Tocilizumab may slow radiographic progression in patients with systemic or polyarticular-course juvenile idiopathic arthritis: post hoc radiographic analysis from two randomized controlled trials

BACKGROUND: Few clinical trials have investigated the prevention of radiographic progression in children with juvenile idiopathic arthritis treated with antirheumatic drugs. This study aimed to investigate radiographic progression in patients with systemic juvenile idiopathic arthritis (sJIA) and patients with polyarticular-course juvenile idiopathic arthritis (pcJIA) treated with the anti-interleukin-6 receptor antibody tocilizumab for 2 years in the TENDER and CHERISH randomized controlled trials, respectively.

METHODS: Standard radiographs of both wrists and both hands in the posteroanterior view were obtained within 4 weeks of baseline and were repeated at weeks 52 ± 4 and 104 ± 4 in both trials. All films were scored by two independent readers using the adapted Sharp-van der Heijde (aSH) and Poznanski scoring methods. Although the Poznanski score indicates bone growth limitation or cartilage growth decrease, which are not the same as joint space narrowing in rheumatoid arthritis, its change reflects damage to cartilage. Therefore, impairment in the Poznanski score as well as the aSH score was considered as a measure of structural joint damage. Radiographic progression was defined as worsening of radiographic scores beyond the smallest detectable difference.

RESULTS: Poznanski and aSH scores were available at baseline and at one or more postbaseline time points for 33 and 47 of 112 sJIA patients and 61 and 87 of 188 pcJIA patients, respectively, providing a representative subset of the study populations. The inter-reader and intra-reader agreement intra-class correlation coefficient was > 0.8. Median baseline Poznanski and aSH scores, respectively, were - 2.4 and 24.6 for sJIA patients and - 1.5 and 8.0 for pcJIA patients. Compared with baseline, aSH scores remained stable for all sJIA patients at week 52, whereas 9.4% of sJIA patients had radiographic progression according to Poznanski scores at week 52; at 104 weeks, radiographic progression according to aSH and Poznanski scores was observed in 5.4% and 11.5%, respectively. In pcJIA patients, radiographic progression from baseline at 52 weeks and at 104 weeks was 12.5% and 2.9%, respectively, using aSH scoring and 6.5% and 4%, respectively, using Poznanski scoring.

CONCLUSION: Tocilizumab may delay radiographic progression in children with sJIA and children with pcJIA.

TRIAL REGISTRATION: Trial registration numbers and dates: TENDER, NCT00642460 (March 19, 2008); CHERISH, NCT00988221 (October 1, 2009).