Unrelated cord blood transplantation in patients with idiopathic refractory severe aplastic anemia: a nationwide phase 2 study

Blood. 2018 Aug 16;132(7):750-754. doi: 10.1182/blood-2018-01-829630. Epub 2018 May 14.


Outcomes remain poor for refractory severe aplastic anemia (SAA) patients. Alternative donor transplantation may be considered, but results from previous studies are not encouraging. We conducted a prospective nationwide phase 2 study to assess unrelated cord blood (CB) transplantation (CBT) efficacy and safety in refractory SAA patients (Aplastic Anemia and Cord Blood Transplantation protocol). To demonstrate a significant difference in 1-year survival from 20% (null hypothesis) to 50% (alternative hypothesis), we needed to include 25 transplanted patients and therefore included 26 (median age, 16 years). Eligibility criteria required 1 or 2 unrelated CB units, containing separately or together >4 × 107 frozen nucleated cells (NCs) per kilogram of recipient body weight. Conditioning regimen comprised fludarabine (FLU), cyclophosphamide (CY), antithymocyte globulin (ATG), and 2-Gy total body irradiation (TBI). With a median follow-up of 38.8 months, engraftment occurred in 23 patients (88%); cumulative incidences of grade II-IV acute and chronic graft-versus-host disease were 45.8% and 36%, respectively. Twenty-three patients were alive at 1 year, with an 88.5% overall survival (OS) rate, differing significantly from the expected 20% (P < .0001; 84% OS at 2 years). CBT with units containing ≥4 × 107 frozen NCs per kilogram is therefore a valuable curative option for young adults with refractory SAA and no available matched unrelated donors. This trial was registered at www.clinicaltrials.gov as #NCT01343953.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Alanine / administration & dosage
  • Alanine / analogs & derivatives
  • Allografts
  • Anemia, Aplastic / mortality*
  • Anemia, Aplastic / therapy*
  • Antilymphocyte Serum / administration & dosage
  • Child
  • Cord Blood Stem Cell Transplantation*
  • Disease-Free Survival
  • Female
  • Graft vs Host Disease / mortality
  • Graft vs Host Disease / prevention & control
  • Humans
  • Male
  • Survival Rate
  • Transplantation Conditioning*
  • Unrelated Donors*
  • Whole-Body Irradiation


  • Antilymphocyte Serum
  • fludalanine
  • Alanine

Supplementary concepts

  • Aplastic anemia, idiopathic

Associated data

  • ClinicalTrials.gov/NCT01343953