Pediatric Rheumatology Online Journal → June 2003 → Medical Treatment → Anti-tumor necrosis factor therapy→ Abstract #53
                                                                August 2003 → Newer Treatments → Anti-Tumor Necrosis Factor Therapy → Abstract #53

CLINICAL RESPONSES TO ETANERCEPT IN SYSTEMIC ARTHRITIS MEASURED BY CORE SET OUTCOME VARIABLES

K. M. Bailey,¹ C. J. Ryder,¹ T. R. Southwood.¹

¹Paediatric Rheumatology, Birmingham Childrens Hospital, Birmingham, United Kingdom

This study has addressed the observation that children with systemic arthritis appear to have a poorer response to etanercept than seen in other forms of JIA. Using core set data, we aimed to evaluate responses to etanercept in systemic arthritis and other forms of JIA.
Methods: Twenty four patients with JIA were commenced on etanercept and assessed prospectively according to a standardised protocol administered at set time intervals. Core set data were recorded. Patients were defined as responders or non-responders at the 30% level (Giannini et al 1998). Data from the 6 month visit on 13 patients were evaluated, 9 with systemic arthritis (SA) and 4 with other forms of JIA (non-SA).
Results: The majority of the patient population (10 of 13 patients) were classed as responders to etanercept; the 3 patients who were non-responders all had SA. Mean percent improvement (MPI) i.e. difference between core set data at initiation of etanercept and at the 6 month evaluation for each variable of the core set was calculated for both the SA and non-SA groups. Overall for both groups, the MPI of each variable was 25%. For 3 variables, the SA group did worse than the non-SA group: restricted joint count (MPI SA: MPI non-SA 37.8:61.3), physician VAS (47.5:67.5) and ESR (45.7:55.2). In contrast, the MPI for the other variables was equivalent: (MPI SA: MPI non-SA) active joint count (73.5:69.0), patient or parent VAS (34.4:36.0), and CHAQ (28.2:32.6). A large difference in disease duration at initiation of etanercept between the two groups was noted: SA=8.4 years: non-SA=3.2 years.
Conclusions: The observation that systemic arthritis does not respond as well to etanercept as other, non-systemic forms of JIA is supported by this study. A difference in disease duration before initiating the drug may contribute to the observed differences. Some disparity between individual variables comprising the "core set" was noted, supporting the need for further research to define clinically useful disease activity and outcome variables in systemic arthritis.