title: Outcomes of Long-Term Treatment with Laronidase in Patients with Mucopolysaccharidosis Type I.
abstract: OBJECTIVE
  To evaluate long-term outcomes of laronidase enzyme replacement therapy in patients with attenuated mucopolysaccharidosis type I.
  
  
  METHODS
  Retrospective analyses of case notes, laboratory results, and data from clinical trials were used to evaluate urinary glycosaminoglycans, forced vital capacity (FVC), 6-minute walk test (6MWT), height-for-age Z score, cardiac valve function, corneal clouding, and visual acuity in 35 patients with attenuated mucopolysaccharidosis type I (Hurler-Scheie and Scheie syndromes) for up to 10 years following the initiation of laronidase therapy.
  
  
  RESULTS
  Statistically significant (P < .001) reductions in mean urinary glycosaminoglycan levels relative to baseline were observed 6 months after treatment initiation and were sustained throughout follow-up. Disease remained stable after treatment initiation with no statistically significant changes in mean FVC, 6MWT, or height-for-age Z score. At last assessments, mitral and aortic valve function remained stable in 65% (22/34) of patients; corneal clouding remained stable in 78% (18/23); visual acuity remained stable in 33% (8/24) and improved in 42% (10/24) of patients. Younger patients (<10 years at treatment initiation) maintained disease measures closer to norms for age for FVC, 6MWT, and height and showed fewer deteriorations in mitral and aortic valve disease and corneal clouding compared with patients aged ≥10 years at treatment initiation.
  
  
  CONCLUSIONS
  Laronidase treatment resulted in disease stabilization in the majority of patients with a mean follow-up of 6.1 years. Data suggest that early treatment may result in better outcomes.
authors: Willink Biochemical Genetic Unit, Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester, UK. Electronic address: sarah.laraway@elht.nhs.uk.
authors: Sarah
authors: S
authors: Laraway
authors: Willink Biochemical Genetic Unit, Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester, UK.
authors: Jean
authors: J
authors: Mercer
authors: Willink Biochemical Genetic Unit, Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester, UK.
authors: Elisabeth
authors: E
authors: Jameson
authors: Manchester Royal Eye Hospital, Central Manchester University Hospitals National Health Service Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK; Centre for Ophthalmology and Vision Sciences, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK.
authors: Jane
authors: J
authors: Ashworth
authors: Willink Biochemical Genetic Unit, Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester, UK.
authors: Pauline
authors: P
authors: Hensman
authors: Willink Biochemical Genetic Unit, Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester, UK.
authors: Simon A
authors: SA
authors: Jones
mesh_terms: D002648:Child; D002675:Child, Preschool; D056947:Enzyme Replacement Therapy / Q000379:methods*; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006025:Glycosaminoglycans / Q000652:urine; D006801:Humans; D007068:Iduronidase / Q000627:therapeutic use*; D008297:Male; D008059:Mucopolysaccharidosis I / Q000188:drug therapy*; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity; D014797:Vital Capacity
chemical_list: D006025:Glycosaminoglycans; D007068:Iduronidase
keywords: MPS I; enzyme replacement therapy; laronidase; mucopolysaccharidosis type I