Use of a Microfluidic Platform To Evaluate and Predict Reagent Performance in Microtiter Plate-Based Immunoassays

Selection and characterization of antibodies are critically important in establishing robust immunoassays to support the development efforts of vaccines. Plate-based ELISA can be time- and resource-intensive to select initial antibody clones or characterize downstream resupply lots while providing limited information regarding the binding characteristics of the antibodies beyond concentration-response curves. This work applied the microfluidic Gyrolab to holistically evaluate immunoassay reagents through analyses of concentration-response curves as well as antibody-antigen interactions visualized in column images and affinity estimates. We exploited the automation capability of the Gyrolab to reduce the resources (time, reagents, and scientists) required for screening and evaluating antibody reagents. Using a flexible semi-universal assay format, we compared antibody clones for selection and resupply lots of sera and monoclonal antibodies in a simple "plug-and-play" manner without antibody modifications. We found that the performance of antibodies in the Gyrolab correlated well with the trends observed in traditional ELISAs, while the Gyrolab provided additional advantages over plate-based assays such as column images of antibody binding and affinity measurements.

Overcoming disease-specific matrix effect in a clinical pharmacokinetic assay using a microfluidic immunoassay technology

AIM

Etrolizumab, a humanized monoclonal antibody, has demonstrated clinical remission in a Phase II study of ulcerative colitis patients. In the Phase III program, a second indication, Crohn's disease was added. The pharmacokinetic ELISA used in the Phase I/II studies in normal human and ulcerative colitis sera exhibited matrix interference in the Crohn's disease population, necessitating implementation of a new technology. Methodology & results: Optimization of the original ELISA and assay redevelopment using different antibody pairs did not result in substantive improvements, necessitating implementation of an alternative technology for assay development.

CONCLUSION

We highlight the challenges encountered with optimization/redevelopment of the original ELISA and discuss results of the new assay on the Gyros platform.

A semi-universal assay platform to quantitate vaccines with potential applications for biotherapeutics

AIM

Biologics development often requires multiple immunoassays to evaluate both assay reagents and potential drug candidates resulting in extensive analytical development.

METHODOLOGY

We developed a semi-universal, 5-layer platform assay on Gyrolab using secondary antispecies or anti-isotype-specific capture and detection antibodies. We applied the assay to several multivalent vaccines.

RESULTS

Method performance exhibited a median accuracy of 110%, reproducibility of 9% CV and intermediate precision of 11% CV. System suitability criteria were met for 92.5% of the samples and only one out of 31 replicate samples exhibited a %CV greater than 20%.

CONCLUSION

The semi-universal Gyrolab assay allowed assay development without reagent labeling. The format could also be translated into a plate-based assay.

Recommendations for the development and validation of confirmatory anti-drug antibody assays

Identification and characterization of anti-drug antibodies is a critical component of biopharmaceutical drug development. The tiered approach for immunogenicity testing consists of screening, confirmatory, and characterization assays. Herein, we provide recommendations for confirmatory assays by expanding upon published guidance and present common practices across the industry. The authors recommend scientific approaches for development and validation of confirmatory assays using competition methods in ligand-binding assays, along with statistical formulae for routine use and validation. The paper will assist in understanding the confirmatory assay, and carefully implementing validation criteria a priori, as well as during sample analysis. These approaches represent the authors’ current knowledge and practices, with the aim that more uniform practices will be applied across the industry.