Optimization of a Glucagon-Like Peptide 1 Receptor Antagonist Antibody for Treatment of Hyperinsulinism.

Congenital hyperinsulinism (HI) is a genetic disorder in which pancreatic ß-cell insulin secretion is excessive and results in hypoglycemia that, without treatment, can cause brain damage or death. Most patients with loss-of-function mutations in ABCC8 and KCNJ11, the genes encoding the ß-cell ATP-sensitive potassium channel (KATP), are unresponsive to diazoxide, the only U.S. Food and Drug Administration-approved medical therapy and require pancreatectomy. The glucagon-like peptide 1 receptor (GLP-1R) antagonist exendin-(9-39) is an effective therapeutic agent that inhibits insulin secretion in both HI and acquired hyperinsulinism. Previously, we identified a highly potent antagonist antibody, TB-001-003, which was derived from our synthetic antibody libraries that were designed to target G protein-coupled receptors. Here, we designed a combinatorial variant antibody library to optimize the activity of TB-001-003 against GLP-1R and performed phage display on cells overexpressing GLP-1R. One antagonist, TB-222-023, is more potent than exendin-(9-39), also known as avexitide. TB-222-023 effectively decreased insulin secretion in primary isolated pancreatic islets from a mouse model of hyperinsulinism, Sur1-/- mice, and in islets from an infant with HI, and increased plasma glucose levels and decreased the insulin to glucose ratio in Sur1-/- mice. These findings demonstrate that targeting GLP-1R with an antibody antagonist is an effective and innovative strategy for treatment of hyperinsulinism. ARTICLE HIGHLIGHTS: Patients with the most common and severe form of diazoxide-unresponsive congenital hyperinsulinism (HI) require a pancreatectomy. Other second-line therapies are limited in their use because of severe side effects and short half-lives. Therefore, there is a critical need for better therapies. Studies with the glucagon-like peptide 1 receptor (GLP-1R) antagonist, avexitide (exendin-(9-39)), have demonstrated that GLP-1R antagonism is effective at lowering insulin secretion and increasing plasma glucose levels. We have optimized a GLP-1R antagonist antibody with more potent blocking of GLP-1R than avexitide. This antibody therapy is a potential novel and effective treatment for HI.

Defining variant-resistant epitopes targeted by SARS-CoV-2 antibodies: A global consortium study.

Antibody-based therapeutics and vaccines are essential to combat COVID-19 morbidity and mortality after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Multiple mutations in SARS-CoV-2 that could impair antibody defenses propagated in human-to-human transmission and spillover or spillback events between humans and animals. To develop prevention and therapeutic strategies, we formed an international consortium to map the epitope landscape on the SARS-CoV-2 spike protein, defining and structurally illustrating seven receptor binding domain (RBD)­directed antibody communities with distinct footprints and competition profiles. Pseudovirion-based neutralization assays reveal spike mutations, individually and clustered together in variants, that affect antibody function among the communities. Key classes of RBD-targeted antibodies maintain neutralization activity against these emerging SARS-CoV-2 variants. These results provide a framework for selecting antibody treatment cocktails and understanding how viral variants might affect antibody therapeutic efficacy.

Rapid exploration of the epitope coverage produced by an Ebola survivor to guide the discovery of therapeutic antibody cocktails.

BACKGROUND: Development of successful neutralizing antibodies is dependent upon broad epitope coverage to increase the likelihood of achieving therapeutic function. Recent advances in synthetic biology have allowed us to conduct an epitope binning study on a large panel of antibodies identified to bind to Ebola virus glycoprotein with only published sequences. METHODS AND RESULTS: A rapid, first-pass epitope binning experiment revealed seven distinct epitope families that overlapped with known structural epitopes from the literature. A focused set of antibodies was selected from representative clones per bin to guide a second-pass binning that revealed previously unassigned epitopes, confirmed epitopes known to be associated with neutralizing antibodies, and demonstrated asymmetric blocking of EBOV GP from allosteric effectors reported from literature. CONCLUSIONS: Critically, this workflow allows us to probe the epitope landscape of EBOV GP without any prior structural knowledge of the antigen or structural benchmark clones. Incorporating epitope binning on hundreds of antibodies during early stage antibody characterization ensures access to a library's full epitope coverage, aids in the identification of high quality reagents within the library that recapitulate this diversity for use in other studies, and ultimately enables the rational development of therapeutic cocktails that take advantage of multiple mechanisms of action such as cooperative synergistic effects to enhance neutralization function and minimize the risk of mutagenic escape. The use of high-throughput epitope binning during new outbreaks such as the current COVID-19 pandemic is particularly useful in accelerating timelines due to the large amount of information gained in a single experiment.