Comparable efficacy and safety of treatment with biological agents etanercept and anakinra in children with Juvenile Idiopathic Arthritis in Latvia

Abstract

Background The introduction of biologics holds great promise in the management of the two, often most aggressive and challenging forms of Juvenile Idiopathic Arthritis (JIA) – polyarticular and systemic onset or Still`s disease. JIA is not a single disease and treatment approach varies between types. Recently it has been demonstrated that treatment with anti TNF agent etanercept has a major beneficial effect on children with refractory polyarthritis [1]. Since IL-1 has been shown to be an important cytokine in the pathogenesis of systemic arthritis, therapies directed against this cytokine has been shown to be effective for this form of JIA [2]. Objectives To evaluate treatment efficacy and safety with two different biologics: anti TNF etanercept and anti IL-1 anakinra in patients with polyarthritis and Still`s disease. Methods and materials Data from 32 JIA patients (30 serenegative polyarthritis and 2 Still`s disease), aged 4 to 18 years, receiving treatment with biological agents, were obtained. JIA diagnosis and disease type were confirmed according to the ILAR classification criteria of JIA [3]. Patients unresponsive to prior MTX therapy, were started with combination etanercept (s/c twice a week in a dose 0.4 mg/kg) and methotrexate (MTX) (once a week in a dose 10-15 mg/m 2) with the evaluation of clinical response at the period of 3 and 6 months. The assesment of therapeutical response was made using criteria of preliminary definition of improvement in JIA proposed by Giannini et al. [4]. Results One patient with polyarthritis showed intolerance to etanercept, due to which the drug was discontinued, while 29 patients with polyarticular JIA (14 boys and 15 girls) showed improvement after the combination etanercept and MTX treatment, according to the global physician assesment of the severity of disease (p<0.01), the global assesment of overall well-being determined by the parent (p<0.01) and by the pain severity scale (p<0.01). Due to the lack of response to etanercept in 2 pts with systemic arthritis, treatment was switched to anakinra (in combination with MTX), which showed good therapeutic response and remission was achieved. The clinical and laboratory evaluation of the patients showed decrease in the number of affected joints and decrease in CRP level (p<0.05). Overall in our experience treatment with biologics, except for mild local injection site reactions in some patients, was not connected with the occurence of any severe side effects, opportunistic infections or autoimmune reactions. Conclusions 1) Anti TNF treatment is effective in patients with polyarticular course of JIA, resistant to MTX therapy 2) Patients with systemic arthritis who fail to respond to anti TNF, are improving on anti IL-1 treatment with anakinra, that is according to the literature data 3) Treatment with biologics shows good safety profile 4) The use of the Biologics Registry data is essential to establish the longer-term clinical effectiveness of biologics, as well as their potential for toxicity to help further define the most appropriate use of these agents.