title: One-unit versus two-unit cord-blood transplantation for hematologic cancers.
abstract: BACKGROUND
  Umbilical-cord blood has been used as the source of hematopoietic stem cells in an estimated 30,000 transplants. The limited number of hematopoietic cells in a single cord-blood unit prevents its use in recipients with larger body mass and results in delayed hematopoietic recovery and higher mortality. Therefore, we hypothesized that the greater numbers of hematopoietic cells in two units of cord blood would be associated with improved outcomes after transplantation.
  
  
  METHODS
  Between December 1, 2006, and February 24, 2012, a total of 224 patients 1 to 21 years of age with hematologic cancer were randomly assigned to undergo double-unit (111 patients) or single-unit (113 patients) cord-blood transplantation after a uniform myeloablative conditioning regimen and immunoprophylaxis for graft-versus-host disease (GVHD). The primary end point was 1-year overall survival.
  
  
  RESULTS
  Treatment groups were matched for age, sex, self-reported race (white vs. nonwhite), performance status, degree of donor-recipient HLA matching, and disease type and status at transplantation. The 1-year overall survival rate was 65% (95% confidence interval [CI], 56 to 74) and 73% (95% CI, 63 to 80) among recipients of double and single cord-blood units, respectively (P=0.17). Similar outcomes in the two groups were also observed with respect to the rates of disease-free survival, neutrophil recovery, transplantation-related death, relapse, infections, immunologic reconstitution, and grade II-IV acute GVHD. However, improved platelet recovery and lower incidences of grade III and IV acute and extensive chronic GVHD were observed among recipients of a single cord-blood unit.
  
  
  CONCLUSIONS
  We found that among children and adolescents with hematologic cancer, survival rates were similar after single-unit and double-unit cord-blood transplantation; however, a single-unit cord-blood transplant was associated with better platelet recovery and a lower risk of GVHD. (Funded by the National Heart, Lung, and Blood Institute and the National Cancer Institute; ClinicalTrials.gov number, NCT00412360.).
authors.affiliation: From the University of Minnesota Medical School, Minneapolis (J.E.W., M.R.V.); Medical College of Wisconsin, Milwaukee (M.E., D.M., M.M.H.); EMMES Corporation, Rockville, MD (S.C., Y.W.); BC Children's Hospital, Vancouver (K.R.S.), and University of Manitoba, Winnipeg (D.A.W.) - both in Canada; Children's Hospital of Philadelphia, Philadelphia (N.B.); Fred Hutchinson Cancer Research Center, Seattle (C.D.); Indiana University, Indianapolis (P.H.); University of Michigan, Ann Arbor (E.P.); University of California San Francisco Benioff Children's Hospital Oakland, Oakland (M.W.); and Duke University, Durham, NC (J.K.).
authors.forename: John E
authors.initials: JE
authors.lastname: Wagner
authors.forename: Mary
authors.initials: M
authors.lastname: Eapen
authors.forename: Shelly
authors.initials: S
authors.lastname: Carter
authors.forename: Yanli
authors.initials: Y
authors.lastname: Wang
authors.forename: Kirk R
authors.initials: KR
authors.lastname: Schultz
authors.forename: Donna A
authors.initials: DA
authors.lastname: Wall
authors.forename: Nancy
authors.initials: N
authors.lastname: Bunin
authors.forename: Colleen
authors.initials: C
authors.lastname: Delaney
authors.forename: Paul
authors.initials: P
authors.lastname: Haut
authors.forename: David
authors.initials: D
authors.lastname: Margolis
authors.forename: Edward
authors.initials: E
authors.lastname: Peres
authors.forename: Michael R
authors.initials: MR
authors.lastname: Verneris
authors.forename: Mark
authors.initials: M
authors.lastname: Walters
authors.forename: Mary M
authors.initials: MM
authors.lastname: Horowitz
authors.forename: Joanne
authors.initials: J
authors.lastname: Kurtzberg
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D036101:Cord Blood Stem Cell Transplantation / Q000009:adverse effects / Q000379:methods* / Q000401:mortality; D018572:Disease-Free Survival; D005260:Female; D006086:Graft vs Host Disease / Q000453:epidemiology / Q000517:prevention & control; D019337:Hematologic Neoplasms / Q000401:mortality / Q000628:therapy*; D006650:Histocompatibility Testing; D006801:Humans; D007167:Immunotherapy; D007223:Infant; D008297:Male; D015996:Survival Rate; D019172:Transplantation Conditioning; D055815:Young Adult