Decreased clinical response to infliximab in ankylosing spondylitis is correlated with anti-infliximab formation

Ann Rheum Dis. 2007 Sep;66(9):1252-4. doi: 10.1136/ard.2007.072397. Epub 2007 May 1.

Abstract

Objectives: Correlation of serum trough infliximab levels and antibodies to infliximab (anti-infliximab) with clinical response in ankylosing spondylitis.

Methods: In accordance with the international ASsessment in Ankylosing Spondylitis (ASAS) consensus statement, patients were treated with infliximab (5 mg/kg) every 6 weeks after a starting regimen. Preinfusion sera were collected at baseline, 24 and 54 weeks. At every visit, the 20% improvement response (ASAS-20) was assessed and laboratory tests performed.

Results: 24 of the 38 (63%) patients fulfilled ASAS-20 response criteria after 24 weeks of treatment and 21 (53%) after 54 weeks. After 54 weeks, 11 (29%) patients showed undetectable serum trough infliximab levels and detectable anti-infliximab; six of these patients developed an infusion reaction. Anti-infliximab was found significantly more often (p = 0.04) in ASAS-20 non-responders compared with responders at week 54. Serum trough infliximab levels were significantly (p<0.0001) lower in patients with (mean 0.02 mg/l) than in those without (12.7 mg/l) anti-infliximab.

Conclusions: In ankylosing spondylitis, high levels of serum trough infliximab correlated with a good clinical response. Detection of anti-infliximab within 54 weeks is associated with undetectable serum trough infliximab levels, reduced response to treatment and increased risk of developing an infusion reaction.

MeSH terms

  • Adult
  • Antibodies / blood
  • Antibodies, Monoclonal / blood
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / therapeutic use*
  • Antirheumatic Agents / blood
  • Antirheumatic Agents / immunology
  • Antirheumatic Agents / therapeutic use*
  • Female
  • Follow-Up Studies
  • HLA-B27 Antigen / analysis
  • Humans
  • Immunoglobulin G / blood
  • Infliximab
  • Male
  • Middle Aged
  • Radioimmunoassay
  • Spondylitis, Ankylosing / drug therapy*
  • Spondylitis, Ankylosing / immunology
  • Statistics, Nonparametric
  • Treatment Failure
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors*

Substances

  • Antibodies
  • Antibodies, Monoclonal
  • Antirheumatic Agents
  • HLA-B27 Antigen
  • Immunoglobulin G
  • Tumor Necrosis Factor-alpha
  • Infliximab