Among patients undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT) for B cell acute lymphoblastic leukemia (B-ALL), pretransplant chemotherapy may yield similar survival outcomes to those seen with chimeric antigen receptor (CAR)T-cell therapy, according to research published in Frontiers in Immunology.

Among patients with relapsed/refractory B-ALL, allo-HSCT is frequently used to improve clinical outcomes. Reaching a complete response (CR) prior to allo-HSCT, furthermore, is linked with greater odds of survival in this patient population.

Recent research suggests that up to 90% of patients undergoing CAR T cell therapy prior to allo-HSCT may reach a CR. There is, however, evidence that post-allo-HSCT outcomes are not optimal after CAR T cell therapy, suggesting that comparative trials are needed. For this study, researchers evaluated post-transplantation outcomes among patients with B-ALL undergoing chemotherapy or CAR-T cell therapy prior to allo-HSCT.

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Overall, data from 105 patients were included, of whom 27 had reached a CR with CAR T cell therapy and 78 had reached a CR with chemotherapy. The median patient age was 13 years, 58% of patients were male, and 53% of patients were considered pediatric.

More patients in the CAR T group were in at least a second CR (78% vs 37% in the chemotherapy group; P <.01); these patients were also more likely to have complex cytogenetics (44% in the CAR T group vs 6% in the chemotherapy group; P <.001). The rates of minimal residual disease were, however, similar between the groups.

The overall median follow-up time was 49 months. Patients who underwent CAR T cell therapy were more likely to develop grade 2-4 acute graft-vs-host disease (48.1% vs 25.6% with chemotherapy; P =.016), but not chronic graft-vs-host disease (73.3% vs 55%; P =.107).

The cumulative incidence of relapse was 11.1% in the CAR T group vs 12.8% in the chemotherapy group (P =.84); the cumulative incidence of non-relapse mortality (18.7% vs 23.1%, respectively; P =.641), leukemia-free survival (70.2% vs 64.1%; P =.63), and overall survival (70.2% vs 65.4%; P =.681) similarly, did not differ between the 2 groups.


Zhao YL, Liu DY, Sun RJ, et al. Integrating CAR T-cell therapy and transplantation: comparisons of safety and long-term efficacy of allogeneic hematopoietic stem cell transplantation after CAR T-cell or chemotherapy-based complete remission in B-cell acute lymphoblastic leukemia. Front Immunol. 2021;12:605766. 10.3389/fimmu.2021.605766