High-Throughput Engineering of Bispecific Antibodies

Summary Bispecific antibodies are extremely valuable therapeutic biologic molecules and make up a growing number of biologic drugs on the market. However, they are more complicated and riskier to develop than monoclonal antibodies, as there are no high-throughput engineering strategies that reflect the final structural form of the antibody. As a result, liabilities emerge when two antigen-binding domains are put together, like polyreactivity, poor expression, and high viscosity. The standard corrective actions are low-throughput, trial and error approaches, often requiring the discovery of new parental antibodies. Thus, there is an unmet need for new technologies for bispecific IgG-like antibody development. We propose a novel therapeutic, Co-Evolved Bispecific Antibodies (CEBAbs). These therapeutics comprise two different antigen binding (Fab) domains that are engineered with high-throughput technologies. CEBAbs are distinguished from prior bispecific antibodies in that the Fab domains are affinity-matured simultaneously, allowing assays for downstream liabilities to be performed while the sequence-function landscape is being explored. Developing CEBAbs will require a protein engineering platform that accommodates orders of magnitude more throughput than those used for single Fabs. In this proposal we will develop the technical capabilities to correctly display intact, properly paired, full-length bispecific IgGs on the surface of yeast cells. The second major innovation in this work will be the development of long read sequencing capabilities that identifies a full-length bispecific IgG with a single read. Having both of these capabilities will allow us to express, assay and characterize millions of unique bispecific IgGs at high - throughput, providing the necessary technology to gather the data that is essential for engineering high performing bispecific antibodies using AI and machine learning approaches. In Phase II we will exploit this innovative technology to discover and develop an array of therapeutic bispecific antibodies for known targets where bispecific antibodies are expected to provide a new mode of action.