Outcomes with methotrexate (MTX) in patients with persistent oligoarticular juvenile idiopathic arthritis (oligoJIA) vs those with extended oligoJIA and rheumatoid factor (RF)-negative polyarthritis were assessed, and results of this analysis were published in Pediatric Rheumatology.

Researchers noted that patients with persistent oligoJIA receiving MTX were at least as likely as those with extended oligoJIA or polyarticular JIA to enter remission. Approximately half of patients with persistent oligoJIA achieved minimal disease activity (MDA) within 2 years of MTX initiation, while patients with extended oligoJIA achieved remission significantly later than those with persistent oligoJIA or polyarticular JIA.  

Although MTX is the most widely used conventional disease-modifying antirheumatic drug in pediatric rheumatology, there are no evidence-based recommendations for its use in oligoJIA.


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Researchers of the current study extracted data from the German Biologics in Pediatric Rheumatology Registry (BIKER), a national registry of patients receiving biologics for JIA. Patients initiating MTX for the treatment of persistent oligoJIA, extended oligoJIA, or RF-negative polyarthritis were eligible for inclusion in the study. Treatment efficacy was measured using the Juvenile Arthritis Disease Activity Score (JADAS-10), with JADAS-10 of 2 or lower and JADAS-10 of 1 or lower designated as cutoff values for MDA and remission, respectively. Tolerability was measured based on the prevalence of adverse events. Treatment outcomes were compared across JIA subtypes.

Between 2005 and 2011, 1058 children with chronic arthritis were enrolled in the BIKER registry from 28 treatment centers around Germany. Among these patients, 370 (35%) had persistent oligoJIA, 221 (21%) had extended oligoJIA, and 467 (44%) had RF-negative polyarthritis. Sex, age at disease onset, and age at MTX initiation differed between study groups. Uveitis was more common among patients with persistent or extended oligoJIA vs those with RF-negative polyarthritis (P <.001). Baseline mean JADAS-10 score was significantly greater in the polyarthritis group compared with the other 2 groups. The starting MTX dosage ranged from 12.1 to 12.6 mg/m2 weekly and did not differ substantially between groups.

All patient groups displayed significant improvements after MTX initiation. At 24 months, JASDAS-MDA had been achieved by 44%, 38%, and 46% of patients with persistent oligoJIA, extended oligoJIA, and RF-negative polyarthritis, respectively. A total of 33% of the persistent oligoJIA group, 29% of the extended oligoJIA group, and 35% of the RF-negative polyarthritis group achieved JASDAS remission (JASDAS ≤1). Patients with extended oligoJIA achieved remission significantly later than patients in the other groups (P <.001). In addition, the extended oligoJIA group received additional biologic disease-modifying drugs significantly more often than other groups (P <.001). While tolerability was comparable between the groups, patients in the persistent oligoJIA group had the lowest rates of adverse events. No new safety signals were observed.

According to these data, the researchers concluded that patients with persistent oligoJIA are as likely as patients with extended oligoJIA or polyarticular JIA to enter remission with MTX.

Study limitations included the fact that the study had no control group – all participants received treatment with MTX – and baseline remission rates in each subtype of JIA could not be ascertained. 

“Further evaluation of a large patient cohort with JIA on [MTX] is important to develop treat-to-target strategies for patients with oligoJIA as they already exist for patients with polyarthritis,” the researchers concluded.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Raab A, Kallinich T, Huscher D, et al. Outcome of children with oligoarticular juvenile idiopathic arthritis compared to polyarthritis on methotrexate – data of the German BIKER registry. Pediatr Rheumatol Online J. 2021;19(1):41. doi:10.1186/s12969-021-00522-4