Background/Purpose:   Biologic medications have allowed a significant proportion of JIA patients to achieve inactive disease. However, some patients will have ongoing moderate to high disease activity or will not tolerate the medication.  Current treatment recommendations suggest changing biologic medications when inactive or low disease activity is not attained, but the switching patterns and reasons for switching in clinical practice in North America are not currently known.

Methods:   We used the Childhood Arthritis & Rheumatology Research Alliance (CARRA) Registry of clinical data from >55 pediatric rheumatology clinics in the United States and Canada. Individuals with JIA and no prior biologic medication use were included if they newly started a biologic medication on or after enrollment in the registry and had a minimum of 6 months of observable time following medication start.  Individuals with systemic JIA were excluded.  Subjects were labelled switchers if they had subsequent use of any other biologic medication during the 6 month follow up time and labelled non-switchers if they did not.  We compared characteristics of switchers and non-switchers using descriptive statistics and reported patterns of and reasons for switching.

Results: There were 134 biologic-naïve children with JIA who started a biologic medication after enrollment, of whom 14 (10%) switched to a different biologic medication within 6 months (Table). The median time before switching was 107.5 days (interquartile range (IQR) 75 – 133).  The majority of patients had started on etanercept (102, 76%) and switched to adalimumab (9), abatacept (1), infliximab (1), and rituximab (1).  One patient switched from adalimumab to etanercept, and 1 switched from infliximab to tocilizumab. Ineffectiveness was the most common reason for switch (6, 43%), 2 patients switched for intolerance of administration, 2 switched for adverse effects, and 1 each switched for financial cost, parental discretion, and not starting the first biologic.  None of the individuals with persistent oligoarticular disease switched. There was no difference in methotrexate use or presence of uveitis between those who did and did not switch. 

Conclusion: In a multicenter cohort of children with JIA who started a biologic, only 10% of children switched biologic medication in the 6 months after initiation of the first biologic.  Etanercept was the most common first biologic medication and most patients who switched started another TNF inhibitor.  Additional studies are needed to evaluate the clinical predictors of switching, the outcomes following biologic switching, to identify the optimal timing of switching and the preferred second-line agent.