Efficacy and safety of tocilizumab therapy in patients with systemic juvenile idiopathic arthritis. Results of a retrospective cohort study

The implementation of biologicals into routine clinical practice has significantly changed the course of systemic juvenile idiopathic arthritis (sJIA), substantially increased the efficacy of anti-rheumatic therapy, reduced steroid doses, and improved patients' quality of life. Objective. To assess the efficacy and safety of tocilizumab in patients with sJIA. Patients and methods. This study included 250 sJIA patients who received tocilizumab (258 prescriptions in total). Treatment was initiated in the Department of Rheumatology, National Medical Research Center for Children's Health (Moscow) between July 2009 and February 2021. The American College of Rheumatology (ACR) Pediatric criteria for assessing joint status (ACR Pedi 30, 50, 70, and 90) were used to evaluate treatment efficacy after one year of therapy. Inactive disease/remission was registered according to С.Wallace criteria and the Juvenile Arthritis Disease Activity Score (JADAS71). Results. The majority of patients demonstrated an improvement after one year of therapy: 200 individuals (84.4%) according to ACR Pedi 30, 197 individuals (83.1%) according to ACR Pedi 50, 192 individuals (81.0%) according to ACR Pedi 70, and 182 individuals (76.8%) according to ACR Pedi 90. Inactive disease/remission according to С.Wallace and JADAS71 criteria was registered in 179 patients (75.8%) and 170 patients (71.7%), respectively. Conclusion. After one year of treatment, inactive disease/remission according to ACR Pedi 90 criteria was achieved in 179 patients (75.8%) and 182 patients (76.8%), respectively. Therefore, good treatment results were observed in more than half sJIA patients receiving tocilizumab for a year. Nineteen patients achieved partial drug-free remission, whereas 32 patients achieved complete drug-free remission. Forty-two individuals reported no sJIA exacerbations during follow-up. Key words: biologicals, interleukin-6 receptor inhibitor, systemic juvenile idiopathic arthritis, inactive disease/remission, tocilizumab, cytokines