A novel SPR-based assay principle allows the measurement of a bispecific drug binding to both targets, and in parallel, the analysis of an additional individual interaction, in a single assay setup.
Surface plasmon resonance (SPR) is increasingly applied in drug discovery, early development and production. However, there are remarkably few reports describing the application of SPR in a regulated environment. Here, we describe a novel SPR-based assay, which enables us to assess the binding activity of a bivalent–bispecific anti-Ang-2/anti-VEGF antibody to both targets in a single setup. Validation of the assay revealed a high level of precision, accuracy, linearity and specificity. Upon analysis of temperature stressed samples it could be shown that firstly, the assay is able to indicate function-loss and secondly, it allows the parallel analysis of an additional interaction. Therefore, the described assay is highly suitable for quality assessment of the Ang-2/VEGF CrossMab. Additionally, the use of SPR in the context of assay development and routine use in a GMP environment is discussed.