Predictors of JIA treatment response identified
medwireNews: Two studies have identified factors associated with a good response to treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) and tumor necrosis factor (TNF) inhibitors among patients with juvenile idiopathic arthritis (JIA).
In the first study, published in Pediatric Rheumatology, the researchers carried out a retrospective analysis of electronic medical records to investigate the association between baseline characteristics and NSAID monotherapy response among children with systemic JIA.
“[T]here is currently no evidence indicating which children should undergo a trial of NSAID monotherapy and which should not,” explain Anjali Sura (University of Michigan, Ann Arbor, USA) and study co-authors.
They found that approximately a quarter of the 51 patients given NSAID monotherapy achieved clinically inactive disease (CID) after a median of 49 days, and those with CID had a significantly lower mean number of affected joints at initial presentation than those who failed NSAID treatment, at 1.8 versus 5.7 joints.
Patients who achieved CID were also younger (4.8 vs 7.1 years) and were more likely to have C-reactive protein (CRP) levels of 13 mg/dL or lower (92 vs 68%) than those who did not respond to NSAID monotherapy.
When these factors were analyzed together in a multivariate model, a combination of age, joint count, and CRP at diagnosis had a “very strong association” with NSAID monotherapy response, report the researchers.
Although they acknowledge that the analysis was limited by its sample size, meaning that “the number of characteristics that could be considered for analysis was limited,” Sura and team conclude that their study “helps pediatric rheumatologists risk-stratify their patients at diagnosis when choosing whether to pursue a trial of NSAID monotherapy.”
The second study identified switched memory (SwM) B cell levels as a potential predictor of response to TNF inhibitor treatment in children with oligoarticular or polyarticular JIA.
As reported in Arthritis & Rheumatology, Fabrizio De Benedetti (Ospedale Pediatrico Bambino Gesù IRCCS, Rome, Italy) and fellow researchers found that SwM B cells accounted for a significantly higher proportion of the total B cell count in 109 patients with JIA compared with 304 healthy controls, at approximately 12% versus 5%.
Among the 33 JIA patients who were treated with methotrexate plus a TNF inhibitor, those who achieved and maintained remission over a median of 11.2 months experienced a significantly smaller increase in the proportion of SwM B cells than those who were not in remission, at 9.8% versus 41.6%.
Furthermore, the annual increase in SwM B cells was comparable among children who maintained remission with methotrexate plus TNF inhibitor treatment and in healthy controls, at 1.2% per year and 1.5% per year, respectively.
These findings indicate that TNF inhibitors “limit the expansion of SwM B-cells in patients that respond to treatment,” say De Benedetti and colleagues.
They explain that “SwM B-cells are the target of many biologic drugs,” and a reduction in these cells has been associated with favorable outcomes in previous studies.
The researchers conclude that further research should establish a correlation between JIA disease course and SwM B cells, and “validate their usefulness as biomarkers of disease classification and response to treatment.”
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