It is known that the main causative antigenic epitope of cetuximab allergy is galactose-alpha-1,3-galactose (alpha-Gal). In 2013, 13 patients with head and neck cancer received the first administration of cetuximab at Matsue Red Cross Hospital in the western part of Japan, and four of them developed anaphylactic shock (Incidence rate was 31%). In the sera of these patients, both alpha-Gal specific IgE by CAP-FEIA and cetuximab specific IgE by western blotting were detected. Both sensitivity and specificity in 13 patients of these tests were 100%. We therefore aimed to prevent cetuximab-induced anaphylactic shock by performing these tests before the administration. We measured alpha-Gal specific IgE by CAP-FEIA and cetuximab specific IgE by western blotting before the first administration of cetuximab in 206 patients with head and neck cancer, and gave the first dose of cetuximab to the patients who showed negative on both tests. As a result, alpha-Gal-specific IgE was detected in 15 of 206, and cetuximab-specific IgE was detected in 12 of 206. Nine patients showed positive on both tests. Thirty nine of the 188 patients who showed negative on both tests have received cetuximab so far, and 2 of them developed anaphylactic shock (Incidence rate was 5%). Although the incidence rate did not reach to 0%, cetuximab-induced anaphylactic shock could be significantly reduced by prior measurement of alpha-Gal-related specific IgE. The reason why the incidence rate could not be 0% may be because the cutoff value (<0.34 kUA/L) we decided was high.

Measurement of galactose-alpha-1,3-galactose-related specific IgE before the first administration of cetuximab can reduce the incidence of cetuximab-induced anaphylactic shock