Abstract 643: Efficacy and safety comparison of CAR-T and blinatumomab immunotherapy as bridge-to-transplant strategy in relapsed/refractory B cell acute lymphoblastic leukemia

Background: B cell acute lymphoblastic leukemia (B-ALL) remains a therapeutic challenge despite advances. Hematopoietic stem cell transplantation (HSCT) provides a potential cure but is hindered by various limitations. Emerging immunotherapies, including chimeric antigen receptor T cell (CAR-T) therapy and Blinatumomab, have shown potential as bridging strategies to HSCT in relapsed/refractory (R/R) cases. Methods: A retrospective study was conducted at Tongji Hospital from March 2017 to March 2023, involving 36 R/R B-ALL patients who underwent HSCT. Prior to transplantation, 27 patients received CD19/CD22 CAR-T therapy, while 9 received Blinatumomab. Outcomes assessed included the overall survival (OS), progression-free survival (PFS), graft-versus-host disease-free and relapse-free survival (GRFS), and non-relapse mortality (NRM), with comparisons made between treatment groups. Hematopoietic reconstitution and transplant-related complications were also evaluated. Results: The median follow-up time was 28.07 (range: 2.29-92.21) months. The 2-year OS, PFS, GRFS, and NRM of the entire cohort were 76.54%, 54.97%, 40.12%, and 9.93%, respectively. In the CAR-T and the Blinatumomab treatment group before transplantation, the 2-year OS was 73.89% and 88.89% (P=0.862), PFS, was 59.03% and 44.44% (P=0.501), GRFS was 47.86% and 13.89% (P=0.083), and NRM was 8.52% and 11.11% (P=0.713), respectively. Safety profiles were similar with no significant differences observed in hematopoietic reconstitution, infection, the incidence of grade II-IV acute graft-versus-host disease (GVHD) and chronic GVHD incidence between CAR-T and Blinatumomab groups. Conclusion: CAR-T and Blinatumomab therapies demonstrate comparable safety and efficacy as bridging treatments to HSCT in patients with R/R B-ALL. Further studies are needed to optimize these treatment strategies. Citation Format: Wenyue Cao, Ningwen Li, Na Wang, Yang Cao. Efficacy and safety comparison of CAR-T and blinatumomab immunotherapy as bridge-to-transplant strategy in relapsed/refractory B cell acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 643.