Biological disease-modifying antirheumatic drugs for rheumatoid factor-negative polyarticular JIA
The approach to managing rheumatoid factor (RF)–negative polyarticular juvenile idiopathic arthritis (JIA), and the role of biological disease-modifying antirheumatic drugs (bDMARDs) in it, is described here. Biological DMARDs are immunomodulatory drugs used by specialists to induce then maintain remission in children and adolescents who have an inadequate response to conventional synthetic DMARD therapy. In the small group of children and adolescents with difficult-to-control polyarthritis, treatment with a bDMARD can minimise polypharmacy and reduce the need for prolonged corticosteroid therapy.
At the time of writing, adalimumab, etanercept and tocilizumab are the only bDMARDs available on the Pharmaceutical Benefits Scheme (PBS) for polyarticular JIA. The usual paediatric dosages (listed in alphabetical order) are:
adalimumab (child 2 years or older and 10 kg to less than 15 kg: 10 mg; 15 kg to less than 30 kg: 20 mg; 30 kg or more: 40 mg) subcutaneously, every 2 weeks adalimumab adalimumab adalimumab
OR
etanercept (child 2 years or older) 0.8 mg/kg up to 50 mg subcutaneously, once weekly1 etanercept etanercept etanercept
OR
less than 30 kg: every 3 weeks
30 kg or more: every 2 weeks
OR
tocilizumab (child 2 years or older and less than 30 kg: 10 mg/kg; 30 kg or more: 8 mg/kg) intravenously, every 4 weeks. tocilizumab tocilizumab tocilizumab
The specialist will determine the appropriate approach to monitoring, screening for infection, and vaccination based on the adverse effect profile of the drug and patient factors (eg disease activity, comorbidities). See also Principles of immunomodulatory drug use.