title: The predictive value of serum S100A9 and response to etanercept is not confirmed in a large UK rheumatoid arthritis cohort.
abstract: The aim was to correlate protein concentrations of S100A9 in pretreatment serum samples with response to the tumour-necrosis factor (TNF) inhibitor drugs etanercept in a large UK replication cohort.
  
  
  
  Pretreatment serum samples from patients with RA (n = 236) about to commence treatment with etanercept had S100A9 serum concentration measured using an ELISA. Following the experimental procedure, S100A9 concentrations were analysed with respect to EULAR response.
  
  
  
  No evidence of association between S100A9 concentration and EULAR response to the TNF-inhibitor biologic drug etanercept was observed following multinomial logistic regression analysis (non-responder vs moderate responder, P = 0.957; and non-responder vs good responder, P = 0.316). Furthermore, no significant associations were observed when correlating pretreatment S100A9 concentrations with clinical parameters of disease activity (P > 0.05).
  
  
  
  In the largest replication cohort conducted to date, no evidence for association was observed to support the use of S100A9 as a clinical biomarker predictive of response to the TNF-inhibitor biologic drug etanercept.
authors.affiliation: Arthritis Research UK, Centre for Genetics and Genomics, Centre for Musculoskeletal Research, Division of Musculoskeletal and Dermatological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, The University of Manchester.
authors.forename: Samantha Louise
authors.initials: SL
authors.lastname: Smith
authors.affiliation: National Institute for Health Research Manchester Musculoskeletal Biomedical Research Unit, Central Manchester Foundation Trust and University of Manchester, Manchester Academic Health Science Centre.
authors.forename: Darren
authors.initials: D
authors.lastname: Plant
authors.affiliation: Arthritis Research UK, Centre for Genetics and Genomics, Centre for Musculoskeletal Research, Division of Musculoskeletal and Dermatological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, The University of Manchester.
authors.forename: Stephen
authors.initials: S
authors.lastname: Eyre
authors.affiliation: Arthritis Research UK, Centre for Epidemiology, Centre for Musculoskeletal Research, Division of Musculoskeletal and Dermatological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, The University of Manchester.
authors.forename: Kimme
authors.initials: K
authors.lastname: Hyrich
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds and National Institute of Health Research Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals National Health Service Trust, Leeds, UK.
authors.forename: Ann W
authors.initials: AW
authors.lastname: Morgan
authors.affiliation: University College Dublin School of Medicine and Medical Science, Conway Institute, University College Dublin, Dublin, Ireland.
authors.forename: Anthony G
authors.initials: AG
authors.lastname: Wilson
authors.affiliation: Musculoskeletal Research Group, Institute of Cellular Medicine, Newcastle University and National Institute of Health Research Newcastle Biomedical Research Centre, Newcastle upon Tyne National Health Service Foundation Trust, Newcastle upon Tyne, UK.
authors.forename: John D
authors.initials: JD
authors.lastname: Isaacs
authors.affiliation: Arthritis Research UK, Centre for Genetics and Genomics, Centre for Musculoskeletal Research, Division of Musculoskeletal and Dermatological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Sciences Centre, The University of Manchester.|National Institute for Health Research Manchester Musculoskeletal Biomedical Research Unit, Central Manchester Foundation Trust and University of Manchester, Manchester Academic Health Science Centre.
authors.forename: Anne
authors.initials: A
authors.lastname: Barton
mesh_terms: D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000188:drug therapy*; D015415:Biomarkers / Q000378:metabolism; D040502:Calgranulin B / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D000068800:Etanercept / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D015415:Biomarkers; D040502:Calgranulin B; D000068800:Etanercept
keywords: biomarker; etanercept; precision medicine; protein; rheumatoid arthritis; treatment response