Impact of Low-intensity Chemotherapy Combined With Short-course Blinatumomab on Allo-HSCT in Adults With Ph- B-ALL

Inclusion criteria

Patients (Age 18-60 years ) with an ECOG performance status of 0-2 and HCT-CI score <3.

• Diagnosis: Confirmed Philadelphia chromosome-negative (Ph-) acute B-cell lymphoblastic leukemia (B-ALL) by:

• Bone marrow morphology
• Cytochemistry
• Immunophenotyping (CD19-positive by flow cytometry, ≥20% positivity on leukemic cells)
• Chromosomal analysis
• Molecular/genetic testing. 3. Planned allo-HSCT candidates must have an eligible hematopoietic stem cell donor, including:
• HLA-matched sibling donors
• Unrelated donors (9/10 or 10/10 HLA allele-matched by high-resolution typing)
• Haploidentical related donors. 4. No significant organ dysfunction:
• Liver: ALT/AST ≤3× upper limit of normal (ULN); total bilirubin ≤2× ULN.
• Kidney: BUN and serum creatinine ≤1.25× ULN.
• Cardiac:
• No acute myocardial infarction or severe arrhythmia on ECG.
• Left ventricular ejection fraction (LVEF) ≥50% on echocardiography; no significant cardiomegaly, valvular disease, or congenital heart defects.
• Pulmonary: FEV1, FVC, and DLCO ≥60% of predicted values. 5. Contraception:
• Men, women of childbearing potential (postmenopausal women must be amenorrheic for ≥12 months), and their partners must use investigator-approved effective contraception during treatment and for ≥12 months after the last study intervention.

• Informed consent: Patients and their legal guardians must provide written informed consent, demonstrate willingness to undergo allo-HSCT, and agree to comply with treatment protocols, follow-up schedules, and laboratory tests.

Exclusion criteria

• Non-de novo patients(i.e., relapsed/refractory disease).
• BCR-ABL1 fusion gene-positive (Ph+ ALL confirmed by molecular testing).
• Uncontrolled active infections or viral diseases:

• Active bacterial, viral, or fungal infections requiring treatment.
• Hepatitis B: HBsAg-positive or HBcAb-positive with detectable HBV DNA in peripheral blood.
• Hepatitis C: HCV antibody-positive with detectable HCV RNA.
• Syphilis: Positive TRUST test.
• HIV: HIV antibody-positive.
• Major organ dysfunction or comorbidities:

• Cardiovascular:
• Uncontrolled hypertension, hypertensive crisis, or encephalopathy.
• History of congestive heart failure (CHF), unstable angina, clinically significant arrhythmias (e.g., ventricular fibrillation, ventricular tachycardia).
• Arterial thrombosis within 3 months (e.g., stroke, transient ischemic attack).
• Symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) within 6 months.
• Coronary angioplasty, defibrillation, or other high-risk cardiovascular procedures.
• Pulmonary: Severe respiratory insufficiency.
• Gastrointestinal: Active bleeding within 3 months.
• Uncontrolled concurrent illnesses that may compromise safety or study integrity.
• Active or untreated central nervous system (CNS) involvement (e.g., CNS leukemia, epilepsy requiring therapy).
• Pregnancy, lactation, or plans for pregnancy within 1 year post-infusion or during the study period.
• Uncontrolled active infections (excluding uncomplicated UTIs or upper respiratory infections).
• Hypersensitivity to blinatumomab or its components.
• Inability to provide informed consent or comply with study procedures.
• Investigator discretion: Any condition deemed to jeopardize patient safety or interfere with study objectives.