Acute Lymphoid Leukemia (ALL)

The purpose of this clinical trial is to compare drug combinations to learn which drugs work best to prevent graft-versus-host-disease (GVHD) in people who have received a stem cell transplant. The source of stem cells is from someone who is not related and has a different blood cell type than the study participant. The researchers will compare the new drug combination to a standard drug combination. They will also learn about the safety of each drug combination. Participants will: * Receive the standard or new drug combination after transplant * Visit the doctor's office for check-ups and tests after transplant that are routine for most transplant patients * Take surveys about physical and emotional well-being * Give blood and stool samples.

This single-arm, prospective, multicenter, phase II study will enroll newly diagnosed Philadelphia chromosome-negative (Ph-) acute B-cell lymphoblastic leukemia (B-ALL) patients aged 18-60 years. Participants will receive sequential low-intensity chemotherapy followed by a two-week blinatumomab induction therapy. Treatment Protocol 1. Low-intensity chemotherapy (VIP regimen) * V (Vincristine): 1.4 mg/m² (max 2 mg) on days 1 and 8. * I (Idarubicin): 8 mg/m²/day on days 1 and 8. * P (Prednisone): 60 mg/m²/day (max 100 mg/day) or equivalent dexamethasone dose on days 1-14. 2. Sequential induction therapy: * Blinatumomab administered for 2 weeks following the VIP regimen. 3. Consolidation therapy for morphological complete remission (CR) * Patients achieving CR receive two cycles of consolidation chemotherapy: * Cycle 1: VDCP regimen (Vincristine, Daunorubicin, Cyclophosphamide, Prednisone). * Cycle 2: VP + HD-MTX regimen (Vincristine, Prednisone + High-Dose Methotrexate). 4. Allogeneic hematopoietic stem cell transplantation (allo-HSCT): * Patients with multiparameter flow cytometry-confirmed minimal residual disease (MRD)-negative status proceed to allo-HSCT. Patients achieving morphological complete remission (CR) will undergo two cycles of consolidation chemotherapy. Those with minimal residual disease (MRD)-negative status confirmed by multiparameter flow cytometry (MFC) or next-generation sequencing (NGS) will proceed to allogeneic hematopoietic stem cell transplantation (allo-HSCT). The primary endpoint is 18-month relapse-free survival (RFS) rate, the secondary endpoints were composite response rate (CRc: CR + CR with incomplete hematologic recovery \[CRi\]), MRD-negative rate (assessed by MFC/NGS),18-month overall survival (OS) post-transplant, non-relapse mortality (NRM), cumulative incidence of acute/chronic graft-versus-host disease (GVHD), cumulative relapse rate and 18-month GVHD-free/relapse-free survival (GRFS) post-transplant.