Hypersensitivity reactions
The rate of all ADRs to tocilizumab is reported to be around 8%, among them 0.1-0.7% are DHRs (131). DHRs to tocilizumab are both NIHRs (132,133) and IHRs (134-137). In an adult cohort the incidence of IHRs was reported as 5.5% (136) whereas in a paediatric cohort it was 13.6% (134).
Regarding NIHRs, cases of non-immediate urticaria (138), DRESS (139,140), SJS (141), and AGEP (142) were reported. Younger age, shorter stature, lighter weight, and increased disease activity in the early period of tocilizumab administration have been identified as risk factors for DHRs (143).
Although not standardized, DPTs, SPTs and IDTs were used for diagnosis of IHRs in case reports (134,136). Only one study revealed that STs have a low negative predictive value in NIHR (137).Desensitization to tocilizumab in NIHRs was effectively applied in a weekly scheme with premedication in one case (138). Rapid drug desensitization is successfully and routinely used for IHRs (19,131).