Efficacy of rituximab therapy in patients with non-systemic juvenile idiopathic arthritis

Juvenile idiopathic arthritis (JIA) is arthritis of unknown cause lasting more than 6 weeks, which starts in children under 16 years old with the exclusion of other joint disorder. According to the recommendations for the treatment of JIA, patients who does not responded to with antirheumatic therapy, we prescribe biological therapy, primarily TNF-alpha inhibitors. Despite their high effectiveness, in some patients, the TNF-alpha inhibitors has no proper therapeutic effect, which requires studying the possibility of using other therapy, in particular- rituximab. Objective. To evaluate the efficacy and safety of rituximab in patients with JIA without systemic manifestations Patients and methods. Retrospective cohort study included 33 patients who received rituximab. Treatment was initiated in the Department of Rheumatology, National Medical Research Center for Children's Health (Moscow) between December 2006 and April 2022. All patients were treated with non-steroid anti-inflammatory drugs (NSAIDs), non-biologic disease-modifying antirheumatic drugs (DMARDs), corticosteroids, biological agents with other mechanism of action. There was ineffectiveness of previous antirheumatic therapy in all patients. Patients were divided into two groups: with RF-positive polyarthritis (n = 30) and other non-systemic JIA (n = 13). Efficacy was evaluated in 1, 3, 6, 9, 12 months after first rituximab infusion and every 6 months till discontinuation or 18 years old achievement. Inactive disease/remission was registered according to Juvenile Arthritis Disease Activity Score (JADAS71) <1, С.Wallace criteria (2011) and The American College of Rheumatology (ACR) Pediatric criteria for assessing joint status (ACR Pedi 30, 50, 70, and 90). Results. Among 16 patients with RF-positive JIA 8 (50%) achieved 90% improvement according to ACR Pedi, inactive disease/remission according to С.Wallace was registered in 12 (75%) 12 months after rituximab initiation. In patients with other nonsystemic JIA (n = 13) 90% improvement according to ACR Pedi was registered in 5 (45%) patients, inactive disease/remission according to С.Wallace was registered in 6 (54, 5%) patients. Conclusion. Rituximab is highly effective in patients with JIA without systemic manifestation, who failed to previous treatment with NSAIDs, DMARDs and biological agents with other mechanism of action and it could be considered as next escalation therapy. Key words: rituximab, juvenile idiopathic arthritis, efficiency of therapy