A novel approach to predict cetuximab‐induced hypersensitivity reaction: detection of drug‐specific IgE on basophils

Cetuximab is remarkable for the relatively high rate and severity of hypersensitivity reactions ( HR ) being reported in the literature. Screening for cetuximab‐specific IgE in serum via immunoassay has been found to be useful in preventing HR ; however, these tests are known to have a low positive predictive rate. In an attempt to remedy this, we evaluated the interaction between cetuximab and IgE on basophils for predicting severe cetuximab‐induced HR . Twelve head and neck cancer patients were enrolled in this single‐institution study: four with a history of cetuximab‐induced HR and eight with no such history. Cetuximab‐specific and galactose‐ α ‐1,3‐galactose ( α ‐gal) specific IgEs in serum were measured in vitro using an enzyme‐linked immunosorbent assay ( ELISA ). IgE‐cetuximab binding on basophils was also analyzed to evaluate the decrease in cetuximab molecules on basophils after dissociation of IgE from Fcε RI . The positive predictive value associated with the presence of cetuximab‐ or α ‐gal‐specific IgE in serum was found to be only 0.67, whereas the negative predictive value was 1.00. On the other hand, in all four patients who developed HR , the cetuximab molecules on basophils were decreased significantly due to the dissociation of IgE from basophils ( P  < 0.05). However, this was not the case in patients who did not develop HR . In conclusion, our results strongly imply that the IgE‐cetuximab interaction on basophils may be key to developing improved methods for predicting severe cetuximab‐induced HR .