Anti-adalimumab antibodies and adalimumab concentrations in psoriatic arthritis; an association with disease activity at 28 and 52 weeks of follow-up

Ann Rheum Dis. 2014 Dec;73(12):2178-82. doi: 10.1136/annrheumdis-2014-205554. Epub 2014 Aug 12.


Objectives: To investigate the relationship between antidrug antibodies (ADA), adalimumab concentrations and clinical response in patients with psoriatic arthritis (PsA) during 52 weeks of follow-up.

Methods: This prospective cohort study included 103 consecutive patients with PsA. Disease Activity Score of 28 joints (DAS28), Erythrocyte Sedimentation Rate, C reactive protein and Psoriasis Area and Severity Index were assessed. Adalimumab concentrations and ADA were measured in serum trough samples, using an ELISA and a radio immunoassay, respectively.

Results: Adalimumab concentrations were significantly lower at 28 and 52 weeks in patients with detectable ADA compared with patients without detectable ADA (at week 28: 1.3 mg/L (IQR 0.0-3.2) versus 8.7 mg/L (IQR 5.7-11.5), p<0.001; at week 52: 0.9 mg/L (IQR 0.0-2.9) vs 9.4 mg/L (IQR 5.7-12.1), p=0.0001). DAS28 at 28 weeks (2.16 vs 2.95, p=0.023) and 52 weeks (2.19 vs 2.95, p=0.024) showed a significant difference; patients with detectable ADA had a poorer clinical outcome than patients without.

Conclusions: Patients with detectable ADA had lower adalimumab concentrations and a significantly poorer clinical outcome compared with patients in whom ADA were not detected.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adalimumab
  • Adult
  • Antibodies / immunology*
  • Antibodies, Monoclonal, Humanized / blood
  • Antibodies, Monoclonal, Humanized / immunology*
  • Antibodies, Monoclonal, Humanized / therapeutic use
  • Antirheumatic Agents / blood
  • Antirheumatic Agents / immunology*
  • Antirheumatic Agents / therapeutic use
  • Arthritis, Psoriatic / blood
  • Arthritis, Psoriatic / drug therapy*
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Severity of Illness Index
  • Treatment Outcome


  • Antibodies
  • Antibodies, Monoclonal, Humanized
  • Antirheumatic Agents
  • Adalimumab