title: Abatacept reduces disease activity and ultrasound power Doppler in ACPA-negative undifferentiated arthritis: a proof-of-concept clinical and imaging study.
abstract: No proven treatment exists for ACPA-negative undifferentiated arthritis (UA). The aim of this study was to evaluate whether abatacept is effective in treating poor prognosis, ACPA-negative UA, including its effect on power Doppler on US (PDUS).
  
  
  
  A proof-of-concept, open-label, prospective study of 20 patients with DMARD-naïve, ACPA-negative UA (⩾2 joint synovitis) and PDUS ⩾ 1 with clinical and 20-joint US (grey scale/PDUS) assessments at baseline, 6, 12, 18 and 24 months. All patients received 12 months of abatacept (monotherapy for minimum first 6 months). The primary end point was a composite of the proportion of patients that at 6 months achieved DAS44 remission, a maximum of one swollen joint for at least 3 consecutive months and no radiographic progression (over 0-12 months).
  
  
  
  Twenty of the 23 patients screened were enrolled [14 female; mean (sd) age 53.4 (11.2) years, symptom duration 7.5 (0.9) months]. Two (10%) achieved the composite primary end point. A reduction in the mean (sd) DAS44 was observed from a baseline value of 2.66 (0.77) to 2.01 (0.81) at 6 months and to 1.78 (0.95) at 12 months. The DAS44 remission rates were 6/20 (30%; 95% CI: 15, 51%) at 6 months and 8/20 (40%; 95% CI: 22, 62%) at 12 months. A striking decrease in the median (interquartile range; IQR) total PDUS score was noted from 10 (4-23) at baseline to 3 (2-12) and 3 (0-5) at 6 and 12 months, respectively.
  
  
  
  This report is a first in potentially identifying an effective therapy, abatacept monotherapy, for poor-prognosis, ACPA-negative UA, supported by a clear reduction in PDUS. These data justify evaluation in a controlled study.
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds m.buch@leeds.ac.uk.|NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Maya H
authors.initials: MH
authors.lastname: Buch
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.|NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Elizabeth M A
authors.initials: EM
authors.lastname: Hensor
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.
authors.forename: Chadi
authors.initials: C
authors.lastname: Rakieh
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.
authors.forename: Jane E
authors.initials: JE
authors.lastname: Freeston
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.
authors.forename: Edward
authors.initials: E
authors.lastname: Middleton
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.
authors.forename: Sarah
authors.initials: S
authors.lastname: Horton
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.
authors.forename: Sudipto
authors.initials: S
authors.lastname: Das
authors.affiliation: Spire Sciences, Inc., Boca Raton, FL, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Peterfy
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.|NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Ai Lyn
authors.initials: AL
authors.lastname: Tan
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.|NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Wakefield
authors.affiliation: Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds.|NIHR Leeds Musculoskeletal Biomedical Research Unit, Leeds Teaching Hospitals NHS Trust, Leeds, UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Emery
mesh_terms: D000069594:Abatacept / Q000627:therapeutic use*; D000328:Adult; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001168:Arthritis / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000276:immunology; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging / Q000188:drug therapy / Q000276:immunology; D005260:Female; D050823:Hand Joints / Q000000981:diagnostic imaging; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D000071066:Patient Reported Outcome Measures; D010456:Peptides, Cyclic / Q000276:immunology; D011446:Prospective Studies; D011859:Radiography; D012074:Remission Induction; D012217:Rheumatoid Factor / Q000276:immunology; D012720:Severity of Illness Index; D013585:Synovitis / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000276:immunology; D018608:Ultrasonography, Doppler
chemical_list: D018501:Antirheumatic Agents; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D000069594:Abatacept; D012217:Rheumatoid Factor
keywords: ACPA; abatacept; inflammatory arthritis; ultrasound; undifferentiated arthritis