A synthetic lipopeptide targeting top-priority multidrug-resistant Gram-negative pathogens

Area of Science:

• Microbiology
• Medicinal Chemistry
• Pharmacology

Background:

• Multidrug-resistant (MDR) Gram-negative pathogens pose a significant global health threat.
• Existing polymyxin antibiotics (polymyxin B, colistin) are last-resort treatments but have severe toxicity and poor lung penetration.
• Limited development of new antibiotics exacerbates the challenge of MDR infections.

Purpose of the Study:

• To develop a novel synthetic lipopeptide with improved safety and efficacy compared to existing polymyxins.
• To address the limitations of polymyxins, including nephrotoxicity and inadequate pulmonary exposure.
• To create a distinct therapeutic agent effective against critical MDR Gram-negative pathogens in lung infections.

Main Methods:

• Systematic chemical biology optimization of non-conserved positions in the polymyxin scaffold.
• Design and synthesis of a new lipopeptide, F365 (QPX9003), distinct from polymyxin B and colistin.
• Evaluation of F365's safety, pharmacokinetics, and efficacy against MDR pathogens in preclinical models.

Main Results:

• Successfully disconnected therapeutic efficacy from toxicity by optimizing the polymyxin scaffold.
• Developed F365 (QPX9003), a synthetic lipopeptide with a novel structure and pharmacological profile.
• Demonstrated superior safety and efficacy of F365 against lung infections caused by Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae.

Conclusions:

• F365 (QPX9003) represents a promising new class of antibiotics for treating MDR Gram-negative bacterial infections.
• The developed synthetic lipopeptide overcomes key limitations of older polymyxins, particularly for pulmonary applications.
• This advancement offers a much-needed therapeutic option against high-priority MDR pathogens, addressing a critical unmet medical need.