An Enzyme-Linked Immunosorbent Assay for Therapeutic Drug Monitoring of Cetuximab

International audience; Cetuximab is anti-epidermal growth factor receptor monoclonal antibody used in the treatment of colorectal and head and neck cancers. Part of the interindividual differences in response may be explained by interindividual variability in pharmacokinetics. An assay measuring cetuximab serum concentrations is therefore needed. An enzyme-linked immunosorbent assay was developed using microtiter plates sensitized with a recombinant human epidermal growth factor receptor extracellular domain. Lower and upper limits of quantitation and limit of detection were determined. Eight standard calibrators (SCs) and 3 quality controls (QCs), that is, 0.75, 7.5, and 15 mg/L, were tested on 5 occasions on 1 day and on 5 occasions on different days. Trough and peak serum concentrations of cetuximab were measured in 15 patients with metastatic colorectal cancer and I patient with undetermined neoplasia undergoing cetuximab-based chemotherapy. Cetuximab concentrations were described using a 2-compartment population pharmacokinetic model. Imprecision and accuracy of SC and QC were