Comparative Outcomes between Haploidentical and HLA-Identical Related Hematopoietic Stem Cell Transplantation in a Reference Hematology Center in Northeastern Mexico.

Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for several hematologic malignancies and bone marrow failure syndromes. Donor availability remains a critical factor influencing access to HSCT, particularly in low- and middle-income countries where unrelated donor registries are scarce. Haploidentical HSCT using post-transplant cyclophosphamide (PTCy) has expanded donor options and improved accessibility, but comparative data from Latin American centers are still underreported. We performed a retrospective cohort study including all consecutive patients who underwent allogeneic HSCT between January 2020 and December 2024 at a tertiary hematology referral center in northeastern Mexico. Clinical and transplant-related variables were analyzed, including diagnosis, donor type, CD34+ cell dose, and early mortality (30 and 100 days). Survival outcomes included overall survival (OS) and relapse-free survival (RFS) were estimated using Kaplan-Meier and compared with the log-rank test (p < 0.05). Conditioning regimens were based on CyFlu plus melphalan ± TBI or busulfan; GVHD prophylaxis included PTCy, a calcineurin inhibitor, and mycophenolate mofetil. Among 190 transplanted patients (mean age 34.8 ± 16 years; 62.6% male), diagnoses included ALL (34.7%), AML (34.7%), aplastic anemia (14.7%), MDS (5.3%), lymphomas (7.9%), and others (2.7%). Haploidentical donors were used in 65.3% and HLA-identical donors in 34.7%. The median infused CD34+ cell dose was 9.9 × 10⁶/kg, with a median follow-up of 288 days. Early post-transplant mortality was low, with 30-day mortality rates of 6.1% in the haploidentical group and 4.5% in the identical group, and 100-day mortality of 14.5% and 13.6%, respectively. One-year OS was 68.1% for haploidentical and 79.7% for identical HSCT (p = 0.153), while RFS was 84.7% vs 81.2% (p = 0.438)(Figure 1). Subgroup analysis showed higher OS in aplastic anemia for identical HSCT (p = 0.003) and superior RFS in AML/MDS for haploidentical HSCT (p = 0.045). The incidence of grade III–IV acute GVHD was 9.1% in identical and 12.1% in haploidentical transplants, while moderate to severe chronic GVHD occurred in 12.1% and 21.0%, respectively; neither form of GVHD significantly affected overall or relapse-free survival. Haploidentical HSCT achieved survival outcomes comparable to HLA-identical transplants, validating its role as an effective alternative when matched donors are unavailable. Disease-specific trends suggest identical HSCT remains preferable for aplastic anemia, while haploidentical strategies may offer enhanced relapse control in myeloid neoplasms. These findings support haploidentical HSCT as a feasible, cost-effective approach for expanding transplant access in resource-limited regions.