Neutralizing antibodies (NAbs) to biological drugs may cause loss of therapeutic efficacy and in some cases, loss of endogenous protein function as well. Standard immunoassays can detect anti-drug antibodies, but cannot differentiate neutralizing antibodies, so cell-based assays are often necessary to identify NAbs. Therefore, a key step in the development of a biotherapeutic is the selection and development of an appropriate cell-based bioassay for NAbs, which has traditionally posed significant challenges, especially regarding serum tolerance, sensitivity and specificity.
We describe the development, validation and application of PathHunter® cell-based assays, a novel technology platform to create simple cell-based assays for the detection of NAbs to biological drugs. This technology relies on cells expressing full length, native receptors to create assays that are highly specific, robust and have a homogenous mix-and-read protocol. This enables accurate and sensitive detection of neutralizing antibodies even in high concentrations (up to 100%) of human serum through a simple chemiluminescent output. The technology behind the assay and of case studies will be presented, demonstrating the utility of these cell-based assays for detecting NAbs for a wide variety of biological drugs ranging from proteins, peptides to MAbs and bi-specific antibodies to a variety of targets.