Allogeneic Hematopoietic Cell Transplantation in Patients Aged 50 Years or Older with Severe Aplastic Anemia

We report on 499 patients with severe aplastic anemia aged ≥ 50 years who underwent hematopoietic cell transplantation (HCT) from HLA-matched sibling (n = 275, 55%) or HLA-matched (8/8) unrelated donors (n = 187, 37%) between 2005 and 2016. The median age at HCT was 57.8 years; 16% of patients were 65 to 77 years old. Multivariable analysis confirmed higher mortality risks for patients with performance score less than 90% (hazard ratio [HR], 1.41; 95% confidence interval [CI], 1.03 to 1.92; P =.03) and after unrelated donor transplantation (HR, 1.47; 95% CI, 1 to 2.16; P =.05). The 3-year probabilities of survival for patients with performance scores of 90 to 100 and less than 90 after HLA-matched sibling transplant were 66% (range, 57% to 75%) and 57% (range, 47% to 76%), respectively. The corresponding probabilities after HLA-matched unrelated donor transplantation were 57% (range, 48% to 67%) and 48% (range, 36% to 59%). Age at transplantation was not associated with survival, but grades II to IV acute graft-versus-host disease (GVHD) risks were higher for patients aged 65 years or older (subdistribution HR [sHR], 1.7; 95% confidence interval, 1.07 to 2.72; P =.026). Chronic GVHD was lower with the GVHD prophylaxis regimens calcineurin inhibitor (CNI) + methotrexate (sHR,.52; 95% CI,.33 to.81; P =.004) and CNI alone or with other agents (sHR,.27; 95% CI,.14 to.53; P <.001) compared with CNI + mycophenolate. Although donor availability is modifiable only to a limited extent, choice of GVHD prophylaxis and selection of patients with good performance scores are key for improved outcomes.