Development of a Universal Anti-Adalimumab Antibody Standard for Interlaboratory Harmonization

BACKGROUND Therapeutic drug monitoring of adalimumab (ADM) has been introduced recently. When no detectable ADM serum concentrations can be found, the formation of antidrug antibodies (ADA) should be investigated. A variety of assays to measure the occurrence of ADA have been developed. Results are expressed as arbitrary units or as a titration value. The aim was to develop a monoclonal antibody (MA) that could serve as a universal calibrator to quantify the amount of ADA in ADM-treated patients. METHODS Hybridoma technology was used to generate a MA toward ADM. The functionality of the MA was tested in a bridging enzyme linked immunosorbent assay (ELISA) setup and in a cell-based assay. Sera from 25 anti-tumor necrosis factor naive patients with inflammatory bowel disease were used to determine the cutoff values. Sera from 9 ADM-treated patients with inflammatory bowel disease, with undetectable serum concentrations of ADM were used to quantify the ADA response. RESULTS In this study, MA-ADM6A10, an IgG1 that can be used as a calibrator in both an ELISA to quantify the amount of binding antibodies and in a cell-based assay to quantify the amount of neutralizing antibodies, was generated. Combining the results of both assays showed that the sera with high concentrations of anti-ADM binding antibodies also had the highest neutralizing capacity. CONCLUSIONS The availability of a universal calibrator could facilitate the interlaboratory harmonization of antibody titers in patients who develop anti-adalimumab antibodies.