IV Antibiotics Potentiator Platform for Treating MDR Gram-Negative Infections in the Hospital
There has been a significant decrease in the number of novel IV antibiotics in development and approved over the past 40 years for the treatment of Gram-negative infections. The physiology of Gram-negative bacteria – specifically the make-up of the outer-membrane of these bacteria – is one of the primary roadblocks hindering innovation.
While Gram-positive bacteria possess a single phospholipid cell membrane, Gram-negative bacteria have a phospholipid inner membrane (akin to the Gram-positive membrane), plus an outer membrane bilayer composed primarily of phospholipid at the inner surface and lipopolysaccharide (LPS) at the outer leaflet. It is this layer of highly polar, negatively charged LPS that excludes many excellent target-based inhibitors, including a trove of clinically useful Gram-positive antibiotics from entering Gram-negative bacteria to do their work.
Unfortunately, a distinct incongruence between chemical properties required for Gram-negative penetration (both membranes), and that imposed by many of the known (and novel) bacterial targets, means that simple (or complex) medicinal chemistry tactics have not been able to provide a solution. Spero Therapeutics believes its IV Potentiator Platform approach (SPR741 & SPR206) to LPS disruption will be the solution.
SPR741 is an IV product that does not have any significant antimicrobial activity on its own. However, when combined with an antibiotic, SPR741 has demonstrated the ability to expand the spectrum and potency of the co-administered antibiotic against Gram-negative bacteria, including organisms identified by the CDC and WHO as urgent and serious threats. SPR741 has demonstrated the ability to expand the spectrum and enhance the potency of more than two dozen existing antibiotics and enabled expanded utility against resistant Gram-negative pathogens. SPR741 is currently in a Phase 1b trial.
Our next generation Potentiator molecule – SPR206 – is an IV direct-acting antibiotic that has shown antibiotic activity against Acinetobacter baumanii and Pseudomonas aeruginosa in preclinical studies. SPR206 is currently in IND-enabling studies.