Prolonged efficacy of etanercept in refractory enthesitis-related arthritis

Abstract

Objective: For many children enthesitis-related arthritis (ERA) causes substantial morbidity, and conventional treatments frequently offer limited efficacy. Tumor necrosis factor-alpha (TNF-alpha) has been found to play a central role in the spondyloarthritides. We investigated the longterm efficacy of the TNF fusion protein etanercept in the treatment of patients with ERA refractory to disease modifying antirheumatic drug (DMARD) therapy.

Methods: Eight patients with active, inflammatory ERA were treated in an open-label pilot trial of twice weekly subcutaneous injections (dosing range of 25 to 37.5 mg twice weekly, 0.2-0.8 mg/kg/dose) of etanercept for 2 years. Outcome measures included duration of morning stiffness, active joint count, hemoglobin, and erythrocyte sedimentation rate (ESR). Patients were permitted concomitant nonsteroidal antiinflammatory drugs (NSAID) and DMARD at stable doses.

Results: Treatment with etanercept resulted in significant improvement in active joint count, hemoglobin, and ESR in all 8 patients within 2 months. Additionally, all patients noted increased mobility and overall well being. Improvement in morning stiffness did not achieve statistical significance. One patient was lost to followup after completing one year of the study. The remaining 7 patients had sustained statistically significant efficacy for active joint count, hemoglobin, and ESR throughout the entire 2-year trial. All patients tolerated etanercept with no side effects.

Conclusion: Despite limited power, these results indicate that etanercept provided a rapid clinical response in our cohort of patients with refractory ERA, who achieved sustained efficacy over a 2-year period.