Development and validation of a novel SPR-based assay principle for bispecific molecules

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.