A single-center retrospective study of short-term efficacy and safety of blinatumomab in the treatment of high-risk acute lymphoblastic leukemia.

Treatment outcomes for high-risk B-ALL remain suboptimal. Blinatumomab, a CD19/CD3 bispecific T-cell engager, has shown efficacy in trials, but real-world data in Chinese high-risk patients are limited. This single-center retrospective study analyzed 29 high-risk B-ALL patients treated with blinatumomab (7-28 days/cycle). We assessed short-term efficacy (MRD negativity rate), safety, and the impact of genetic factors and treatment duration. The overall MRD negativity rate after one cycle of blinatumomab was 82.8% (24/29). All patients with the Ph-like subtype (3/3, 100%) and 71.4% (10/14) of Ph+ patients achieved MRD negativity. However, clinical outcomes were inferior in patients harboring specific genetic alterations: 50% (2/4) of patients with the BCR::ABL1 T315I mutation experienced early relapse, and only one of two patients with E2A::PBX1 rearrangement achieved transient MRD negativity. The median event-free survival (EFS) was 9.6 months (95% CI: 6-16.75). Grade ≥ 3 hematologic toxicity occurred in 48.3% (14/29) of the patient cohort. Blinatumomab achieved high short-term MRD response rates in high-risk B-ALL. Inferior outcomes appeared to be associated with the presence of BCR::ABL1 T315I mutations and E2A::PBX1 rearrangements.