title: An observational cohort study of extended dosing (once every 2 weeks or once monthly) regimens with darbepoetin alfa in patients with chronic kidney disease not on dialysis: the EXTEND study.
abstract: BACKGROUND
  Darbepoetin alfa (DA) has been shown to be an effective treatment of anaemia in patients with chronic kidney disease (CKD) not on dialysis (NoD). EXTEND is an observational study assessing the effectiveness of DA administered once biweekly (Q2W) or monthly (QM) in a general CKD-NoD population.
  
  
  METHODS
  Adult CKD-NoD patients starting DA Q2W/QM treatment in June 2006 or later were eligible. Retrospective and/or prospective data including haemoglobin levels and erythropoiesis-stimulating agent (ESA) dosing were collected for 6 months before and 12 months after DA initiation. Mean Hb levels were calculated every 3 months, and ESA dose was converted to a geometric mean weekly DA equivalent dose and summarized monthly.
  
  
  RESULTS
  Data from 4278 patients showed that patients receiving ESA treatment before DA Q2W/QM initiation had a mean (95% confidence interval) Hb level of 11.9 g/dL (11.8-12.0 g/dL) at initiation and 11.6 g/dL (11.6-11.7 g/dL) at Months 10-12, with mean ESA dose of 22 μg/week (21-23 μg/week) prior to initiation, 16 μg/week (15-16 μg/week) at initiation and 16 μg/week (15-16 μg/week) at Month 12. In ESA-naive patients, Hb levels increased from 10.3 g/dL (10.2-10.3 g/dL) at initiation to 11.7 g/dL at Months 4-6 and were maintained at a mean level of 11.7 g/dL (11.7-11.8 g/dL) at Months 10-12, with mean ESA dose of 16 μg/week (16-17 μg/week) at initiation and 16 μg/week (16-17 μg/week) at Month 12. In the 85% of patients receiving DA at extended intervals (Q2W or less frequently) at Month 12, 12 patients (0.3%) experienced DA-related adverse reactions.
  
  
  CONCLUSIONS
  DA Q2W/QM was an effective treatment of anaemia in the general CKD-NoD patient population and a dose increase was not required in patients switching from a previous ESA regimen.
authors.affiliation: Klinik für Nephrologie und Dialyseverfahren, Klinikum Lüdenscheid, Lüdenscheid, Germany. j.galle@klinikum-luedenscheid.de
authors.forename: Jan-Christoph
authors.initials: JC
authors.lastname: Galle
authors.forename: Kathleen
authors.initials: K
authors.lastname: Claes
authors.forename: Istvan
authors.initials: I
authors.lastname: Kiss
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Winearls
authors.forename: Hans
authors.initials: H
authors.lastname: Herlitz
authors.forename: Alain
authors.initials: A
authors.lastname: Guerin
authors.forename: Salvatore
authors.initials: S
authors.lastname: Di Giulio
authors.forename: Michael G
authors.initials: MG
authors.lastname: Suranyi
authors.forename: Ian
authors.initials: I
authors.lastname: Bridges
authors.forename: Janet
authors.initials: J
authors.lastname: Addison
authors.forename: Mourad
authors.initials: M
authors.lastname: Farouk
mesh_terms: D000328:Adult; D000368:Aged; D000740:Anemia / Q000188:drug therapy* / Q000209:etiology*; D000068256:Darbepoetin alfa; D004921:Erythropoietin / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006397:Hematinics / Q000627:therapeutic use*; D006801:Humans; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000628:therapy; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D006435:Renal Dialysis; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D006397:Hematinics; D004921:Erythropoietin; D000068256:Darbepoetin alfa