title: Impact of baseline anti-cyclic citrullinated peptide-2 antibody concentration on efficacy outcomes following treatment with subcutaneous abatacept or adalimumab: 2-year results from the AMPLE trial.
abstract: OBJECTIVE
  To examine whether baseline anti-cyclic citrullinated peptide-2 (CCP2) antibody status and concentration correlated with clinical outcomes in patients treated with abatacept or adalimumab on background methotrexate (MTX) in the 2-year AMPLE (Abatacept versus adaliMumab comParison in bioLogic-naïvE rheumatoid arthritis subjects with background MTX) study.
  
  
  METHODS
  In this exploratory analysis, anti-CCP2 antibody concentration was measured at baseline, and antibody-positive patients were divided into equal quartiles, Q1-Q4, representing increasing antibody concentrations. Clinical outcomes analysed by baseline anti-CCP2 status and quartile included change from baseline in disease activity and disability and remission rates.
  
  
  RESULTS
  Baseline characteristics were generally comparable across quartiles and treatment groups. In both treatment groups, anti-CCP2 antibody-negative patients responded less well than antibody-positive patients. At year 2, improvements in disease activity and disability and remission rates were similar across Q1-Q3, but were numerically higher in Q4 in the abatacept group; in contrast, treatment effects were similar across all quartiles in the adalimumab group.
  
  
  CONCLUSIONS
  In AMPLE, baseline anti-CCP2 positivity was associated with a better response for abatacept and adalimumab. Patients with the highest baseline anti-CCP2 antibody concentrations had better clinical response with abatacept than patients with lower concentrations, an association that was not observed with adalimumab.
  
  
  BACKGROUND
  NCT00929864.
authors.affiliation: VA Palo Alto Health Care System and Division of Immunology and Rheumatology, Stanford University School of Medicine, Palo Alto, California, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Sokolove
authors.affiliation: Department of Rheumatology, University of Colorado, Denver, Colorado, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Schiff
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA.
authors.forename: Roy
authors.initials: R
authors.lastname: Fleischmann
authors.affiliation: Department of Rheumatology & Immunology, Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Weinblatt
authors.affiliation: Immunoscience, Bristol-Myers Squibb, Princeton, New Jersey, USA.
authors.forename: Sean E
authors.initials: SE
authors.lastname: Connolly
authors.affiliation: Immunoscience, Bristol-Myers Squibb, Princeton, New Jersey, USA.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Johnsen
authors.affiliation: Global Biometric Sciences, Bristol-Myers Squibb, Princeton, New Jersey, USA.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Immunoscience, Bristol-Myers Squibb, Princeton, New Jersey, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Maldonado
authors.affiliation: Immunoscience, Bristol-Myers Squibb, Princeton, New Jersey, USA.
authors.forename: Salil
authors.initials: S
authors.lastname: Patel
authors.affiliation: VA Palo Alto Health Care System and Division of Immunology and Rheumatology, Stanford University School of Medicine, Palo Alto, California, USA.
authors.forename: William H
authors.initials: WH
authors.lastname: Robinson
mesh_terms: D000069594:Abatacept / Q000627:therapeutic use*; D000068879:Adalimumab / Q000627:therapeutic use*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology*; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007279:Injections, Subcutaneous; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000276:immunology*; D011379:Prognosis; D016037:Single-Blind Method; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018501:Antirheumatic Agents; D001323:Autoantibodies; D007074:Immunoglobulin G; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide; D000069594:Abatacept; D000068879:Adalimumab; D008727:Methotrexate
keywords: Ant-CCP; Autoantibodies; DMARDs (biologic); Rheumatoid Arthritis