Long-term post-transplant outcomes after peri‑transplant blinatumomab in chemotherapy-refractory pH-negative B-ALL: A real-world Japanese single-center case series

Background Chemotherapy-refractory Philadelphia chromosome–negative B-cell acute lymphoblastic leukemia in adults who are ineligible for clinical trials remains difficult to cure, and real-world data on peri‑transplant blinatumomab in Japanese adults are scarce. Methods: We conducted a single-center retrospective series of consecutive adult Japanese patients with chemotherapy-refractory, Philadelphia chromosome–negative B-cell acute lymphoblastic leukemia who received peri‑transplant blinatumomab between 2019 and 2025. Results: Three trial-ineligible patients received blinatumomab as a bridge to allogeneic hematopoietic cell transplantation, with one also receiving post-transplant blinatumomab; all achieved complete remission, two attained pre-transplant minimal residual disease negativity, and all remain in continuous remission at 18, 57, and 76 months without relapse, graft failure, chronic graft-versus-host disease, or transplant-related mortality. Conclusions: Peri-transplant blinatumomab appears feasible in this setting and was associated with durable post-transplant remission and a favorable safety profile.