Objective. The purpose of this study is to evaluate the clinical and hematological effects of tocilizumab in active rheumatoid arthritis (RA) patients. Methods. Fourteen patients with active RA were enrolled in this study. The patients received tocilizumab 8 mg/kg intravenously every four weeks for 6 months. Disease activity, anemia-related factors including serum hepcidin-25, and hematological parameters were monitored at baseline and at 1, 3, and 6 months after the initiation of treatment. Results. Significant reductions in tender joint count, swollen joint count, visual analogue scale, erythrocyte sedimentation rate (ESR), and C-reactive (CRP) protein plus reductions in a 28-joint disease activity score were observed within one month after the first tocilizumab treatment. These effects lasted throughout the six-month study period. In addition, significant improvements in anemia-related factors such as hepcidin-25, ferritin, iron, hemoglobin, red blood cell counts and mean corpuscular volume were observed during the treatment period. Hematological parameters were improved with reductions in counts for leukocytes, monocytes, neutrophils, and platelets. The lymphocyte counts and their subset numbers were unchanged. Changes in hepcidin levels showed significant correlation with changes in CRP, ESR, ferritin, hemoglobin and counts for red blood cells, leukocytes, and neutrophils during the treatment period. Conclusion. This study demonstrates that tocilizumab significantly and meaningfully reduces disease burden in patients with active RA. In addition, tocilizumab diminishes the levels of inflammatory anemia by inhibiting hepcidin production. These clinical data provide evidence of a favorable outcome from tocilizumab in RA. (J Rheum Dis 2016;23:37-46)

Keywords: Rheumatoid arthritis, Tocilizumab, Hepcidins, Anemia, Disease activity