Purpose: Administration of a biotherapeutic can result in production of anti-drug antibodies (ADA) response in the host, of various antibody isotypes and affinity. Among them, IgE isotype remains to be the most challenging to measure due to its being the least abundant in blood serum samples and potential interference by high levels of endogenous drug-specific IgG as well as non-specific serum IgE. Surrogate drug-specific IgE positive control is also difficult to generate. Nevertheless, evaluation of drug-specific IgE is important during drug development, as there have been reports of potential correlations between anti-drug IgE formation and anaphylaxis. The purpose of this presentation is to demonstrate the development of a novel anti-drug IgE assay platform with exceptional assay sensitivity and tolerance towards potential interference of drug-specific IgG, residual drug, and total serum IgE antibodies.
Methods: This sandwich ELISA method was developed and characterized for the detection of drug specific IgE antibodies in human serum. A recombinant chimeric anti-drug IgE positive control was generated to facilitate the development and validation of this IgE assay. In this assay, anti-drug IgE was captured by a proprietary reagent, followed by detection by the biotherapeutic.
Results: The assay was capable of detecting 0.4 ng/mL drug-specific IgE. In the presence of 300,000 ng/mL of drug, 5 ng/mL of the IgE positive control could readily be detected (Signal-to-noise (S/N) ratio > 6.0). Additionally, the assay showed great tolerance towards the most common potential interference in anti-drug IgE assays; anti-drug IgE was detectable in the presence of excess specific ADA IgG positive control and non-specific IgE. This assay has been utilized for IgE measurement in multiple drug development programs.
Conclusion: In conclusion, we have developed a drug-specific IgE assay platform that can be generally utilized for the measurement of drug-specific IgE with superior assay sensitivity and tolerance towards potential interference of drug-specific IgGs and non-specific serum IgE as well as the therapeutic drug.