The occurrence of adverse events (AEs), including serious adverse events (SAEs), is more common in children with juvenile idiopathic arthritis (JIA) on biologic therapy than has been previously reported. More than 90% of children experienced at least 1 AE on biologics, and more than one-third suffered an SAE over long-term follow-up in a “real world,” retrospective, observational study reported online December 10, 2014, in Rheumatology. Although AEs and SAEs were more frequent than assumed, these events seldom led to drug discontinuation.
“Our data show a wide spectrum of AEs during biologic therapy as they appear in a real-life setting. One of the strengths of the study is that we included all AEs, whether known to be related to the biologic agent or not, regardless of how many times or when they appeared in a single patient. Moreover, we did not rely on surveys or survey-based registries, but assessed all the available information in patient records, which seemed to be a more reliable method of collecting information,” wrote the authors.
Other strengths of the study included long-term follow-up of more than 4 years in the majority of patients. The main limitation was that it was retrospective and was not able to define causality of AEs with accuracy.
The study included 348 consecutive patients with JIA treated at 3 different tertiary centers in Finland. This amounted to 1516 patient-years: 710 patient-years on etanercept, 591 on infliximab, 188 on adalimumab, 8 on rituximab, 5.3 on anakinra, 6 on abatecept, 4 on tocilizumab, and 1 on golimumab. Median follow-up of an individual patient on biologics was 50.5 months (range, 1-154.7 months). Median age at end of follow-up was 15.9 years (range, 3.8-29 years). Ninety-five percent (n=330) were on disease-modifying antirheumatic drugs (DMARDs) prior to biologics, and 97% received DMARDs during treatment with biologics.
Ninety-two percent (n=319) reported at least 1 AE. Patients without an AE had a significantly shorter median follow-up compared with those who had an AE: 18.8 months versus 52.3 months, respectively (P<.0001). AEs totaled 2902 and 169/100 patient-years. Infections were the most common AE, reported in 274 patients (79%). Other common AEs included infusion or injection site reactions (n=105, 30.2%), flare of uveitis (n=43, 12.4%), and mild elevation of alanine aminotransferase (ALT) <3 times upper limit of normal (n=49, 14.1%).
SAEs were reported in 121 patients (35%) over follow-up, with a total of 173 events and 11.4/100 patient-years. A total of 44 patients (12.6%) had a serious infectious AE. The occurrence of serious infections was significantly higher with ritixumab compared with all other anti-TNFs, with a relative risk of 6.16 (P=.008). A total of 32 patients had more than 1 SAE. Drug therapy was continued unchanged in 150 patients (87%) despite an SAE. In some of these cases, there was a short pause in therapy. No cases of malignancies or tuberculosis were found. New onset uveitis was reported in 9 patients, psoriasis or psoriaform lesions in 13 patients, and inflammatory bowel disease in 6 patients.
Lead author Maarit Tarkiainen, MD, Children’s Hospital, University of Helsinki, Finland, said these data support the use of biologics in juvenile patients. “Most common SAEs were leucopenias and ALT elevations. After these, drug therapy could most often be continued after a short pause. SAEs during treatment with biologics in juvenile patients can mostly be controlled by experienced pediatric rheumatologists,” she said.
Tarkiainen M, et al. Rheumatology. Published online: December 10, 2014.
Last modified: May 21, 2015