Efficacy of rituximab in the treatment of rheumatoid arthritis. Influence of serologic status, coprescription of methotrexate and prior TNF-alpha inhibitors exposure.

PURPOSE: Rituximab has been shown to be efficient in the treatment of rheumatoid arthritis (RA) when associated with methotrexate (MTX). The purpose of this study was to evaluate the response to this treatment in daily practice in the following three specific situations: rheumatoid factor (RF)-negative RA patients, rituximab monotherapy patients and TNFα inhibitors-naive patients.
METHODS: This retrospective observational study is an exploratory analysis of the response to rituximab. One thousand milligrams (1000 mg) of rituximab was administered twice at an interval of 15 days. Therapeutic response was determined at mean 20 weeks after the infusion on the basis of DAS28 scores and EULAR response criteria.
RESULTS: One hundred and eight patients were included in the study and the responses of 95 of these were evaluated. Of the latter, 75% were EULAR responders. There was no significant difference in EULAR response between patients treated with rituximab and MTX (73.8%) and those who had received rituximab alone (79.3%). Similarly, there was no difference in the number of EULAR responders between patients who had received TNF inhibitor beforehand (74.1%) and those who had not (78.6%). However, interval to retreatment was significantly shorter in TNF inhibitor-naive patients. Lastly, a significant difference (P=0.02) in EULAR response rate was observed between RF-positive patients (84.8%) and RF-negative patients (57.9%). Interval to retreatment was also significantly shorter in RF-negative patients.
CONCLUSION: In our experience, while our RTX efficacy findings appear to be consistent with the results of comparable controlled trials, whether or not in association with MTX, or with prior administration of one or several TNF inhibitors, RF-positive RA patients exhibited a higher EULAR response rate than RF-negative RA patients.