Anaphylaxis to tocilizumab in patients with rheumatic disease.

Background: Anaphylaxis to tocilizumab has been reported anecdotally. Therefore, we evaluated the incidence of anaphylaxis in patients starting tocilizumab. Materials & methods: This retrospective study included patients with rheumatic disease who were administered tocilizumab from 2013 to 2020. The incidence of anaphylaxis was examined during the first 6 months. Results: During follow-up, four of 171 patients developed anaphylaxis within the third course of infusions. The incidence of anaphylaxis to tocilizumab was higher in patients with adult-onset Still's disease (AOSD) than in those with other rheumatic disease (21.4% in AOSD vs 0.7% in rheumatoid arthritis vs 0% in Takayasu arteritis). Conclusions: When we consider tocilizumab treatment, especially in AOSD, we should keep in mind that intensive monitoring for anaphylaxis is necessary.