A period of 4 weeks (w) has been recommended as the interval between tocilizumab (TCZ) infusions for rheumatoid arthritis (RA). However, treating the patients with TCZ (8 mg/kg), we experienced that longer intervals were also effective. We conducted the study to investigate whether the intervals of TCZ infusions could extend from 4w to 5 or 6w.
This was a retrospective observational study. RA patients who had shown good response to TCZ infusions at 4w intervals were enrolled, and the intervals of TCZ infusions were extended to 5w. Next, the intervals of TCZ infusion were extended to 6w for the patients who had maintained good response with 5w intervals. The patients who had maintained good response for more than two years were estimated as responders.
One hundred patients were enrolled in the present study, and 62 patients maintained good response with 6w-interval infusions, and 28 patients with 5w-interval infusions, indicating that 90% of patients who had shown good response with 4w intervals could extend the intervals from 4w to 5 or 6w.
The present study provides evidence that most of RA patients who showed good response to TCZ infusions at 4w could extend the intervals to 6w or 5w. This finding should be of great interest for both financial and labour reasons.