Outcomes of Delayed HLA Haploidentical Transplantation with Peripheral Blood Allografts for High-Risk Patients with Severe Aplastic Anemia

Abstract

Background: In severe aplastic anemia (AA) sibling haploidentical hematopoietic stem cell transplantation (haplo-HSCT) from the peripheral blood (PB) is an alternative when an HLA-identical donor is unavailable. Objective: To document the results of haplo-HSCT in high-risk severe AA. Methods: Twelve patients with severe AA who failed medical therapy and received a haploidentical PB unmanipulated HSCT from a sibling at an academic medical center were analyzed. Overall (OS) and event-free survival (EFS) were determined by Kaplan-Meier analyses. Results: The median between AA diagnosis and haplo-HSCT was 6.5 months (2-19). Median of age was 25.5 (range, 4-54) years; 9 (75%) recipients were males, and all suffered multiple treatment failures. Anti-thymocyte globulin-based conditioning regimens were given to 6 (50%) patients. Five (41.7%) HSCT were ambulatory. Infections developed in all patients and graft failure in 9 (75%). 2-year OS was 52% and EFS 25%. High transfusion burden, treatment failure, and donors > 30 years had no effect on OS (p = 0.518, p = 0.984, p = 0.321) or EFS (p = 0.113, p = 0.692, p = 0.199). Patient's age > 40 was not significant for survival (p = 0.395). Three of five evaluable patients developed acute graft-versus-host disease that progressed to chronic disease. Conclusions: Delayed PB haplo-HSCT for severe AA offered poor outcomes. Rapid referral for HSCT is critically required. (Rev Invest Clin. 2025;77(1):26-33).

Keywords: Anti-thymocyte globulin; Haploidentical transplant; Hematopoietic stem cell transplant; Outpatient hematopoietic stem cell transplantation; Peripheral blood transplant; Severe aplastic anemia.