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Similar Survival Rates in Children with High Risk Blood Cancers Transplanted with One Versus Two Umbilical Cord Blood Units

Results of a multi-center trial published in New England Journal of Medicine

October 29 2014

Children with blood cancer have previously been shown to benefit from umbilical cord blood transplants despite HLA mismatch, making it an important alternative for patients who cannot find a matched unrelated donor. However, the limited number of cells in a single cord blood unit obtained from a placenta after the birth of a child has curbed its potential benefits. Based on promising early studies, a new study was performed to compare transplant outcomes in children transplanted with one or two partially matched cord blood units. According to the study published in the New England Journal of Medicine, survival rates were high in both treatment arms with no differences in survival whether transplanted with one or two units. However, the study revealed several significant advantages in children transplanted with a single cord blood unit—most notably, a lower risk of graft-versus-host disease (GVHD).

The multi-center clinical trial—conducted by the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) in collaboration with the Pediatric Blood and Marrow Transplant Consortium and the Children’s Oncology Group—followed the progress of 224 children with high-risk leukemia and myelodysplastic syndrome who were randomized to receive either a single- or double-unit cord blood transplant between December 2006 and February 2012. Umbilical cord blood, a rich source of blood-forming stem cells, has previously been shown to benefit many patients with leukemia and myelodysplasia and other diseases, including bone marrow failure syndromes, hemoglobinopathies, inherited immune deficiencies and certain metabolic diseases.

“Based on promising early studies using two cord blood units in adults for whom one unit is often not sufficient, we designed this study in order to determine if the higher number of blood-forming stem cells in two cord blood units might improve survival,” explained John E. Wagner, Jr., M.D., lead author of the study and director of the Blood and Marrow Transplantation Program in the Department of Pediatrics at the University of Minnesota. “What we found, however, was that both treatment arms performed very well with similar rates of white blood cell recovery and survival.”

Still, the trial showed some differences. Children transplanted with a single cord unit had faster recovery rates for platelets, the cell components important in clotting, and lower risks of GVHD, a condition where the transplanted donor blood immune cells recognize the patient’s body as foreign causing a number of complications.

“This is helpful news for physicians considering the best treatment options for their patients,” said Joanne Kurtzberg, M.D., chief scientific officer of the Robertson Clinical and Translational Cell Therapy Program, director of the Pediatric Blood and Marrow Transplant Program, co-director of the Stem Cell Laboratory and director of the Carolinas Cord Blood Bank at Duke University Medical Center. “We found that children who have a cord blood unit with an adequate number of cells do not benefit from receiving two units. This reduces the cost of a cord blood transplant for the majority of pediatric patients needing the procedure. However, for larger children without an adequately dosed single cord blood unit, using two units will provide access to a potentially life-saving transplant.”

“The involvement of multiple research partners was instrumental to the success of the study completion,” added Dennis Confer, M.D., chief medical officer for the National Marrow Donor Program® (NMDP)/Be The Match® and associate scientific director for CIBMTR. “This trial is a testament to the importance of the BMT CTN and the collaboration of partners like the Children’s Oncology Group,” Confer explained.

Mary Horowitz, M.D., M.S., chief scientific director of CIBMTR and professor of medicine at the Medical College of Wisconsin, concurred. “Because of this tremendous collaboration, we were able to expand the scale of this research to multiple transplant centers across the United States and Canada. And the results will undoubtedly improve clinical practice, and most importantly, patient outcomes.”

Visit to access the full study.

About the BMT CTN
The Blood and Marrow Transplant Clinical Trials Network (BMT CTN) conducts well-designed, multi-institutional trials of high scientific merit, focused directly on improving survival for patients undergoing hematopoietic cell transplantation (HCT). The BMT CTN has opened more than 33 multi-institutional phase II and III trials, completed accrual to 24 trials, involved more than 100 transplant centers, and enrolled nearly 6,200 patients to participate on trials.

The BMT CTN has answered relevant research questions in both common and rare diseases. Its research studies include leukemia, myelodysplasia, lymphoma and multiple myeloma as well as rare transplant indications, such as aplastic anemia, sickle cell disease, human immunodeficiency virus (HIV)-associated cancers and hemophagocytic syndromes/primary immune deficiencies.

BMT CTN is funded by the National Heart, Lung, and Blood Institute and National Cancer Institute at the National Institutes of Health (NIH) and is a collaborative effort of 20 Core Transplant Centers/Consortia, CIBMTR, the National Marrow Donor Program (NMDP)/Be The Match and the EMMES Corporation. CIBMTR is a research collaboration between the NMDP/Be The Match and the Medical College of Wisconsin.

More information about the BMT CTN can be found at

About The Children’s Oncology Group
The Children’s Oncology Group ( is the world’s largest organization devoted exclusively to childhood and adolescent cancer research. The Children’s Oncology Group (COG) unites over 8,000 experts in childhood cancer at more than 200 leading children’s hospitals, universities, and cancer centers across North America, Australia, New Zealand, and parts of Europe in the fight against childhood cancer. Today, more than 90% of the13,500 children and adolescents diagnosed with cancer each year in the United States are cared for at COG member institutions. Research performed by the Children’s Oncology Group institutions over the past fifty years has transformed childhood cancer from a virtually incurable disease to one with a combined 5-year survival rate of 80%. COG’s mission is to improve the cure rate and outcome for all children with cancer.

Caroline Marin, University of Minnesota
612-624-5680 / 651-497-5530

Kirsten Lesak-Greenberg, for BMT CTN and NMDP/Be The Match
612-817-6442 / 763-300-9254

Maureen Mack, Medical College of Wisconsin
414-955-4744 / 414-750-5266

Carla Casey, EMMES Corporation