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Qpex Biopharma Announces Publication of Data in Nature Communications on the New Synthetic Lipopeptide Antibiotic QPX9003 Targeting Multidrug-Resistant Gram-negative Pathogens 


QPX9003 addresses carbapenem-resistant pathogens for which the World Health Organization (WHO) has targeted as critical needs for new agents.

SAN DIEGO, March 30, 2022 – Qpex Biopharma, Inc. (Qpex) an antibiotic resistance-focused clinical-stage biopharmaceutical company discovering and developing innovative anti-infective therapies, today announced research published in Nature Communications on the discovery and preclinical properties of QPX9003, a new synthetic lipopeptide antibiotic that is distinct from existing polymyxin-type antibiotics.


The paper, “A synthetic lipopeptide targeting top-priority multidrug-resistant gram-negative pathogens,” describes how researchers from Monash University in Melbourne, Australia in collaboration with scientists from Qpex were able to innovate a new chemical scaffold to disconnect the antimicrobial activity from nephrotoxicity, acute toxicity and inactivation by lung surfactant in vitro. The resulting new lipopeptide QPX9003 is pharmacologically distinct from existing polymyxin drugs with a superior safety and efficacy against experimentally-induced lung infections caused by Pseudomonas aeruginosa, Acinetobacter baumannii and Klebsiella pneumoniae.


“There is an urgent need to develop safer and more potent antibiotics that are not affected by multidrug-resistance mechanisms,” said Professor Jian Li, Ph.D., at Monash University and senior author on the paper. “Our scientists have gained unique insights into the pharmacological properties of polymyxin antibiotics that informed our strategy on how to innovate a new lipopeptide class of antibiotics.”

Currently available polymyxin antibiotics have severely limited clinical utility because of significant safety issues and poor pharmacokinetics with limited efficacy, particularly in pulmonary infections. By optimizing multiple non-conserved positions within the polymyxin scaffold, a new synthetic lipopeptide was developed with studies in preclinical models showing a wider therapeutic window, reduced nephrotoxicity and acute toxicity, and improved drug exposure and efficacy compared to polymyxin B and colistin. The work described in the paper was funded in part by two R01 grants from the National Institute of Allergy and Infectious Diseases of the National Institutes of Health (R01 AI098771 and AI132154).


“The new synthetic lipopeptide QPX9003 potentially represents a marked advance in the treatment of multidrug-resistant pathogens, for which the World Health Organization (WHO) has identified as a critical need for new drugs,” said Michael Dudley, PharmD, president and chief executive officer of Qpex. “The Nature Communications paper and our progress in Phase 1 establishes that QPX9003 has an improved profile that is needed for patients for which there are limited treatment options.”


QPX9003 is currently completing Phase 1 studies. Single-ascending dose in healthy adults have been completed with excellent safety and tolerability results. Single dose pharmacokinetic results from a Phase 1 study will be presented at the 2022 European Conference on Clinical Microbiology and Infectious Diseases (ECCMID) in Lisbon. The clinical study and QPX9003 development is being conducted as part of Qpex’s partnership with the Biomedical Advanced Research and Development Authority (BARDA) within the U.S. Department of Health and Human Services’ Office of the Assistant Secretary for Preparedness and Response, BARDA, under OTA number HHSO100201600026C.

About Qpex Biopharma

Qpex Biopharma has three clinical-stage programs focused on the treatment of infections due to Acinetobacter spp., Pseudomonas aeruginosa, and Enterobacterales-- pathogens that the CDC considers serious or urgent antimicrobial resistance threats and that the World Health Organization (WHO) has designated as a critical need for new drugs. The development of the products in Qpex's portfolio is funded in part with federal funds from the U.S. Department of Health and Human Services' Office of the Assistant Secretary for Preparedness and Response, BARDA, under OTA number HHSO100201600026C.


Qpex’s clinical-stage portfolio comprehensively addresses patient needs in both the inpatient and outpatient settings and includes:

  • OMNIvance®: an IV-administered xeruborbactam (formerly known as QPX7728)-based product with best-in-class coverage of key pathogens, including carbapenem-resistant Acinetobacter, Enterobacterales and Pseudomonas

  • ORAvance™: an orally-administered combination product that delivers xeruborbactam to treat infections that occur in the outpatient and community setting caused by drug-resistant gram-negative bacteria, including fluoroquinolone-, cephalosporin-, or carbapenem-resistant Enterobacteriaceae.

  • QPX9003: a next-generation, IV-administered synthetic lipopeptide with an enhanced therapeutic profile designed to address drug-resistant infections caused by Pseudomonas and Acinetobacter.


The company also has a multi-product collaboration with Brii Biosciences for the development and commercialization of three of its products in greater China. For more information, please visit and follow us on Twitter and LinkedIn

Media Contact:

Katherine Carlyle Smith

Canale Communications


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