006). For patients who achieve CR after CAR-T therapy, haplo-HSCT with pre-transplant MRD negativity was associated with better long-term survival.

However, infections emerged as a significant complication that may reduce the long-term survival benefits. Trial Registration: ClinicalTrials. gov identifier: ChiCTR1900023957.