Quantification of anti-drug antibodies against E6011, an anti-fractalkine monoclonal antibody, in monkey and human serum, by an electrochemiluminescence assay

E6011, a humanized anti-fractalkine monoclonal antibody, is under development for the treatment of various inflammatory diseases, such as rheumatoid arthritis. Therapeutic antibodies may induce production of anti-drug antibodies (ADA) that may deteriorate efficacy and/or enhance immunogenic reaction. It is important to have an ADA assay to understand the characteristics of biotherapeutics under development. A simple and reproducible assay has thus been developed for the determination of ADA against E6011 in monkey and human serum by electrochemiluminescence (ECL) detection. An immune-complex of biotinylated E6011, ADA, and rutheniumlabeled E6011 was attached to avidin-coated wells for ECL signal detection. Screening and confirmatory cutpoints were determined to judge negative or positive ADA. Sensitivity of ADA was 1.61 and 1.34 ng/mL in monkey and human serum, respectively. Accuracy and precision of the assay were within +/- 20% and 20%, respectively. Drug tolerance of the assay in monkey and human sera was ensured up to 100 and 1000 mu g/mL E6011 at the surrogate ADA levels of 1 and 4 mu g/mL, respectively. The developed assay was successfully applied to ADA quantification in monkeys and humans in support of immunogenicity assessments.

Automated summary

The development of therapeutic antibodies for inflammatory diseases requires understanding of the characteristics of biotherapeutics. The authors developed a simple and reproducible assay for detecting anti-drug antibodies against E6011 in monkey and human serum, which proved to be accurate and precise.