Designing purification strategies for bispecific antibodies based on molecule design

Today there are many variations of antibodies and especially when the fc region isn’t present we may need to think of other binding regions for our affinity capture step. Not only do these molecules have your standard impurities such as HCP, and ligand leach, they could be sensitive to aggregation and have fragments or homodimer impurities present in the expression. Typically a platform approach to purifying antibodies is done with a capture step followed by 1-2 polishing steps. With the new variants, that approach might be different and need for other selectivity perhaps using a more specific affinity resin or a multimodal resins is required to remove those process related impurities. Today’s discussion will focus on three different case studies the first beginning with the capture and polishing of a bispecific antibody utilizing the VL region, the purification of a bispecific antibody utilizing the VH3 region, and an optimization of a two-step method for a bispecific antibody.