The role of subcutaneous administration of methotrexate in children with juvenile idiopathic arthritis who have failed oral methotrexate

Objective. To describe the outcome of patients with juvenile idiopathic arthritis (JIA) treated with subcutaneous (Sc) methotrexate (MTX) after failing oral MTX (either because of inefficacy or toxicity) in a clinic population. Methods. The study cohort was identified from our clinical database, and consisted of 61 children with JIA treated with MTX between 1988-2001. All patients fulfilled International League Against Rheumatism (ILAR) criteria for JIA and had disease duration of greater than or equal to 6 months and 3 or more active joints before institution of MTX. All patients had a core set of outcome variables assessed at baseline and at 3 months after achieving both maximum oral and SC MTX. Outcome variables included physician global assessment of disease activity, number of active joints, number of joints with limited range of motion, duration of early morning stiffness, and erythrocyte sedimentation rate (ESR). Improvement was defined as at least 30% improvement from baseline in 3 of 5 variables in the core set, with no more than one of the remaining variables worsening by more than 30%. Results. A total of 61 patients, 43 females and 18 males with JIA were studied. The disease subtypes were systemic 8, polyarticular 25 (12 rheumatoid factor positive), oligoarticular 14, enthesitis related arthritis 5, and unclassified 4. Thirty-one patients were switched to SC MTX, 13 of whom had not improved, and 18 who had improved, but had nausea (11) or insufficient clinical improvement (7). After 3 months of SC MTX treatment, 76% of patients were classified as improved and 23% as not improved. Toxicity on SC MTX was less than on oral MTX. Conclusion. Our results suggest that for patients failing oral MTX either because of inefficacy or toxicity, the use of SC MTX has a high likelihood of success with more than 70% of patients achieving clinically significant improvement, without clinically significant toxicity. (J Rheumatol 2004;31:179-82).