Abstract
The aim of this study is to investigate the course of treatment by anti-tumor necrosis factor agents (infliximab and etanercept) in patients with rheumatoid arthritis (RA) and to compare results with each other. 150 patients with RA treated in our institute from November in 2003 to May in 2008 were included. Drug survival rates and severe adverse events were investigated. Analysis of drug survival rates was performed using Kaplan-Meyer’s method and the Log-Rank test. Drug survival rates of both agents when used as both primary and secondary biologics were 79.4% at 12 months, 70.0% at 24 months, 52.5% at 36 months in the case of infliximab and 85.3% at 12 months,83.6% at 24 months, 79.4% at 36 months in the case of etanercept. Mean continuation periods were 26.4 months in the infliximab group and 30.7 months in the etanercept group and the difference was statistically significant (P＝0.04). However, there was no significant difference between two groups when analyzed using data on agents used as primary agents (26.2 months in infliximab group and 29.9 months in etanercept group). There was also no significant difference between the two groups when analyzed using data of agents used after etanercept was commercially available (27.9 months in infliximab group and 30.7 months in etanercept group). 2 cases treated with infliximab developed tuberculosis. 1 case treated with infliximab and 3 cases treated with etanercept died. This study suggested that results of drug survival rates were influenced by baseline characteristics of patients, time when agents were commercially available, dosage used in clinical practice and human anti-chimeric antibody to infliximab.
