Treatment responses and their predictors in patients with rheumatoid arthritis treated with biological agents.

Biological agents represent an important advancement in for the treatment of rheumatoid arthritis (RA), but there is a subset of patients who do not improve despite therapy. This study aimed to determine the efficacy of biological agents for RA and to identify clinical factors that are associated with their response. We studied 98 patients with RA who started an initiating biological agent which was selected from infliximab, etanercept, adalimumab and tociliximab at 4 medical institutions. Etanercept was the most frequently used biological agent followed by infliximab although there was a difference in the selection of the biological agents among medical institutions. We found that etanercept achieved the highest treatment response, remission rate and drug survival rate. A high disease activity in the baseline disease activity score-c-reactive protein (CRP) was shown to be a negative predictor of the treatment response, and high patient global assessment was significantly less likely to achieve a good response. At week 4, decreases in 28 swollen joint counts and CRP were useful as predictors for sustaining the efficacy up to week 48. These data demonstrate that assessments of the disease activity at baseline and the early treatment response may be useful in predicting the efficacy and drug survival rate of biological agents.