DiscussionScaffold binders and bispecific antibodies were heralded as new waves of biopharmaceutical product candidates that would complement monoclonal antibodies, therapeutic proteins and therapeutic peptides. The staggering protein engineering effort in these two novel drug classes will be summarised as well as their more limited progress towards actual novel therapies and the resulting need for further innovation. The importance of targeting related pathways using bispecific antibodies will be exemplified using an anti-infective program. Novel antibody-based therapies will require the identification of novel targets and an example of antibodies against GPCRs as well as the use of phenotypic screening approaches with biologics will be discussed. Finally, enzyme replacement will be discussed as a key modality beyond just rare diseases.