title: Serum MMP-3 level as a biomarker for monitoring and predicting response to etanercept treatment in ankylosing spondylitis.
abstract: OBJECTIVE
  To investigate whether level of serum matrix metalloproteinase-3 (MMP-3) can serve as a biomarker for monitoring and predicting response to etanercept treatment in patients with ankylosing spondylitis (AS) in daily clinical practice.
  
  
  METHODS
  Ninety-two consecutive AS outpatients with active disease who started etanercept treatment were included in this longitudinal observational study. Clinical data were collected prospectively at baseline and after 3 and 12 months of treatment. At the same timepoints, serum MMP-3 levels were measured retrospectively by ELISA.
  
  
  RESULTS
  Since baseline serum MMP-3 levels were significantly higher in male compared to female patients with AS, data analysis was split for gender. Changes in serum MMP-3 levels after etanercept treatment correlated positively with changes in clinical assessments of disease activity and physical function in both male and female patients. Receiver operating characteristic analysis in male patients showed that baseline serum MMP-3 levels had poor accuracy (AUC < 0.7) to discriminate between Assessments in Ankylosing Spondylitis 20 (ASAS20) or ASAS40 responders and nonresponders after 3 or 12 months of treatment. The accuracy of change in serum MMP-3 levels from baseline to 3 months in predicting response after 3 or 12 months of treatment was poor for ASAS40 (AUC < 0.7) or moderate for ASAS20 (AUC = 0.752 and 0.744, respectively), and was not superior to the accuracy of change in the currently used objective biomarkers, erythrocyte sedimentation rate and C-reactive protein.
  
  
  CONCLUSIONS
  Although significant changes in serum MMP-3 levels were found after etanercept treatment, data analysis indicates that serum MMP-3 levels are not very useful for monitoring and predicting response to etanercept treatment in patients with AS in daily clinical practice.
authors.affiliation: Department of Rheumatology and Clinical Immunology, University Medical Center Groningen, University of Groningen, The Netherlands. S.Arends@reuma.umcg.nl
authors.forename: Suzanne
authors.initials: S
authors.lastname: Arends
authors.forename: Eveline
authors.initials: E
authors.lastname: van der Veer
authors.forename: Henk
authors.initials: H
authors.lastname: Groen
authors.forename: Pieternella M
authors.initials: PM
authors.lastname: Houtman
authors.forename: Tim L T A
authors.initials: TL
authors.lastname: Jansen
authors.forename: Martha K
authors.initials: MK
authors.lastname: Leijsma
authors.forename: Johan
authors.initials: J
authors.lastname: Bijzet
authors.forename: Pieter C
authors.initials: PC
authors.lastname: Limburg
authors.forename: Cees G M
authors.initials: CG
authors.lastname: Kallenberg
authors.forename: Anneke
authors.initials: A
authors.lastname: Spoorenberg
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Brouwer
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood*; D000068800:Etanercept; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000627:therapeutic use*; D008137:Longitudinal Studies; D008297:Male; D019278:Matrix Metalloproteinase 3 / Q000097:blood*; D008875:Middle Aged; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use*; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000097:blood* / Q000188:drug therapy* / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D019278:Matrix Metalloproteinase 3; D000068800:Etanercept