title: Development of antidrug antibodies against adalimumab and association with disease activity and treatment failure during long-term follow-up.
abstract: BACKGROUND
  Short-term data on the immunogenicity of monoclonal antibodies showed associations between the development of antidrug antibodies and diminished serum drug levels, and a diminished treatment response. Little is known about the clinical relevance of antidrug antibodies against these drugs during long-term follow-up.
  
  
  OBJECTIVE
  To examine the course of antidrug antibody formation against fully human monoclonal antibody adalimumab and its clinical relevance during long-term (3-year) follow-up of patients with rheumatoid arthritis (RA).
  
  
  METHODS
  Prospective cohort study February 2004-September 2008; end of follow-up was September 2010. All 272 patients were diagnosed with RA and started treatment with adalimumab in an outpatient clinic.
  
  
  METHODS
  Disease activity was monitored and trough serum samples were obtained at baseline and 8 time points to 156 weeks. Serum adalimumab concentrations and antiadalimumab antibody titers were determined after follow-up. Treatment discontinuation, minimal disease activity, and clinical remission were compared for patients with and without antiadalimumab antibodies.
  
  
  RESULTS
  After 3 years, 76 of 272 patients (28%) developed antiadalimumab antibodies--51 of these (67%) during the first 28 weeks of treatment. Patients without antiadalimumab antibodies had much higher adalimumab concentrations (median, 12 mg/L; IQR, 9-16 mg/L) compared with patients with antibody titers from 13 to 100 AU/mL (median, 5 mg/L; IQR, 3-9 mg/L; regression coefficient, -4.5; 95% CI, -6.0 to -2.9; P < .001) and also those greater than 100 AU/mL (median, 0 mg/L; IQR, 0-3 mg/L; regression coefficient, -7.1; 95% CI, -8.4 to -5.8; P < .001). Patients with antiadalimumab antibodies more often discontinued participation due to treatment failure (n = 29 [38%]; hazard ratio [HR], 3.0; 95% CI, 1.6-5.5; P < .001) compared with antiadalimumab antibody-negative ones (n = 28 [14%]). Ninety-five of 196 patients (48%) without antiadalimumab antibodies had minimal disease activity vs 10 of 76 patients (13%) with antiadalimumab antibodies; patients with antiadalimumab antibodies less often had sustained minimal disease activity score in 28 joints (DAS28) (< 3.2; HR, 3.6; 95% CI, 1.8-7.2; P < .001) compared with antiadalimumab antibody-negative ones. Three of 76 patients (4%) with antiadalimumab antibodies achieved sustained remission compared with 67 of 196 (34%) antiadalimumab antibody-negative ones; patients with antiadalimumab antibodies less often achieved remission (DAS28 < 2.6; HR, 7.1; 95% CI, 2.1-23.4; P < .001) compared with antiadalimumab antibody-negative ones.
  
  
  CONCLUSIONS
  Among outpatients with RA in whom adalimumab was started over 3 years, the development of antidrug antibodies was associated with lower adalimumab concentration and lower likelihood of minimal disease activity or clinical remission.
authors.affiliation: Jan van Breemen Research Institute, Amsterdam, The Netherlands.
authors.forename: Geertje M
authors.initials: GM
authors.lastname: Bartelds
authors.forename: Charlotte L M
authors.initials: CL
authors.lastname: Krieckaert
authors.forename: Michael T
authors.initials: MT
authors.lastname: Nurmohamed
authors.forename: Pauline A
authors.initials: PA
authors.lastname: van Schouwenburg
authors.forename: Willem F
authors.initials: WF
authors.lastname: Lems
authors.forename: Jos W R
authors.initials: JW
authors.lastname: Twisk
authors.forename: Ben A C
authors.initials: BA
authors.lastname: Dijkmans
authors.forename: Lucien
authors.initials: L
authors.lastname: Aarden
authors.forename: Gerrit Jan
authors.initials: GJ
authors.lastname: Wolbink
mesh_terms: D000068879:Adalimumab; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D000917:Antibody Formation; D018501:Antirheumatic Agents / Q000276:immunology* / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012074:Remission Induction; D017211:Treatment Failure
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents; D000068879:Adalimumab