Immunoassays (often referred to as ligand-binding assays) are critical at many stages in the development and production of biotherapeutics. The most well-established, conventional format when performing an immunoassay is ELISA, renowned for achieving high specificity, even at very low target concentrations or with subtle differences in target molecular structure. However, ELISA requires complex and time-consuming methodologies together with specialist skills in order to achieve quality results. Assay development is also slow, typically demanding at least two to three weeks for development and optimization of each new assay.
Efforts have been made to improve immunoassay performance, such as introducing multiplex platforms to handle large sample volumes, reducing turnaround times, and, therefore, increasing productivity. Numerous kits offer to reduce assay development times in addition to improving reproducibility. Nevertheless, these steps forward are not without their own issues. For example, cross reactivity, cross talk, and matrix interference often present challenges with standard multiplex assays.
Additional pressure for faster development of robust assays stems from the outsourcing trend. Assays that can be easily transferred between labs and used throughout the biotherapeutics workflow, from research through to GxP environments, are needed. In addition to cost pressures, bioanalytical labs are increasingly faced with demands for faster turnaround times, and the need to carry out a large range of analytical investigations, often made difficult by limited sample availability.
A multiapplication alternative to ELISA available in an open format suitable for a broad spectrum of assays, requiring minimal development time and consuming less sample per assay, is becoming necessary to meet industry demands. Miniaturization and increased automation will allow laboratories to cut project timelines, while eliminating user error and fulfilling requests for increased testing.
Case Study: MedImmune
MedImmune had been using ELISAs for process-related impurity measurement, specifically looking at the levels of host cell proteins (HCPs). The company recently identified a need to increase sample throughput and efficiency in order to handle more projects and meet the requirement for more analytical sample submissions.
Following a review of available technologies, MedImmune selected the Gyros immunoassay platform (Gyrolab™ workstation with Gyrolab Bioaffy CDs) as a prospective solution for carrying out assays at nanoliter scale in a simplified, automated format, with the potential for vastly reducing turnaround times.
A head-to-head comparison using both ELISA and Gyrolab to quantify levels of HCP across 38 in-process samples was carried out. The main goals of the comparison project were to simplify sample preparations, develop more robust assays with broad dynamic ranges and high precision, and achieve higher throughput and faster time to results. Evaluation was based on four main parameters including: sample results, turnaround time, analyst hours, and reagent consumption.