Anaphylaxis to tocilizumab in patients with rheumatic disease.

Anaphylaxis to tocilizumab has been reported anecdotally. Therefore, we evaluated the incidence of anaphylaxis in patients starting tocilizumab. 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. 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). When we consider tocilizumab treatment, especially in AOSD, we should keep in mind that intensive monitoring for anaphylaxis is necessary.