Increased efficacy of infliximab associated with methotrexate in ankylosing spondylitis

Abstract

Objectives: The aims of this study were to assess the efficacy of infliximab (IFX) combined with methotrexate (MTX) versus IFX alone in the treatment of ankylosing spondylitis (AS).

Methods: The study was a 30weeks open label and prospective study of parallel groups in 19 patients with active AS. These patients had shown incomplete therapeutic response to standard therapy (full dose of non-steroidal anti-inflammatory drugs: NSAIDs) and disease modifying antirheumatic drugs: DMARDs (MTX or sulfasalazine: SLZ) for a period of at least 12 weeks and were treated with IFX (5mg/kg). Patients were divided into two treatment groups according to the previous treatment: in Group A, 9 patients previously treated with 7.5mg/week of MTX were treated with IFX in addition to MTX (IFX+MTX); in Group B, 10 patients previously treated only with NSAIDs were treated with IFX (5mg/kg) as monotherapy (IFX). The primary outcome was improvement in disease activity shown by the BASDAI50 at week 30; the secondary outcome included comparison of the proportions of subjects in each group achieving response criteria proposed by the ASAS group. BASDAI, BASFI, ESR, CRP, pain, inflammation and Patient Global Assessment were also recorded.

Results: Both groups were similar in sex ratio, clinical forms and B27. Differences between groups occurred only in the disease duration and age of the patient. At 14 and 30 weeks only 50% and 10% respectively of the patients from the IFX group achieved BASDAI50 response compared to 89% of patients from the IFX+MTX group. The difference between groups at 30 weeks was statistically significant (p=0.001; percentage of difference: 79%; 95% confidence interval (CI): 26-93%:). ASAS50 was reached in 67% and 55.6% of patients from the IFX+MTX group at 14 and 30 weeks respectively, compared with 30% and 0% of patients from the IFX group The difference between groups at 30 weeks was statistically significant (p=0.011; percentage of difference: 57%; 95% CI: 8-84.7%).

Conclusion: Infliximab in combination with MTX seems to increase the efficacy of the therapeutic response in active AS patients, but more wide-ranging studies are necessary, mainly long-term studies.