Anti-infliximab antibodies in patients with rheumatoid arthritis who require higher doses of infliximab to achieve or maintain a clinical response

J Rheumatol. 2006 Jan;33(1):31-6.


Objective: To determine whether the need to use doses of infliximab greater than 3 mg/kg every 8 weeks to achieve or maintain clinical response in patients with rheumatoid arthritis (RA) is associated with differences in baseline clinical characteristics or anti-infliximab antibodies.

Methods: Baseline clinical characteristics and anti-infliximab levels were evaluated retrospectively in a cohort of 51 consecutive patients with RA treated with infliximab at a single center. Patients were divided into 2 groups for comparison: Group 1 patients achieved and maintained clinical responses with infliximab 3 mg/kg every 8 weeks; Group 2 patients required higher doses.

Results: Thirty-two (63%) patients required infliximab dose escalation (Group 2). There were no statistically significant differences in baseline or clinical characteristics between Group 1 and Group 2 patients. Anti-infliximab antibodies occurred in 47% of Group 2 versus 27% of Group 1 patients, with higher anti-infliximab antibody concentrations in Group 2 patients (mean +/- SD: 18.3 +/- 8.9 g/ml vs 7.5 +/- 4.8 g/ml; p = 0.02). Patients who developed anti-infliximab antibodies were younger and receiving less prednisone at the time of infliximab initiation than patients who did not.

Conclusion: Finding higher anti-infliximab antibody concentrations in patients who needed dose escalation of infliximab to achieve or maintain clinical responses with lower serum trough levels of infliximab suggests that development of anti-infliximab antibodies may reduce clinical efficacy of infliximab in some patients with RA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies / blood
  • Antibodies, Monoclonal / administration & dosage*
  • Antibodies, Monoclonal / immunology*
  • Antirheumatic Agents / administration & dosage*
  • Antirheumatic Agents / immunology*
  • Arthritis, Rheumatoid / drug therapy*
  • Arthritis, Rheumatoid / immunology*
  • Arthritis, Rheumatoid / physiopathology
  • Dose-Response Relationship, Drug
  • Drug Tolerance
  • Female
  • Health Status
  • Humans
  • Infliximab
  • Male
  • Middle Aged
  • Retrospective Studies
  • Severity of Illness Index
  • Treatment Outcome


  • Antibodies
  • Antibodies, Monoclonal
  • Antirheumatic Agents
  • Infliximab