The selective costimulation modulator abatacept is also FDA approved to treat moderately to severely active polyarticular JIA in patients age six years and older.15 Abatacept may be used alone or in combination with MTX. Patients weighing more than 165 pounds should receive a dose of 10 mg/kg as an IV infusion based on body weight; those children weighing less than 165 pounds should be dosed following the adult regimen with a maximum dose of 1,000 mg. Following the initial dose, abatacept should be given at Weeks 2 and 4, then every four weeks thereafter. Some pediatric patients have severe anxiety associated with weekly or more frequent injections. Agents that are administered with less frequent dosing or are administered via IV infusion may ease this anxiety.11
Biologics on the Horizon for JIA
No other biologic agents are approved by the FDA for the treatment of pediatric patients, but there are three agents currently under investigation for JIA. ACZ885 (canakinumab) is currently undergoing phase III clinical trials in patients with systemic JIA.16 This agent is a fully human monoclonal antibody that blocks the inflammatory protein interleukin-1b.17 This agent is already FDA approved for treating cryopyrin-associated periodic syndrome, a rare autoinflammatory disease. Novartis plans to file for the approval of canakinumab for systemic JIA in 2011.18 Certolizumab pegol (Cimzia) is also undergoing phase III clinical trials for the treatment of JIA.19 This PEGylated TNF-α antagonist is currently FDA approved for the treatment of RA and Crohn’s disease in adults.20 Tocilizumab (Actemra), the humanized anti–interleukin-6 receptor monoclonal antibody, is currently in phase III clinical trials for the treatment of systemic JIA.21 In an ongoing clinical trial, patients aged 2 to 17 years receive IV tocilizumab 8 mg/kg (for weight 66 pounds or more) or 12 mg/kg (for weight under 66 pounds) every two weeks for 12 weeks, in addition to NSAIDs plus MTX. These patients are compared with patients receiving only NSAIDs plus MTX.22 Patients receiving tocilizumab have had a prior inadequate clinical response to NSAIDs and corticosteroids. Open-label treatment is expected through 92 weeks with an anticipated sample size of 100 to 500 patients.
If these biologic agents can meet treatment goals in children and prevent joint damage and other negative outcomes, many more treatment options become available once they are adults. All biologics require vigilance and long-term surveillance to monitor for and prevent adverse effects that can occur in the short or long term. There are numerous biologic agents for treating RA in adults and many more in earlier phases of pharmaceutical development for this patient population.23
