Effectiveness and Safety of TNF Inhibitors in Adults with Juvenile Idiopathic Arthritis

Introduction: Many children with juvenile idiopathic arthritis (JIA) continue to have active disease into adulthood. Adults with JIA are a heterogeneous group and the effects of tumour necrosis factor-inhibitor (TNFi) therapies are not well described. This analysis aims to describe treatment outcomes among patients with JIA starting TNFi for the first time in adulthood. Methods: Patients with arthritis onset <16 years starting their first TNFi were identified from the British Society of Rheumatology Biologics Register. Disease activity outcomes (using DAS28 and HAQ) are presented at one year after start of therapy according to disease pattern. Incidence rates (IR) of adverse events per 1,000 person-years (pyrs) were calculated. Outcomes in patients with polyarticular JIA were compared with a cohort (weighted for age and gender) of patients with rheumatoid arthritis (RA). Results: In 443 adults with JIA starting a first TNFi, disease activity over one year improved across all measures. There were 58 first serious infections (IR 22.3/1,000pyrs); 4 cardiovascular events (IR 1.4/1,000pyrs); 11 uveitis events (IR 4.0/1,000pyrs) and 16 malignancies (IR 3.9/1,000pyrs). Compared with the weighted RA cohort, disease activity improvement was similar; malignancy rates were lower, and uveitis rates much higher. Whilst crude IR were similar, JIA patients had a lower risk of serious infection (hazard ratio 0.5 (95% CI 0.3, 0.9)). Conclusions: This is the largest study to describe disease activity and safety outcomes in adults with JIA receiving TNFi. Disease activity improved after one year in all disease patterns, suggesting TNFi is an effective therapy in this population.