Outcomes of Haploidentical Stem Cell Transplantation for Acute Lymphoblastic Leukemia Patients: A Single-Center Experience in Mexico.

Access to allogeneic hematopoietic stem cell transplantation (allo-HSCT) for acute lymphoblastic leukemia (ALL) remains limited in low- and middle-income countries (LMICs). Haploidentical stem cell transplantation (haplo-SCT) with post-transplant cyclophosphamide (PTCy) has expanded donor availability, but data from Latin America are scarce. To evaluate clinical outcomes of haplo-SCT in pediatric and adult ALL patients in a single center in Mexico using a standardized protocol. This retrospective observational study included 28 MRD-negative patients with ALL who received haplo-SCT at Centro Médico ABC between 2019 and 2023. Conditioning regimens include total body irradiation, cyclophosphamide, and etoposide. PTCy-based GVHD prophylaxis was used in all cases. Outcomes included overall survival (OS), event-free survival (EFS), GVHD incidence, and transplant-related complications. The median age was 9 yr (range: 1 to 55); 82% were pediatric and 18% were adult. Blinatumomab was used in 36% of patients prior to transplant; all Ph+ cases received tyrosine kinase inhibitors. The 60-month OS was 64.1% (95% CI, 53.8% to 74.4%) and EFS was 55.6% (95% CI, 44.6% to 66.6%). Neutrophil engraftment occurred in 96.4% of patients. Acute GVHD occurred in 54% and chronic GVHD in 32%. Nonrelapse mortality at 100 d was 7%. No cases of cytokine release syndrome were observed. This study demonstrates that haplo-SCT using modern protocols yields favorable outcomes in a resource-limited Mexican setting, supporting its broader adoption in LMICs. Long-term survival was comparable to outcomes reported in high-income countries, highlighting the feasibility and scalability of this strategy.