Survival analysis of haematopoietic cell transplantation for childhood cerebral X-linked adrenoleukodystrophy: a comparison study

Background: Favourable outcomes have been reported for patients with childhood cerebral adrenoleukodystrophy (CCALD) who had received haematopoietic cell transplantation (HCT) at the early stage of cerebral involvement. However, comparative data for non-transplanted CCALD patients are limited. We analysed survival of CCALD patients who had not received HCT and, in a subgroup with early cerebral disease, compared survival in those who underwent HCT with those who did not. Methods: Retrospective survival analyses were done on 283 CCALD patients identified at the Kennedy Krieger Institute who had not received HCT, focusing on a 30-member early stage cerebral subgroup whose neurological disability and MRI severity scores matched those in a 19-member transplanted subgroup previously reported. A Kaplan-Meier survival curve and log-rank test were used for survival analysis and to estimate the difference between the survival probabilities of the groups with statistical significance set at α=0·05. Findings: Mean age at onset of symptoms in the entire 283 non-transplanted group was 7 years (SD 2 years). 131 (46%) patients died during the mean follow-up period of 5·9 years (5·3) at a mean age of 12·3 years (4·9). 5-year survival was 66%. The 5-year survival probability of 54% in the early stage group was significantly poorer (χ²=7·47, p=0·006) than the 5-year survival of 95% in the transplanted group with early stage cerebral disease. Interpretation: HCT done in the early and progressive stages of CCALD is beneficial, and our data support the recommendation that transplantation be offered to patients in the early stages of CCALD.