To assess the response to and safety of long term, high dose (> or = 1 mg/kg/week or > or = 15 mg/m2/week) methotrexate (MTX) administration, in a cohort of 21 children with longstanding, severe juvenile rheumatoid arthritis (JRA).
Children received MTX at an average weekly dose of 27 mg for a mean of 15.2 months. Outcome was assessed using a disease activity score based on changes in concomitant therapy, laboratory parameters, physician's global assessment, and radiologic evaluation.
Seven patients (33%) improved, including one child who achieved complete remission, while 14/21 children (67%) did not benefit from high dose MTX. Subsequently, 6/14 (43%) of the non-responders discontinued high dose MTX and began cyclosporine. Radiologic progression, regardless of clinical outcome, was documented in 10/15 (67%) of the patients. The drug was well tolerated despite mild gastrointestinal symptoms and transient liver enzyme elevation.
The results of this open retrospective pilot trial suggest that high dose MTX is well tolerated, but that its role in the treatment of children with refractory JRA may be limited. Radiologic progression, despite improvement in the clinical status or in the laboratory parameters, supports the hypothesis that MTX acts as a potent antiinflammatory agent.