title: The effect of etanercept on osteoclast precursor frequency and enhancing bone marrow oedema in patients with psoriatic arthritis.
abstract: OBJECTIVE
  The frequency of osteoclast precursors (OCPF) and the presence of bone marrow oedema (BMO) are potential response biomarkers in psoriatic arthritis (PsA). Previous studies suggest a central role for tumour necrosis factor (TNF) in the formation of osteoclast precursors. To better understand this association, the effect of etanercept on OCPF and BMO was analysed in PsA patients with erosive arthritis.
  
  
  METHODS
  A total of 20 PsA patients with active erosive PsA were enrolled. Etanercept was administered twice weekly for 24 weeks. OCPF was measured and clinical assessments were performed at baseline, 2, 12 and 24 weeks. Gadolinium enhanced MR images were obtained at baseline and 24 weeks.
  
  
  RESULTS
  Significant improvements in joint score (p<0.001), HAQ scores (p<0.001) and SF-36 parameters were observed after 6 months of therapy with etanercept compared to baseline. The median OCPF decreased from 24.5 to 9 (p = 0.04) and to 7 (p = 0.006) after 3 months and 6 months of treatment, respectively. MR images were available for 13 patients. The BMO volume decreased in 47 and increased in 31 sites at 6 months. No correlation was noted between OCPF, BMO and clinical parameters.
  
  
  CONCLUSIONS
  The rapid decline in OCPF and overall improvement in BMO after anti-TNFalpha therapy provides one mechanism to explain the anti-erosive effects of TNF blockade in PsA. Persistence of BMO after etanercept treatment, despite a marked clinical response, was unexpected, and suggests ongoing subchondral inflammation or altered remodelling in PsA bone.
authors.affiliation: Department of Allergy, Immunology and Rheumatology, University of Rochester, New York, USA. allen_anandarajah@urmc.rochester.edu
authors.forename: A P
authors.initials: AP
authors.lastname: Anandarajah
authors.forename: E M
authors.initials: EM
authors.lastname: Schwarz
authors.forename: S
authors.initials: S
authors.lastname: Totterman
authors.forename: J
authors.initials: J
authors.lastname: Monu
authors.forename: C Y
authors.initials: CY
authors.lastname: Feng
authors.forename: T
authors.initials: T
authors.lastname: Shao
authors.forename: S A
authors.initials: SA
authors.lastname: Haas-Smith
authors.forename: C T
authors.initials: CT
authors.lastname: Ritchlin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D015535:Arthritis, Psoriatic / Q000150:complications / Q000188:drug therapy / Q000473:pathology*; D001855:Bone Marrow Diseases / Q000188:drug therapy / Q000209:etiology; D002452:Cell Count; D004487:Edema / Q000188:drug therapy / Q000209:etiology; D000068800:Etanercept; D005260:Female; D005384:Finger Joint / Q000473:pathology; D006801:Humans; D007074:Immunoglobulin G / Q000494:pharmacology* / Q000627:therapeutic use; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D010010:Osteoclasts / Q000187:drug effects* / Q000473:pathology; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use; D012720:Severity of Illness Index; D013234:Stem Cells / Q000187:drug effects*; D016896:Treatment Outcome; D014955:Wrist Joint / Q000473:pathology
chemical_list: D018501:Antirheumatic Agents; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D000068800:Etanercept