A significant number of children with severe juvenile idiopathic arthritis (JIA) who received etanercept treatment achieved minimal disease activity (MDA), according to data from an observational study recently published in Rheumatology. Independent predictors of MDA included younger age and disease not treated with concurrent oral corticosteroids.

Previous studies have revealed inconsistencies regarding the factors associated with treatment response in patients with JIA, prompting researchers investigate these factors and changes in disease activity in this patient population after an initial year of etanercept treatment.

The researchers followed 496 children with JIA who underwent etanercept treatment for 1 year. They assessed response rates using change in JIA disease activity score-71 (JADAS-71), and defined excellent response as American College of Rheumatology Pediatric Criteria (ACR Pedi) 90, and proportions of patients who achieved MDA at 1 year. 


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Throughout the first year of treatment, 17 patients stopped due to inefficacy, 9 due to adverse events, 7 for additional reasons, and 1 child stopped for remission.

After 1 year, 74% of children reached ACR Pedi 30, 69% reached ACR Pedi 50, 38% reached ACR Pedi 90, and 48% achieved MDA. The results showed that shorter disease duration was an independent predictor of achieving ACR Pedi 90 (odds ratio [OR]: 0.91; 95% confidence interval [CI]: 0.85-0.97). Other independent predictors included no concurrent oral corticosteroid use (OR: 0.48; 95% CI: 0.29-0.80) and history of chronic anterior uveitis (OR: 2.26; 95% CI: 1.08-4.71).

The results showed that independent predictors of achieving MDA at 1 year lincluded younger patients (OR: 0.60; 95% CI: 0.38-0.95) and disease not treated with concurrent oral corticosteroids (OR: 0.57; 95% CI: 0.35-0.93).

“The association with disease duration may reflect the presence of more chronic joint limitations or pain that may be less responsive to anti-TNF therapies,” the authors wrote. “This association between disease duration prior to treatment and greater response on biologic therapy may be an important observation as it is something that clinicians can aim to shorten, and recent treatment strategy trials have shown the benefit of early treatment in [JIA].

These findings are consistent with studies evaluating the efficacy of etanercept in adult patients with rheumatoid arthritis.

Summary and Clinical Applicability

In this observational study, a significant proportion of children achieved favorable ACR Pedi and MDA response scores within 1 year of etanercept treatment initiation.

The researchers suggest that analyses should be conducted to investigate the 5-year long-term remission statistics of children as they enter adulthood. This could help to inform patients and their families about longer-term outcomes with therapy.

“The finding of a greater response in younger children and those with a history of [chronic anterior uveitis] warrants further investigation and may relate to differences in disease phenotype, drug pharmacokinetics or adherence,” the authors concluded.

Limitations and Disclosures

Because this was an observational study that obtained data from a real-world clinical setting, there was missing disease activity data at each time point. The researchers also noted that the 1-year follow-up period was relatively short in regards to disease outcomes, and therefore, the results cannot be used to comment on long-term responses. 

Additionally it is important to note that despite the outcomes reported, there was only one pediatric participant in this study able to discontinue etanercept within the year due to disease remission.

Kimme L. Hyrich received honoraria from Pfizer and Abbvie and Taunton R. Southwood received medical education grants from Pfizer Pharmaceutical Company unrelated to the current study.

Reference

Kearsley-Fleet L, Davies R, Lunt M, et al. Factors associated with improvement in disease activity following initiation of etanercept in children and young people with Juvenile Idiopathic Arthritis: Results from the British Society for Pediatric and Adolescent Rheumatology Etanercept Cohort Study. Rheumatology. 2016;55:840-847. doi: 10.1093/rheumatology/kev434.