Objectives This study will provide evidence-based medical evidence in the application of infliximab for pediatric rheumatology.

Methods The 45 cases of this study were allocated to treatment group and control group. The treatment group was divided into JIA and JAS subgroup. the disease of them were all in active stage.If the patients took methotrexate (MTX) before enrolling group, the dose must be stabile in 10-15mg/m² per week for at least 3 months. A small dose of non-steroidal anti-inflammatory drugs (NSAID) was allowed. The test group received MTX combined with infliximab intravenous infusion (JIA group: 3 mg kg^–1; JAS group: 5 mg kg^–1); the control group received MTX combined an equal volume of placebo intravenous infusion. The cases of JIA group were injected at 0 weeks, 2 weeks, 6 weeks, 14 weeks, 22 weeks, 30 weeks, and the JAS group were injected at 0 weeks, 2 weeks, 6 weeks, 12 weeks, 18 weeks, 24 weeks. Observe the efficacy at each time point and evaluate whether there were significant differences between treatment and control groups so as to judge whether infliximab could reduce disease activity more effectively and durably.

Results The treatment groups included 12 JIA cases and 7 JAS cases while the control group included 18 JIA cases and 8 JAS cases. A total number of 45 cases achieved the injection. The ACR30 improvement rate of JIA treatment group after two weeks was 66.7%, while the control group was 27.7% (P=0.035). The ACR30 and ACR50 improvement rate of JIA treatment group after 30 weeks were 91.7% and 75%; while the control group was 61.1% (P=0.099) and 22.2% (P=0.004). The ASAS 20 response rate of JAS treatment group after two weeks was 85.7%, which was far higher than 25%, the rate of the control group (P=0.04). The ASAS 20 response rate in the treatment group at the endpoint was 100%, while the rate of control group was 37.5% (P=0.07). The recorded adverse reaction in the process of drug use was visible. 3 children merged with respiratory tract infection. An old JIA children merged with chest distress and polypnea 5 minutes later after the second time intravenous infliximab and the symptoms were disappeared after drug withdrawal. One JIA case of penicillin anaphylaxis appeared with systemic wheal -like rash during the 4th injection, and the rash subsided one hour later with the oral phenergan treatment. Tuberculosis, severe infections and tumors were not found in the Short-term observation.

Conclusions This study shows that MTX combined with infliximab can quickly alleviate joint pain and reduce inflammatory markers compared with single MTX in the treatment of juvenile idiopathic arthritis and juvenile ankylosing spondylitis. The significant difference is more obvious in juvenile ankylosing spondylitis treatment. This study also provides data to support the point that the use of infliximab in children is of good safety. The allergy incidence is even lower than the same type of adult reports. The statistically significant differences did not appear in part of the control study considering that it needed a larger sample to support. The long-term efficacy and safety of infliximab require a large sample and long-term follow-up study.

Disclosure of Interest : None declared

DOI 10.1136/annrheumdis-2014-eular.5363