Fludarabine-based reduced toxicity yet myeloablative conditioning is effective and safe particularly in patients with high-risk thalassemia undergoing allogeneic transplantation

Pediatr Blood Cancer. 2018 Nov;65(11):e27312. doi: 10.1002/pbc.27312. Epub 2018 Aug 1.

Abstract

Introduction: Thalassemia major (TM) is an inherited disorder caused by ineffective erythropoiesis. At the present time, allogeneic stem cell transplantation (allo-SCT) is a curative option. Conventional busulfan and cyclophosphamide based myeloablative conditioning regimens are limited by increased toxicity, especially in high-risk patients. Replacement of cyclophosphamide with fludarabine has reduced toxicity and nonrelapse mortality (NRM), thus improving outcomes. We analyzed long-term data of our fludarabine-based myeloablative, reduced toxicity protocol, specifically in high-risk patients.

Methods: We retrospectively analyzed a cohort of 47 consecutive patients with TM undergoing allo-SCT from matched donors, using the fludarabine-based regimen (reduced toxicity regimen). The median age of the cohort was 10 years. Thirty-eight patients (80%) were in the high-risk and nine patients (20%) were in the low-risk category. The primary aim of this analysis was thalassemia-free survival (TFS).

Results: The rejection rate was 11% within high-risk patients with NRM of 2%. With a median follow-up period of 7 years (1-15 years), the 10-year TFS in the entire cohort was 87%, and the overall survival (OS) was 97%. The 10-year TFS and OS among the low-risk and high-risk groups were 90% versus 84%, respectively (P = 0.45) and 100% versus 96%, respectively (P = 0.5), and both subsets of patients did equally well.

Conclusion: In conclusion, replacement of high-dose cyclophosphamide with fludarabine is well tolerated with minimal regimen-related toxicity and acceptable rejection rates, especially in high-risk patients.

Keywords: fludarabine conditioning; thalassemia; transplantation.

MeSH terms

  • Adolescent
  • Busulfan / therapeutic use
  • Child
  • Child, Preschool
  • Female
  • Hematopoietic Stem Cell Transplantation / methods*
  • Humans
  • Male
  • Myeloablative Agonists / therapeutic use*
  • Retrospective Studies
  • Thalassemia / surgery*
  • Transplantation Conditioning / methods*
  • Transplantation, Homologous / methods
  • Vidarabine / analogs & derivatives*
  • Vidarabine / therapeutic use

Substances

  • Myeloablative Agonists
  • Vidarabine
  • Busulfan
  • fludarabine