Westudied 1110 patients with b-thalassemia major aged ≤25 years who received transplants with grafts from HLA-matched related (n 5 677; 61%), HLA-mismatched related (n 5 78; 7%), HLA-matched unrelated (n 5 252; 23%), and HLA-mismatched unrelated (n 5 103; 9%) donors between 2000 and 2016. Ninety percent of transplants were performed in the last decade. Eight-five percent of patients received ≥20 transfusions and 88% were inadequately chelated. All patients received myeloablative-conditioning regimen. Overall and event-free survival were highest for patients aged ≤6 years and after HLA-matched related and HLA-matched unrelated donor transplantation. The 5-year probabilities of overall survival for patients aged ≤6 years, 7 to 15 years, and 16 to 25 years, adjusted for donor type and conditioning regimen were 90%, 84%, and 63%, respectively (P <001). The corresponding probabilities for event-free survival were 86%, 80%, and 63% (P <.001). Overall and eventfree survival did not differ between HLA-matched related and HLA-matched unrelated donor transplantation (89% vs 87% and 86% vs 82%, respectively). Corresponding probabilities after mismatched related and mismatched unrelated donor transplantation were 73% vs 83% and 70% vs 78%. In conclusion, if transplantation is considered as a treatment option it should be offered early (age ≤6 years). An HLA-matched unrelated donor is a suitable alternative if an HLA-matched relative is not available.
Bibliographical noteFunding Information:
The Center for International Blood and Marrow Transplant Research was supported by U24-CA76518 from the National Institutes of Health, National Cancer Institute, National Heart, Lung, and Blood Institute, and National Institute of Allergy and Infectious Diseases, and HHSH 250201200016C from the Health Services Research Administration, Department of Health and Human Services.