Real-World Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation for Acute Lymphoblastic Leukemia: A Single-Center Experience from a Low- and Middle-Income Country

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the principal curative option for patients with high-risk or relapsed acute lymphoblastic leukemia (ALL), particularly in low- and middle-income countries (LMICs) where access to novel immunotherapies, including CAR-T cell therapy, remains limited. Real-world data on allogeneic HSCT outcomes from LMICs remains limited. This retrospective, observational, single-center study aimed to evaluate the efficacy and safety of allogeneic HSCT for ALL in a resource-limited setting. The study was conducted at the Armed Forces Bone Marrow Transplant Centre, Rawalpindi, Pakistan, following approval from the institutional review committee. Medical records of patients with ALL who underwent allo-HSCT were reviewed. Data collected include patient demographics, disease characteristics, transplant details i.e conditioning regimens, donor type, engraftment status, complications, and survival outcomes. Overall survival (OS), disease-free survival (DFS), non-relapse mortality (NRM), and graft-versus-host disease (GVHD) were analyzed. Statistical analyses were performed using SPSS version 25.0. From Jan 2004 till Aug 2025, a total of 101 patients with ALL underwent allo-HSCT. The median age at transplant was 24 years (range, 4-56 years). HCT-CI score of all patients was between 0-2. Disease characteristics and HSCT details are shown in Table 1. Primary graft failure was in 1.01% (n=1) patient. Median time to neutrophil and platelet engraftment was 13 and 21 days respectively. Post allo-HSCT Febrile neutropenia, Hemorrhagic cystitis, Mucositis grade II/III, VOD and TA-TMA was observed in 56.5%, 18.1%, 32.2%,5.1% and 6.3% patients. The cumulative incidence of acute GVHD (grade III–IV) was 22.8% (n=23), and chronic extensive GVHD occurred in 4.1% (n=5) of patients. Non-Relapse Mortality (including infections, GVHD and all-cause mortality) was 39.6% (n=40). In a univariate analysis, the overall survival (OS) for the pediatric group (1–12 years) and adult group was 36% and 44.7%, respectively. For matched sibling and haploidentical donors, the OS was 44.2% and 30.8%, respectively (p=0.2). At a median follow-up of 14 months (range, 1-193 months), OS was 42.6%, and disease-free survival (DFS) was 37.6%. For High risk and relapsed ALL, allo-HSCT remains an effective and feasible curative approach even within the constraints of a low- and middle-income setting.