title: Effectiveness of reducing infliximab dose interval in non-responder patients with refractory spondyloarthropathies. An open extension of a multicentre study.
abstract: OBJECTIVE
  To evaluate the therapeutic effectiveness of reducing the infliximab dose interval to 6 weeks in spondyloarthropathy patients not responding to 5 mg/kg every 8 weeks.
  
  
  METHODS
  After 30 weeks of infliximab therapy, 25 patients were classified as responders [Bath Ankylosing Spondylitis Activity Index (BASDAI) <4 cm or ESR <30 mm/h and CRP <5 mg/l, n = 15; group A] or non-responders (patients who did not achieve the response established for group A; n = 10; group B). Responders continued on 5 mg/kg every 8 weeks and non-responders decreased the dose interval to 6 weeks. BASDAI, Bath Ankylosing Spondylitis Functional Index (BASFI), ESR, CRP and ankylosing spondylitis assessment (ASAS) criteria were used to assess response.
  
  
  RESULTS
  At 62 weeks, 11 of 15 patients (73.3%, 95% confidence interval = 44.9-92.2%) from group A and three of 10 patients (30%, 95% confidence interval = 6.7-65.2) from group B were responders (P = 0.049). Eighty per cent (eight of 10 patients from group A) and 22.2% (two of 9 patients from group B) achieved 50% BASDAI improvement (P = 0.023), and nine of 11 patients (81.8%) and four of 10 (40%) from groups A and B, respectively, reached ASAS20 at 62 weeks (P = 0.08).
  
  
  CONCLUSIONS
  Patients on infliximab 5 mg/kg every 8 weeks with persistent disease activity may benefit from reducing the dose interval to 6 weeks.
authors.affiliation: Department of Rheumatology, Reina Sofia University Hospital of Córdoba, Córdoba. ecollantes@ctv.es
authors.forename: E
authors.initials: E
authors.lastname: Collantes-Estevez
authors.forename: M C
authors.initials: MC
authors.lastname: Muñoz-Villanueva
authors.forename: P
authors.initials: P
authors.lastname: Zarco
authors.forename: J C
authors.initials: JC
authors.lastname: Torre-Alonso
authors.forename: J
authors.initials: J
authors.lastname: Gratacós
authors.forename: C
authors.initials: C
authors.lastname: González
authors.forename: R
authors.initials: R
authors.lastname: Sanmartí
authors.forename: J D
authors.initials: JD
authors.lastname: Cañete
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000008:administration & dosage* / Q000627:therapeutic use; D018501:Antirheumatic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D000069285:Infliximab; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D025242:Spondylarthropathies / Q000188:drug therapy*; D017211:Treatment Failure; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: D000911:Antibodies, Monoclonal; D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein; D000069285:Infliximab