title: Therapeutic drug monitoring of infliximab in spondyloarthritis: an observational open-label study.
abstract: BACKGROUND
  Infliximab is a chimeric monoclonal antibody that binds to human tumor necrosis factor alpha and which is approved for refractory spondyloarthritis (SpA). Individual adjustment of infliximab dosage may help to improve the therapeutic response in SpA. We investigated whether a knowledge of infliximab serum concentration modifies physician decision and improves the control of disease activity in SpA.
  
  
  METHODS
  Thirty-two patients routinely treated with infliximab were included in an observational open-label study. On visit 1 (V1), according to disease activity, a preliminary therapeutic decision was selected among 4 therapeutic options (ie, decrease, increase, maintain the dosage of infliximab, or switch over for another treatment), and a blood sample was collected to measure infliximab trough serum concentration. The final therapeutic decision, based on both disease activity and infliximab serum concentration assessed at V1, was applied at the following infusion (V2). Clinical and biological evaluations were performed at V3 and V4 and compared with those at V1.
  
  
  RESULTS
  The measurement of infliximab trough concentration modified the therapeutic decision for 10 patients (31%). For both patients with increased or decreased infliximab dosage at V2, median Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) was similar at V3 or V4 as compared with that at V1. However, a trend for an inverse relationship between infliximab serum concentrations and BASDAI was observed.
  
  
  CONCLUSIONS
  Knowledge of infliximab trough concentration modified the therapeutic decision for SpA patients with predominantly axial symptoms but did not improve the control of disease activity as estimated by the BASDAI.
authors: Université François Rabelais de Tours, Centre National de la Recherche Scientifique UMR 6239 Génétique Immunothérapie Chimie et Cancer, Tours, France.
authors: Jean-Camille
authors: JC
authors: Méric
authors: Denis
authors: D
authors: Mulleman
authors: Emilie
authors: E
authors: Ducourau
authors: Francine
authors: F
authors: Lauféron
authors: Delphine Chu
authors: DC
authors: Miow Lin
authors: Hervé
authors: H
authors: Watier
authors: Philippe
authors: P
authors: Goupille
authors: Gilles
authors: G
authors: Paintaud
mesh_terms: D000328:Adult; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000097:blood; D000911:Antibodies, Monoclonal / Q000008:administration & dosage* / Q000097:blood*; D003657:Decision Making; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D000069285:Infliximab; D008297:Male; D008875:Middle Aged; D025241:Spondylarthritis / Q000097:blood* / Q000188:drug therapy*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000893:Anti-Inflammatory Agents; D000911:Antibodies, Monoclonal; D000069285:Infliximab