Background The TNF Alpha (TNFA) antagonist etanercept (ETN) is approved for the treatment of polyarticular juvenile idiopathic arthritis (JIA) in a dose of 0.8 mg/kg/week. The existing data for TNFA other than ETN suggest a higher efficacy if higher doses are applied.
Objectives To evaluate the efficacy and safety of ETN in doses >0.8 mg/kg/week in JIA patients.
Methods Data from the German Etanercept BIKER Registry were evaluated. Patients were divided into three groups: high dose (HD) (>0.8 mg/kg/week), low (standard) dose (LD) (≤0.8mg/kg/week) and mixed dose (MD) (switching between (>0.8 and ≤0.8mg/kg/week). Efficacy was measured by the PedACR score 30, 50, 70 after 3, 6 and 12 months of treatment. Safety analysis was performed by counting the number of adverse events (AE) per group and per patient. Last observation carried forward (LOCF), intention to treat (ITT) and per protocol (PP) data processing was applied. Statistically Kruskal-Wallis and χ2-tests were used.
Results 547 patients (358 females) with a median age at registry entry of 6.6 years were evaluated: 264 in HD, 109 in the LD and 174 in MD groups.
Efficacy: Independently of the data processing method (LOCF, ITT, PP), efficacy was similar irrespective of the dose. Differences between HD, LD and MD groups could not reach statistical significance. Interestingly the number of patients reaching a higher PedACR score increased with the duration of ETN-treatment, e.g. in the ITT analysis 38.9% of patients reached a PedACR 70 at 3 months of treatment vs. 59.6% at 12 months.
Safety: A total of 72 AE occurred. Divided by the three treatment groups these were: 40 (15.15%) in the HD,
13 (11.93%) in the LD and 19 (10.92%) in the MD groups. The difference could not reach statistical significance (p=0.40).
Conclusions Higher doses of ETN in children with JIA do not seem to add additional benefit to the treatment result. No statistically significant differences could be found between the three treatment groups and therefore in contrast to other TNF Alpha antagonists higher doses shouldn’t be recommended to improve outcome. The duration of treatment with ETN seems to have a positive effect on the response rate to the drug.
Disclosure of Interest None Declared
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