Hematopoietic stem cell transplantation in inborn errors of metabolism-a retrospective analysis on behalf of the pediatric disease working party from the Brazilian Society of Bone Marrow Transplantation and Cellular Therapy

Bone Marrow Transplant. 2025 Jan 26. doi: 10.1038/s41409-025-02512-6. Online ahead of print.

Abstract

Hematopoietic stem cell transplantation (HSCT) is an established treatment for selected patients with inborn errors of metabolism. In this first report from the PDWP-SBTMO, we included 105 patients transplanted between 1988 and 2021 across six Brazilian HSCT centers. The most prevalent diseases were X-linked adrenoleukodystrophy (n = 61) and mucopolysaccharidosis (type I n = 20; type II n = 10), with a median age at HSCT of 8.7 years and 2.1 years, respectively. Most conditioning regimens were myeloablative and busulfan-based. With a median follow-up of 6.7 years, the 5-years overall survival (OS) was 75% (95% CI, 0.65-0.82) with a superior 5-years OS for those transplanted after 2010 (87% vs. 63%, p = 0.01). Higher risk of death was associated with the use of haploidentical donor (HR8.86, p 0.021), unrelated cord blood (HR 8.76, p 0.005), unrelated donor (HR 5.91, p 0.02), and for HSCT performed before 2010 (HR 4.16, p = 0.0015). The CI of acute GVHD was 24.8%, while chronic GVHD was 9.5%. Major causes of death were infections (n = 8), GVHD (n = 6), and neurologic progression (n = 3). Despite improvements in transplant outcomes since 2011, challenges persist, emphasizing the need for early diagnosis, timely transplantation and expanding HSCT centers with expertise in the field.