Improving developability of an Antigen Binding Fragment by Aspartate Substitutions

Aggregation can be a major challenge in the development of antibody-based pharmaceuticals as it can compromise the product quality during bioprocessing, formulation and drug administration. To avoid aggregation, developability assessment is often run in parallel with functional optimization in the early screening phases to flag and de-select problematic molecules. As developability assessment can be time- and resource demanding, there is a high focus on development of molecule design strategies to engineer molecules with a high developability potential. Previously, Dudgeon et al. (2012) demonstrated how Asp substitutions at specific positions in human variable domains and single-chain variable fragments could decrease the aggregation propensity. Here, we have investigated whether these Asp substitutions would improve the developability potential of a murine antigen binding fragment (Fab). A full combinatorial library consisting of 393 Fab variants with single, double and triple Asp substitutions was first...