Focus on adverse events of tumour necrosis factor α blockade in juvenile idiopathic arthritis in an open monocentric long-term prospective study of 163 patients

Objective: To report adverse events (AEs) seen in a large cohort of patients with juvenile idiopathic arthritis (JIA) treated with tumour necrosis factor (TNF)alpha blockers (infliximab and etanercept). Methods: All patients with JIA treated with infliximab or etanercept at the Paediatric Rheumatologic Centre of the G Pini Institute (Milan, Italy) from November 1999 to February 2006, were enrolled in an open, single-centre, long-term prospective study Results: In all, 163 patients (68 infliximab, 95 etanercept) were enrolled. Mean (SD) age of onset was 6.4 (4.8) years, mean age 17.1 (9.2) years, mean therapy duration 22.9 (17.6) months. A total of 45 patients (32 infliximab, 13 etanercept) failed to respond to or did not tolerate the first therapy and switched to a second one. In all, 208 treatments (81 infliximab, 127 etanercept) were performed. A total of 71 AEs occurred in 51 (62.9%) patients on infliximab and led to discontinuation in 26 (32.1%); 133 AEs occurred in 69 (54.3%) patients on etanercept and led to discontinuation in 18 (14.2%). Some AEs, such as thrombocytopoenia, neuropsychiatric disorders, new onset of Crohn disease and new onset or flare-up of chronic iridocyclitis (CIC), are unusual and have rarely been described before, yet proved to be significant in frequency and/or clinically noteworthy in the large population we followed. Conclusions: In our 6-year study, anti-TNF alpha agents infliximab and etanercept were well tolerated and safe, and were associated with only few serious, but all reversible, AEs. However, such inhibitors are associated with various and numerous AEs. Children and young adults affected by JIA should be carefully monitored so as to limit the risk of AEs during anti-TNF alpha therapy as much as possible.