Objectives: We aimed to evaluate the association between the change in serum IL-6 during the clinical course of tocilizumab (TCZ) therapy and rheumatoid arthritis (RA) disease activity or occurrence of adverse events.
Methods: General laboratory data including serum IL-6 levels and physical findings were obtained every 4 weeks, and, in addition, at the time when any adverse events occurred.
Results: The proportion achieving Clinical Disease Activity Index (CDAI) remission at 52 weeks was significantly lower in 20 patients with serum IL-6 ≥ 30 pg/ml at 12 weeks than 24 patients with serum IL-6 < 30 pg/ml.