Effectiveness and Safety of Blinatumomab and Donor Lymphocyte Infusion in Maintenance Therapy After Allogeneic Hematopoietic Stem Cell Transplantation for High-risk Ph Negative B Cell Acute Lymphoblastic Leukemia：Phrase II, Exploratory Study
A single-arm trial to evaluate the effectiveness and safety of Blinatumomab and Donor Lymphocyte Infusion in maintenance therapy after allogeneic hematopoietic stem cell transplantation for high-risk Ph negative B cell acute lymphoblastic leukemia
• Age 14-65 years (inclusive), regardless of gender.
• Newly diagnosed B-ALL with CD19 expression on leukemic cells (regardless of CD19 positivity rate).
• Ph-negative B-ALL with high-risk features post-allo-HSCT .
• ≥2 months post-transplant with hematopoietic reconstitution.
• Bone marrow morphology in remission and MRD-negative before enrollment.
• ECOG performance status \<3 and Karnofsky score ≥70.
• No history of grade III/IV graft-versus-host disease (GVHD) and no active GVHD at enrollment.
• Adequate organ function:AST and ALT ≤3× upper limit of normal (ULN), total bilirubin ≤2×ULN.Serum creatinine ≤2×ULN or creatinine clearance ≥50 mL/min (calculated by Cockcroft-Gault formula).Left ventricular ejection fraction (LVEF) ≥50% by echocardiography (ECHO).
• Expected survival \>3 months.
⁃ Voluntary provision of written informed consent, with ability to understand and comply with study requirements.