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

ABSTRACT 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.