title: Quality of life is improved and kidney function preserved in patients with nephropathic cystinosis treated for 2 years with delayed-release cysteamine bitartrate.
abstract: OBJECTIVE
  To determine the long-term effects of delayed-release cysteamine bitartrate (DR-CYS) based on our previous work that established the short-term noninferiority of DR-CYS every 12 hours compared with immediate-release cysteamine bitartrate every 6 hours.
  
  
  METHODS
  We conducted a prospective, controlled, open label, single-arm study of DR-CYS for 2 years in 40 patients to assess efficacy in depletion of cystine in peripheral white blood cells, to assess the dose required to maintain white blood cell content of cystine <1 nmol ½ cystine/mg protein, to measure quality of life using the Pediatric Quality of Life Inventory, change in estimated glomerular filtration rate, and change in height Z-score.
  
  
  RESULTS
  Through 24 months of study, the mean white blood cell content of cystine was always <1 nmol ½ cystine/mg protein, and the dose of DR-CYS decreased from 43.5-40.1 mg/kg/d (P = .05), and the significant improvement in social function, school function, and in total function scores on the Pediatric Quality of Life Inventory remained. The estimated glomerular filtration rate was maintained and growth velocity was maintained at 24 months compared with the baseline height Z-score.
  
  
  CONCLUSIONS
  The use of a DR-CYS administered every 12 hours to patients with cystinosis is of great benefit to their quality of life and to important biomarkers of disease control, when studied in a prospective, controlled fashion. We suggest that DR-CYS should be considered for substrate depletion in patients with cystinosis.
authors.affiliation: Division of Kidney Diseases, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, and The Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL. Electronic address: c-langman@northwestern.edu.
authors.forename: Craig B
authors.initials: CB
authors.lastname: Langman
authors.affiliation: Division of Pediatric Nephrology, Emory University, and Children's Healthcare of Atlanta, Atlanta, GA.
authors.forename: Larry A
authors.initials: LA
authors.lastname: Greenbaum
authors.affiliation: Stanford University Medical Center, Stanford, CA.
authors.forename: Paul
authors.initials: P
authors.lastname: Grimm
authors.affiliation: Stanford University Medical Center, Stanford, CA.
authors.forename: Minnie
authors.initials: M
authors.lastname: Sarwal
authors.affiliation: Reference Center for Renal Diseases, Hôpital Necker Enfants Malades, Paris, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Niaudet
authors.affiliation: Hôpital Robert Debré, Paris, France.
authors.forename: Georges
authors.initials: G
authors.lastname: Deschenes
authors.affiliation: Radboud University, Nijmegen, The Netherlands.
authors.forename: Elisabeth A M
authors.initials: EA
authors.lastname: Cornelissen
authors.affiliation: Pediatric Nephrology and Endocrinology, CHU Montpellier, Montpellier, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Morin
authors.affiliation: Pediatric Service and INSERM U820, CHU Lyon, Bron, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Cochat
authors.affiliation: Baylor College of Medicine and Texas Children's Hospital, Houston, TX.
authors.forename: Ewa
authors.initials: E
authors.lastname: Elenberg
authors.affiliation: Division of Kidney Diseases, Department of Pediatrics, Feinberg School of Medicine, Northwestern University, and The Ann and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL.
authors.forename: Christian
authors.initials: C
authors.lastname: Hanna
authors.affiliation: Clinical Investigation Center, INSERM, Bron, France.
authors.forename: Segolene
authors.initials: S
authors.lastname: Gaillard
authors.affiliation: Raptor Pharmaceutical Inc, Novato, CA.
authors.forename: Mary Jo
authors.initials: MJ
authors.lastname: Bagger
authors.affiliation: Raptor Pharmaceutical Inc, Novato, CA.
authors.forename: Patrice
authors.initials: P
authors.lastname: Rioux
mesh_terms: D002648:Child; D003543:Cysteamine / Q000008:administration & dosage*; D065104:Cystine Depleting Agents / Q000008:administration & dosage*; D003554:Cystinosis / Q000188:drug therapy* / Q000503:physiopathology*; D003692:Delayed-Action Preparations; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011788:Quality of Life; D013997:Time Factors
chemical_list: D065104:Cystine Depleting Agents; D003692:Delayed-Action Preparations; D003543:Cysteamine