Objectives: The objective of the study is to describe the feasibility, toxicity, and early transplant outcomes of a structured resource-adapted immunotherapy bridging program using blinatumomab and/or inotuzumab ozogamicin (InO) to achieve measurable residual disease (MRD)-negative status before allogeneic hematopoietic stem cell transplantation (allo-HSCT) in high-risk acute lymphoblastic leukemia (ALL). Material and Methods: This was a retrospective single-center analysis of consecutive high-risk patients with ALL who underwent allo-HSCT between December 2023 and September 2025 (data cutoff: December 14, 2025). Bridging feasibility measures were predefined. Blinatumomab was delivered using a label-supported multi-day infusion with the 7-day bag option, prepared with bacteriostatic 0.9% sodium chloride under pharmacy-supervised aseptic conditions in eligible patients, and age-adapted step-up dosing was used. InO was dose-capped at 0.3 mg/m 2 /dose, same-day scheduling was used, when possible, to facilitate vial sharing, and a planned washout of at least 6 weeks was maintained before allo-HSCT to mitigate sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) risk. End points included feasibility, blinatumomab utilization, toxicity, relapse, overall survival (OS), leukemia-free survival (LFS), non-relapse mortality (NRM), SOS/VOD, transplant-associated thrombotic microangiopathy (TMA), and graft failure. Results: Nine patients underwent allo-HSCT after MRD-negative bridging. Donors were haplo-identical related in 7 patients and matched siblings in 2. Blinatumomab was used in 6/9 patients (1 cycle in 5; 2 cycles in 1) and InO in 4/9 patients (3 doses each; dose-capped). One multiply relapsed Philadelphia chromosome-positive patient after CAR-T therapy received ponatinib plus asciminib plus InO before transplantation. Median blinatumomab utilization was 14.5 vials/cycle (38.5 mg), range 6–16. All blinatumomab recipients developed grade 1 cytokine release syndrome, and 1 patient developed grade 3 immune effector cell-associated neurotoxicity syndrome with seizure. At the cutoff, relapse occurred in 2/9 patients, with 1 death after relapse. The estimated 1-year Kaplan– Meier OS was 100%, and the estimated 1-year Kaplan–Meier LFS was 70%. NRM, SOS/VOD, and graft failure were each 0%, and TMA occurred in 1/9 patients. Conclusion: A structured feasibility-focused bridging program combining label-supported 7-day blinatumomab infusion bags, age-adapted step-up dosing, and dose-capped InO with vial sharing and a transplant washout strategy enabled MRD-negative allo-HSCT in all transplanted patients in this small real-world high-risk ALL cohort. The approach showed encouraging early survival with no NRM or SOS/VOD and supports prospective evaluation of resource-conscious immunotherapy implementation in transplant-eligible ALL.
Mehta et al. (Sat,) studied this question.