Bridging With Chimeric Antigen Receptor T‐Cell Therapy or Chemotherapy to Allo‐ HSCT in B‐ ALL : A Comparison of Treatment Complications and Survival

OBJECTIVES: Comparisons of safety and efficacy of Allogeneic hematopoietic stem cell transplantation (allo-HSCT) following complete remission (CR) achieved by Chimeric antigen receptor T (CAR-T) cell therapy versus chemotherapy for B-cell acute lymphoblastic leukemia (B-ALL) have not been fully discussed. METHODS: We performed a comparison of transplant outcomes in 443 consecutive B-ALL patients who received allo-HSCT after achieving CR with CAR-T therapy (n = 50) or with chemotherapy (n = 393). The median follow-up time was 30 months (range: 1-62 months). RESULTS: The CAR-T group had a lower incidence of chronic graft-versus-host disease (30.9% vs. 44.0%, p = 0.020). We also found that the incidence of veno-occlusive disease was higher in the CAR-T group compared to the chemotherapy group (4% vs. 0.5%; p = 0.003). The study revealed that both the CAR-T and chemotherapy groups exhibited comparable overall survival (90.9% vs. 94.6%, p = 0.158) and relapse incidences (9.1% vs. 8.4%, p = 0.513). However, incidences of non-relapse mortality after transplantation were higher in the CAR-T group (10.9% vs. 4.3%, p = 0.016), and leukemia-free survival was lower in the CAR-T group compared to the chemotherapy group (80.0% vs. 86.8%, p = 0.040). CONCLUSIONS: Our data indicate that, in B-ALL patients, most treatment-related complications and survival were comparable between CAR T-cell therapy and chemotherapy followed by allo-HSCT.