Pretransplant Blinatumomab Is Associated With Reduced Relapse and Improved Disease-Free Survival in Adults With B-Cell ALL Undergoing Allogeneic Hematopoietic Cell Transplantation.

BACKGROUND

Adults with B-cell acute lymphoblastic leukemia (B-ALL) have inferior survival compared with pediatric patients, and pretransplant measurable residual disease (MRD) predicts relapse after allogeneic hematopoietic stem cell transplantation (HSCT). Blinatumomab, a bispecific CD3/CD19 antibody, may eradicate MRD, but its pretransplant impact is unclear.

OBJECTIVES

To evaluate the effect of pretransplant blinatumomab on survival, relapse, graft-versus-host disease (GVHD), and GVHD-free, relapse-free survival (GRFS) in this single-center retrospective cohort adult B-ALL patients.

PATIENTS AND

METHODS

This single-center retrospective study included 145 predominantly Hispanic adults (≥18 years) with B-ALL who underwent HSCT between 2013 and 2025, with 56 receiving pretransplant blinatumomab and 89 controls. Outcomes were overall survival (OS), disease-free survival (DFS), cumulative incidence of relapse (CIR), non-relapse mortality (NRM), GRFS, and grade III/IV acute and severe chronic GVHD.

RESULTS

Among 145 adults (median age 42 years), 76.6% were Hispanic and 38.6% received pretransplant blinatumomab. The 2-year OS and DFS for the cohort were 88.6% and 70.3%, respectively. Blinatumomab was associated with improved 2-year DFS (84.4% vs. 62.8%; HR 0.45; 95% CI, 0.21-0.97; P = .042) and reduced CIR (7.4% vs. 31.0%; HR 0.27; 95% CI, 0.09-0.77; P = .014) on univariate analysis. These benefits persisted on multivariate analysis adjusting for disease stage, cytogenetics, and MRD status (DFS: HR = 0.34; 95% CI, 0.15-0.80; P = .014; CIR: HR = 0.26; 95% CI, 0.09-0.74; P = .012). NRM, GRFS, and grade III/IV acute and severe chronic GVHD did not differ.

CONCLUSION

In this predominantly Hispanic adult B-ALL population, pretransplant blinatumomab safely reduces relapse risk and improves disease-free survival without increasing post-transplant toxicity.