The efficacy and safety of additional administration of tacrolimus in patients with rheumatoid arthritis who showed an inadequate response to tocilizumab.

Objectives: Tocilizumab (TCZ) shows good retention in patients with rheumatoid arthritis (RA), but no previous reports demonstrated hopeful treatment options against inadequate response to TCZ. Tacrolimus (TAC) has proved to show efficacy against inadequate response to tumor necrosis factor alpha inhibitors, yet its add-on effects on TCZ remain unknown. Methods: Twenty patients with RA (17 women, age 58.6 years, disease duration 12.1 years, prior TCZ duration 2.6 years, 18 intravenous [8mg/kg/month] and 2 subcutaneous [324mg/month] TCZ treatments, methotrexate 6.1mg/week [70.0%]) who showed an inadequate response to TCZ (clinical disease activity index [CDAI] >= 5.8, 18 secondary non-responders) were additionally treated with TAC (1.1mg/day), and enrolled in this 24-week, prospective study. Results: Seventeen patients (85.0%) continued the treatment for 24 weeks. Statistically significant decreases in outcome measures were as follows: disease activity score based on 28 joints with C-reactive protein (DAS28-CRP) from 3.3 at baseline to 2.1 at week 24 (p<0.001), CDAI from 17.7 to 7.6 (p<0.001), and serum matrix metalloproteinase-3 levels from 232.8 to 66.2ng/ml (p<0.001). About 15 patients (75%) achieved low disease activity or remission (DAS28-CRP 2.7 or CDAI <= 10) at week 24. Conclusions: Adding low-dose TAC to inadequate responders to TCZ may be a promising complementary treatment option.