Analysis of antibody self-interaction by bio-layer interferometry as tool to support lead candidate selection during preformulation and developability assessments

Developability assessment of therapeutic mAb candidates before entering CMC development mitigates the risk of later failure because of manufacturing and stability issues. For mAbs derived from library based screenings, such evaluation starts with the first panning and ends with the selection of a lead candidate. This candidate should show, amongst others, high affine target binding and beneficial conformational as well as chemical stability. In addition, colloidal stability, reflected by the self-interaction propensity, should be superior in order to reduce aggregate formation and unacceptably high viscosity at elevated protein concentrations. Here, we present a study demonstrating the application of self-interaction bio-layer interferometry (SI-BLI) in a developability assessment, including the evaluation of preformulations. We reveal that the formulation rankings based on SI-BLI, DLS and viscosity measurements correlate. SI-BLI provides a deeper understanding of influencing factors on mAb self-interaction such as ionic strength or cation species. The attractive mAb self-interaction propensity was significantly more suppressed by Mg2+ compared to Na+. SI-BLI can be performed in high throughput with minimal material and sample preparation needs. Therefore, it can be applied in early stages of developability assessment going beyond the use of a platform formulation and a small number of analysis, to screen more parameters before proceeding with candidate selection and further extensive development.