Haploidentical Versus Matched Sibling Donor HCT in Racially Diverse Pediatric and AYA Patients with Hematologic Malignancies: A Single-Center Comparison
Researchers at the University of Arizona have found that in racially diverse pediatric and adolescent patients with hematologic malignancies, myeloablative haploidentical transplantation with post-transplant cyclophosphamide delivers survival comparable to matched sibling donor transplantation, with manageable graft-versus-host disease (GVHD), but with higher cytomegalovirus (CMV) reactivation. In a single-center cohort enriched for Hispanic and other minority patients, overall survival and leukemia-free survival did not differ meaningfully between haploidentical and matched sibling approaches, and GVHD–free, relapse-free survival (GRFS) was similarly comparable. Donor age emerged as an independent predictor of chronic GVHD, underscoring its importance when multiple haploidentical relatives are available.
The team retrospectively analyzed 72 patients aged 0 to 28 years who received myeloablative conditioning followed by either T-cell–replete haploidentical transplantation (n=43) using post-transplant cyclophosphamide with or without bendamustine plus tacrolimus and mycophenolate, or matched sibling donor transplantation (n=29) using methotrexate and cyclosporine or post-transplant cyclophosphamide-based prophylaxis. Following two graft failures in early haploidentical cases, increasing fludarabine from 30 to 40 mg/m² eliminated further failures, with both affected patients successfully re-engrafted following a second haploidentical transplant.
Outcomes at median follow-up of 39.4 months for matched sibling and 48.7 months for haploidentical recipients were closely aligned. Overall survival was 74.5 percent versus 70.1 percent (P=.89) and leukemia-free survival 70.6 percent versus 67.8 percent (P=.87). Relapse was 26.8 percent versus 23.0 percent (P=.49) and non-relapse mortality 13.1 percent versus 9.8 percent (P=.95). Severe acute GVHD trended higher with haploidentical transplantation at 19.4 percent versus 7.3 percent (P=.17), while chronic disease trended higher after matched sibling transplantation at 35.9 percent versus 23.9 percent (P=.25). GRFS was similar at 60.1 percent versus 54.1 percent (P=.83). CMV reactivation requiring therapy was higher with haploidentical transplantation at 40 percent versus 7 percent (P=.002). Clinically, these data support haploidentical transplantation as an effective and accessible option when a matched sibling is lacking, particularly in minority populations, while highlighting the need to prioritize younger donors.
Reference:
Filioglou D, Kovacs K, Lafleur BJ, et al. Haploidentical Versus Matched Sibling Donor HCT in Racially Diverse Pediatric and AYA Patients with Hematologic Malignancies: A Single-Center Comparison. Transplant Cell Ther. Published online September 8, 2025.