Background Recently due to application of interleukin (IL)-6 inhibitors prognosis for systemic juvenile idiopathic arthritis (sJIA) has significantly improved. 526 children with JIA are under monitoring in Chelyabinsk region, 42 children have sJIA. Tocilizumab is the drug of choice for sJIA treatment. It is registered within the Russian Federation for use in children older than 2 years. In Chelyabinsk Regional Children Hospital tocilizumab has been used for 5 years.

Methods 18 children (12 boys, 6 girls) aged from 2 to 17 (mean age 10.7 years) diagnosed with sJIA were under monitoring. Disease duration was from 6 months to 15 years (mean duration 6 years). JIA was diagnosed based on ILAR diagnostic criteria. SJIA was diagnosed in 16 children, sero-negative polyarthritis was diagnosed in 2 children. Tocilizumab was introduced intravenously every 2 or 4 weeks in dose of 12 mg/kg for children <30 kg or 8 mg/kg for children ≥30 kg. Therapy duration was from 3 months to 5 years (average duration 23 months). Assessment of disease activity and therapy efficiency was conducted in accordance with ACR pedi criteria. Nonparametric statistical methods were used to compare results.

Results Prior to tocilizumab use high disease activity was observed in all children. Average number of joints with active arthritis was 13,5 [6;15] (Me [25;75%]). Average number of joints with functional impairments – 12,5 [6;15]. Average ESR (according to Panchenkov) – 50 [40;60]mm/h, CRP 98,6 [55;139]g/L. Assessment of functional activity according to CHAQ questionnaire- 2,09 [2;2,5]. Activity assessment according to VAS by doctor – 82 [75;90]. Assessment of parents according to VAS 84 [80;90]. No eye lesions were found in children under monitoring. All 16 children with sJIA had fever, hepatosplenomegaly and lymphadenopathy, the rash had 11 children, polyserositis - 8. In 5 children there was a complication in the form of a syndrome of macrophage activation.

During the tocilizumab therapy a decrease in disease activity was observed in all patients. Mean number of joints with active arthritis was 1 [0;2] (Me [25;75%]) (P=0.0002). Mean number of joints with functional impairments – 3 [0;3] (P=0.0003). Average ESR was 4 [3;5]mm/h (P=0.00002), CRP 0,75 [0;1]g/L (P=0.0003). Assessment of functional activity according to CHAQ questionnaire was 0,25 [0;0.5] (P=0.0004). Activity assessment according to VAS by doctor – 16 [10;20] (P=0.0002). Assessment of parents according to VAS 18 [10;20] (P=0.0002).

Clinical disease remission (according to ACR pedi criteria– ≥90%) was observed in 11 patients after 6–9 months of treatment. Remission duration up to now is from 3 months to 4 years. Efficiency according to ACR pedi criteria is 70% in 6 children, 50% in 1.

The drug was well-tolerated. Undesirable effect such as allergic skin reactions were observed only in one child. In one child the lack of efficiency produced by switching to canakinumab. Drug was cancelled in 3 patients due to long-term remission (3–4 years), but 2 of them after a year needed the resumption of therapy in connection with the aggravation of the disease.

Conclusions Tocilizumab therapy was highly effective and safe in patients with JIA. Clinical remission was achieved in 61,1% children. Decrease in disease activity was observed in 39,9% of children. No serious undesirable effects were reported.

Disclosure of Interest None declared