No Survival Benefit With Double- Versus Single-Unit Cord-Blood Transplantation

Double-unit cord-blood transplantation fails to boost survival in children and adolescents with haematological cancers

medwireNews: Double-unit cord-blood transplantation does not significantly extend survival compared with a single unit in children and adolescents with haematological cancers, research shows.

And it impairs platelet recovery and increases the risk of acute graft-versus-host disease (GVHD), report John Wagner, from the University of Minnesota in Minneapolis, USA, and colleagues.

The authors explain that the use of cord blood is limited by the finite number of haematopoietic progenitor cells that can be collected from a placenta, but that one of the strategies to overcome this limitation is the infusion of two units of cord blood.

Patients between the ages of 1 and 21 years diagnosed with high-risk acute leukaemia, chronic myeloid leukaemia or myelodysplastic syndrome were randomly assigned to receive either a double- (n=111) or single-unit cord-blood transplant (n=113) after a uniform myeloablative conditioning regimen and GVHD prophylaxis.

The researchers did not observe a significant difference in the 1-year overall survival rate between patients given two units compared with those who received just one unit, with rates of 65% and 73%, respectively.

The double- and single-unit groups also did not differ significantly with respect to 1-year disease-free survival rate (64 vs 70%) and incidence of neutrophil recovery (88 vs 89% at a median of 23 vs 21 days) in this multicentre, phase III trial.

However, the rate of platelet recovery was significantly lower in double-unit recipients than in those given a single unit, at 65% and 76%, respectively. Recovery was also less rapid in the double-unit group, occurring at a median of 84 days versus 58 days in the comparator group.

Double-unit recipients also fared significantly worse in terms of the occurrence of grade 3 and 4 acute GVHD, with 23% of participants developing grade 3 and 4 GVHD compared with 13% in the single-unit group.

Writing in The New England Journal of Medicine, the team comments that these findings contrast with those reported in previous studies, and speculate that “[p]erhaps the poorer platelet recovery after double-unit transplantation in this study was due to the higher rate of GVHD”.

But the researchers say: “Still, it must be recognized that most previous studies of double-unit transplantation involved adults, for whom the graft cell doses were lower.”

They speculate that they could have uncovered a threshold effect in their young patients, resulting in an increased rate of GVHD and lack of survival advantage.

Reference

Wagner JE, Jr, Eapen M, Carter S, et al. One-Unit versus Two-Unit Cord-Blood Transplantation for Hematologic Cancers. N Engl J Med 2014;371: 1685–1694. doi:10.1056/NEJMoa1405584

medwireNews (www.medwireNews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2014