Double-unit cord blood transplants don't boost survival
AT THE ANNUAL MEETING OF THE AMERICAN SOCIETY OF HEMATOLOGY
Major Finding: Overall survival at 1 year after umbilical cord blood transplant was 71% with a single-unit transplant and 65% with a double-unit transplant (P = .13).
Data Source: Prospective, randomized phase III trial in 224 children with hematologic malignancies.
Disclosures: The study was supported by the National Heart, Lung, and Blood Institute; the National Cancer Institute; and the Children’s Oncology Group. Dr. Wagner and his coauthors reported no relevant conflicts of interest.
ATLANTA – Survival was not enhanced among children with blood cancers after transplantation with two units of umbilical cord blood versus an adequately dosed single-unit transplant.
Among 224 children in a phase III study, overall survival at 1 year was 71% with a single-unit umbilical cord blood (UCB) transplant and 65% with a double-unit UCB transplant (P = .13).
Patrice Wendling/IMNG Medical News
All other outcomes were similar, except for a lower incidence of platelet recovery and higher incidence of grade III-IV acute graft-versus-host disease after double UCB transplants, Dr. John E. Wagner reported on behalf of the Blood and Marrow Transplant Clinical Trials Network at the annual meeting of the American Society of Hematology.
And for patients who don’t have an adequate single cord unit based on cell dose, "a double cord blood unit was certainly as good as, or an acceptable alternative, to the single," he said. "So it allowed us to extend the transplant experience."
One of the major shortcomings of UCB transplantation is that units containing a minimum of 2.5 x 107 total nucleated cells/kg of patient body weight are frequently unavailable. The optimal number of transplanted umbilical stem cells remains unclear, but cell dose is an important factor influencing engraftment, or the ability of cells to take root, and survival.
Pilot studies suggested that infusion of two partially HLA-matched UCB units is safe, leading investigators to hypothesize that higher cell doses achieved with double UCB transplant would translate into improved survival, explained Dr. Wagner, scientific director of clinical research for the adult and pediatric blood and bone marrow transplant program at the University of Minnesota Medical Center in Minneapolis.
Between December 2006 and February 2012, investigators at 32 transplant centers enrolled 224 patients, aged 1-21 years, with acute lymphoblastic leukemia (ALL), acute myeloid leukemia, natural killer cell leukemia, chronic myeloid leukemia, or myelodysplastic syndrome. All had at least two available UCB units – each at least 4 of 6 HLA-matched to the patient and 3 of 6 matched between units.