title: Idursulfase treatment of Hunter syndrome in children younger than 6 years: results from the Hunter Outcome Survey.
abstract: OBJECTIVE
  To use the Hunter Outcome Survey, an international database, to assess the safety and effectiveness of enzyme replacement therapy with idursulfase in patients with Hunter syndrome who started treatment before 6 years of age.
  
  
  METHODS
  The study population included all patients enrolled in the Hunter Outcome Survey who started idursulfase infusions (0.5 mg/kg every other week) before 6 years of age and who had at least one follow-up examination recorded.
  
  
  RESULTS
  The study population included 124 patients, younger than 6 years, who had a mean age at start of idursulfase of 3.6 ± 1.6 years (mean ± SD). The mean duration of treatment was 22.9 ± 14.6 months. A total of 69 infusion-related reactions occurred in 33 (26.6%) patients, including three serious infusion-related reactions occurring in a single patient. After at least 6 months of idursulfase, urine glycosaminoglycan levels decreased from 592 ± 188 to 218 ± 115 μg/mg creatinine (P < 0.0001, n = 34). Liver size, estimated by palpation, was also significantly decreased (P = 0.005, n = 23). Similar safety and effectiveness results were seen in patients who were aged 6 years or older when initiating idursulfase.
  
  
  CONCLUSIONS
  No new safety concerns were identified in patients younger than 6 years, and clinical benefit was suggested by the reduction in liver size.
authors.affiliation: Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. muenzer@med.unc.edu
authors.forename: Joseph
authors.initials: J
authors.lastname: Muenzer
authors.forename: Michael
authors.initials: M
authors.lastname: Beck
authors.forename: Roberto
authors.initials: R
authors.lastname: Giugliani
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Anna
authors.initials: A
authors.lastname: Tylki-Szymanska
authors.forename: Vassili
authors.initials: V
authors.lastname: Valayannopoulos
authors.forename: Ashok
authors.initials: A
authors.lastname: Vellodi
authors.forename: James E
authors.initials: JE
authors.lastname: Wraith
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D003625:Data Collection; D016208:Databases, Factual; D056947:Enzyme Replacement Therapy / Q000009:adverse effects / Q000379:methods*; D006025:Glycosaminoglycans / Q000652:urine; D006801:Humans; D007066:Iduronate Sulfatase / Q000008:administration & dosage* / Q000009:adverse effects; D007223:Infant; D007262:Infusions, Intravenous; D016532:Mucopolysaccharidosis II / Q000628:therapy* / Q000652:urine; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D006025:Glycosaminoglycans; D007066:Iduronate Sulfatase; C517982:idursulfase