Rapid improvement in rheumatoid arthritis patients on combination of methotrexate and infliximab: clinical and magnetic resonance imaging evaluation

The objectives of this study was to assess, using clinical and magnetic resonance imaging (MRI) criteria, the efficacy of combination infliximab therapy in patients with active rheumatoid arthritis (RA) refractory to methotrexate (MTX) treatment and to ascertain whether the changes in MRI parameters correlate with the clinical response. Four infusions of infliximab (3 mg/kg) at weeks 0, 2, 6, and 14 were added to a stable background dose of MTX in 19 patients with active disease. Clinical parameters were assessed before each infusion and at week 14. Dynamic contrast-enhanced MRI examination of the most severely affected wrist was performed at baseline and week 14. Synovitis severity, volume of synovitis, and synovial perfusion indices were evaluated. Significant improvement in all clinical disease activity parameters was seen at week 14 with reduction in C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and DAS28. Sixty-eight percent of patients achieved ACR20. MRI disease activity parameters also significantly decreased after treatment with reduction in grading of synovitis, volume of active synovitis, and perfusion enhancement slope. Significant positive correlations were seen between the baseline volume of synovitis and the pain score (r=0.65), patient global score (r=0.68), and health assessment questionnaire (HAQ) score (r=0.46). In conclusion, addition of infliximab to methotrexate rapidly reduces inflammation in longstanding patients with RA. Assessment of enhancing synovial volume and perfusion indices on serial MRI examination was helpful in documenting the effect of treatment over this short period.