2025 Volume 62 Issue 1 Pages 6-13
Since its approval in Japan more than five years ago, the Japan CAR-T Consortium has developed a database to evaluate real-world outcomes in children and young adults with relapsed or refractory B-ALL treated with tisagenlecleucel. This retrospective registry study, initiated after May 22, 2019, analyzed data from 11 Japanese centers encompassing 42 patients who had received tisagenlecleucel by February 1, 2022.
The analysis revealed that the best overall response rate was 93%. At one year post-infusion, the event-free survival (EFS) and overall survival rates were 56% and 82%, respectively. Notably, 27 (64%) patients had low disease burden (LB), defined as <5% bone marrow (BM) lymphoblasts, upon infusion. LB was associated with significantly better outcomes, with a one-year EFS rate of 80%, compared to 24% in patients with a high disease burden (≥5% BM lymphoblasts) (p<0.0001).
Multivariate analysis indicated that previous hematopoietic stem cell transplantation (HSCT) (n=23, 55%) was linked to improved outcomes, with a hazard ratio of 0.084 (95% CI; 0.02–0.3, p<0.001). Patients who underwent HSCT achieved a one-year EFS rate of 75% compared with 24% in those without previous HSCT.
Extended follow-up and more detailed analyses of patient samples may provide deeper insights into the biology of CAR-T cell therapy and inform strategies for improving outcomes in this patient population.
