Efficacy of infliximab in resistant psoriatic arthritis

To evaluate the efficacy and safety of the anti-tumor necrosis factor alpha monoclonal antibody infliximab in the treatment of active psoriatic arthritis (PsA) resistant to previous symptom modifying antirheumatic drugs.

Sixteen patients with peripheral active PsA with at least 6 months of methotrexate (MTX) therapy at a stable dosage were treated with infliximab administered at a dosage of 3 mg/kg at 0, 2, 6, 14, 22, and 30 weeks while continuing to receive MTX. Intake of nonsteroidal antiinflammatory drugs and corticosteroids was stable during the study period. Standard clinical assessments, erythrocyte sedimentation rate (ESR), and C reactive protein (CRP) were determined at baseline and at weeks 2, 6, 14, 22, and 30.

By week 2, significant improvements were registered in the number of swollen and tender joints, visual analog scale for pain, patient and doctor global disease assessment scores, Health Assessment Questionnaire, Dougados functional index, ESR, and CRP. At week 30, the percentages of patients satisfying American College of Rheumatology (ACR) 20%, ACR 50%, and ACR 70% response rates were 64%, 57%, and 57%, respectively. In the 3 patients with active axial disease, spinal stiffness and pain resolved almost completely at week 2 and the improvement did not diminish over time. Psoriasis Area Severity Index improvement was 37% at week 2 and 86% at week 30. No patients dropped out for treatment failure. Side effects were observed in 4 of 16 patients, 2 of whom suspended the therapy due to a severe allergic reaction.

In patients with resistant PsA, infliximab is an effective therapy without major side effects.