In Vitro Characterization of ETX1317, a Broad-Spectrum β-Lactamase Inhibitor That Restores and Enhances β-Lactam Activity against Multi-Drug-Resistant Enterobacteriales, Including Carbapenem-Resistant Strains

Multi-drug-resistant Enterobacteriales expressing a wide array of beta-lactamases are emerging as a global health threat in both hospitals and communities. Although several intravenous drugs have recently been approved to address this need, there are no oral Gram-negative agents that are both safe and broadly effective against such pathogens. The lack of an effective oral agent is of concern for common infections which could otherwise be treated in the community but, due to antibiotic resistance, require hospitalization to allow for intravenous therapy. ETX1317 is a novel, broad spectrum, serine beta-lactamase inhibitor of the diazabicyclooctane class that restores the antibacterial activity of multiple beta-lactams against multiple species of multi-drug-resistant Enterobacteriales, including carbapenem-resistant strains. A combination of its oral prodrug, ETX0282, and the oral prodrug of a third-generation cephalosporin, cefpodoxime proxetil, is currently in clinical development. This report describes the biochemical and microbiological properties of ETX1317, which is more potent and demonstrates a greater breadth of inhibition than avibactam, the parenteral prototype of this class of beta-lactamase inhibitors.