Stem cell transplantation for pediatric patients with adrenoleukodystrophy: A nationwide retrospective analysis in Japan.

BACKGROUND Adrenoleukodystrophy (ALD) is an X-linked recessive disorder and 30-40% of patients develop progressive cerebral neurodegeneration. For symptomatic ALD patients, allogeneic stem cell transplantation (SCT) is considered the standard treatment modality to stabilize or prevent the progression of neurological symptoms. METHODS We retrospectively analyzed the transplant outcomes of 99 pediatric patients with cerebral ALD in Japan. The conditioning regimens included Regimen A: fludarabine/melphalan/low-dose total body irradiation (TBI) with brain sparing (n = 39), Regimen B; busulfan/cyclophosphamide ± others (n = 23), Regimen C: melphalan/total lymphoid irradiation/thoracoabdominal irradiation ± anti-T lymphocyte globulin ± fludarabine (n = 27), and Regimen D: others (n = 10). RESULTS The 5-year overall survival (OS) and event-free survival (EFS) of all patients were 90.0% and 72.9%, respectively. The 5-year OS was 100.0% for Regimen A, 91.1% for Regimen B, 84.4% for Regimen C, and 67.5% for Regimen D (p = 0.028). The 5-year EFS was 78.3% for Regimen A, 78.0% for Regimen B, 70.4% for Regimen C, and 48.0% for Regimen D (p = 0.304). The OS marginally improved after 2007 compared with before 2006 (95.3% vs. 85.2%, p = 0.066), due to the improvement of cord blood transplantation (CBT) outcomes after 2007 compared with before 2006 (96.6% vs. 68.4%, p = 0.005). On magnetic resonance imaging of the brain, a reduced Loes score after SCT was only observed in one of the 15 bone marrow transplantation (BMT) patients, but in 5 of the 15 CBT patients (p = 0.173). CONCLUSIONS Our study revealed that a reduced conditioning regimen with fludarabine/melphalan/low-dose TBI provides better outcomes, and the results of CBT significantly improved after 2007.