Bioanalytics – Biomolecular
2019 PharmSci 360
Bispecific biotherapeutics present a unique bioanalytical challenge for drug development. Based on the mechanism of action, a two-color competitive ligand binding assay using homogeneous time resolved fluorescence technology was designed and initially developed to enable simultaneous measurement of NAb responses to both functional domains of a bispecific monoclonal antibody biotherapeutic. However, the homogeneous NAb assay format was not only prone to drug interference but also resulted in a complicated drug tolerance profile, where circulating drug could cause either false negatives or false positives. A modified Affinity Capture Elution (ACE) method was employed to pre-treat samples and purify NAbs from serum for subsequent NAb assay. This sample pretreatment method effectively separated NAbs from circulating drug and significantly improved assay drug tolerance. Furthermore, in the drug tolerance curve, excessive drug only leads to false negatives. This two-color NAb assay with high drug tolerance enables more accurate NAb assessment and higher throughput bioanalysis.