Hunting down bacterial resistance

Anti-infective company VenatoRx Pharmaceuticals has developed injectable and orally bioavailable broad-spectrum antibiotics that could help curb the expansion of antimicrobial resistance. The company is now seeking clinical and commercial partnerships.

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VenatoRx Pharmaceuticals, a private, clinical-stage pharmaceutical company, focuses on the discovery and development of new medicines to treat drug-resistant infections.

Founded in 2010 by three antimicrobial pharma research and development (R&D) veterans as a virtual company, with seed funding from a 3-year, multimillion-dollar grant from the National Institutes of Health, VenatoRx set out to implement an ambi­tious plan for developing novel molecules to treat drug-resistant infections. Today, with five projects in the pipeline, a workforce of fifty, a few rounds of ven­ture funding, and the recent award of substantial US government drug discovery contracts from CARB-X and the US Defense Threat Reduction Agency (DTRA), VenatoRx is forging ahead with its plans.

VenatoRx (derived from the Latin word venator, meaning hunter, and Rx, the medical symbol for drugs) has two molecules in advanced stages of development—VNRX-5133 and VNRX-7145, inject­able and orally bioavailable broad-spectrum lacta­mase inhibitors, respectively, with activity against all major subclasses of β-lactamases, including the well-established serine β-lactamases, the emerging metallo-β-lactamases, and different subtypes of ser­ine carbapenemases.

VenatoRx is now seeking to expand its global footprint by entering into clinical and commercial partnerships.

Planning for the future

A wave of resistance has appeared in Gram-negative bacteria, which today account for more than 70% of intensive care unit-based infections. Over the last two decades, Gram-negative bacteria have accelerated their resistance to β-lactam antibiotics, the most widely prescribed class of antibiotic drugs (includ­ing penicillins, cephalosporins, monobactams, and carbapenems). What began as a handful of different β-lactamase subtypes now numbers more than 2,000 different variants. Despite the variations, all of these β-lactamase enzyme variants utilize either a serine-based or a metallo-based active site to inactivate their β-lactam targets.

To counter resistance, β-lactam antibiotics have been combined with protective β-lactamase inhibitors, but existing inhibitors such as clavulanic acid or tazobac­tam are no longer sufficiently effective against the emerging extended-spectrum β-lactamases (ESBLs), or the serine-based and metallo-based carbapenem-hydrolyzing β-lactamases (carbapenemases).

VenatoRx focuses specifically on shutting down these new β-lactamase variants, both serine-based and metallo-based. The company plans to develop its intravenous and oral broad-spectrum protective β-lactamase inhibitors to be ready for the next wave of resistance (carbapenem-resistant Enterobacteriaceae and Pseudomonas).

According to Christopher Burns, president and CEO of VenatoRx, “the trick in antibiotic R&D is to see and solve the next resistance problem while it is still percolating and then arrive into the market just as it explodes”.

Broadest-spectrum β-lactamase inhibitors

Multidrug-resistant (MDR) Gram-negative bacteria have been spreading across the globe. Carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA) in par­ticular, including New Delhi metallo-β-lactamase-1 (NDM-1) and Verona integron-encoded metallo-β- lactamase-expressing ‘superbugs’, pose an unusually high public health risk, including increased mortality rates after infection.

VNRX-5133, VenatoRx’s lead injectable β-lactamase inhibitor, which features potent and selective activity against both serine-β-lactamases and metallo-β- lactamases, has completed phase 1 clinical develop­ment in a fixed combination with the fourth genera­tion cephalosporin cefepime. The company plans to start phase 3 pivotal trials in the second half of 2018. The VNRX-5133/cefepime combination has the poten­tial to be best in class against MDR Gram-negative bacterial infections, including CRE and CRPA (Fig. 1).

VNRX-7145, VenatoRx’s lead orally bioavailable β-lactamase inhibitor, which features potent activity against both extended-spectrum β-lactamases and serine carbapenemases, is in preclinical develop­ment and is expected to start human testing in early 2019. Oral, broad-spectrum treatments against MDR Gram-negative bacteria are urgently needed in the clinical setting to reduce hospitalization time or avoid hospitalization altogether.

Fig. 1 | VenatoRx is developing broad-spectrum medicines to treat drug-resistant infections.

PBP inhibitors, the next-generation antibiotics

In addition to the β-lactamase inhibitors, VenatoRx is developing a completely new class of antibiotics that could dramatically improve the treatment of MDR bacterial infections and turn back the Gram-negative resistance clock back by decades. β-lactam antibiot­ics kill bacteria by blocking the penicillin-binding pro­tein (PBP), a key cell wall synthesis enzyme. VenatoRx is now developing novel PBP inhibitors that target the same mechanism—cell wall synthesis—but repre­sent a new class of non-β-lactam molecules that are thus not susceptible to β-lactamases. With funding from both the DTRA and the aforementioned CARB-X public–private partnership program, this platform could deliver a new wave of standalone antibiotics.

VenatoRx’s nimble structure allows it to quickly adapt to patient and regulatory needs and require­ments as the threat of MDR bacteria intensifies globally. “We made a decision several years ago to step into the path of the coming hurricane while the sun was still shining,” said Burns. “To address the coming storm, one needs to provide the best pos­sible broad-spectrum antibiotic options to the clini­cian for when standard of care no longer works. We believe that VenatoRx is achieving that goal. With the right commercial partners, we can fight back against MDR bacteria both in the US and around the globe.”


Tony Meehan, SVP, Business and
Corporate Development
VenatoRx Pharmaceuticals, Inc.
Malvern, PA, USA
Tel: +1-610-644-8935

Go to the profile of Venatorx Pharmaceuticals

Venatorx Pharmaceuticals

Venatorx Pharmaceuticals is a private pharmaceutical company focused on the discovery and development of novel anti-infectives to treat multi-drug-resistant (MDR) bacterial infections and hard-to-treat viral infections. Founded in 2010, Venatorx has built a world-class in-house R&D organization that has filed over 100 patents spanning multiple research programs. Venatorx has received significant funding awards from the National Institute of Allergy and Infectious Diseases (NIAID) of the National Institutes of Health (NIH); Wellcome Trust; the Biomedical Advanced Research and Development Authority (BARDA), part of the Office of the Assistant Secretary for Preparedness and Response (ASPR) at the U.S. Department of Health and Human Service (HHS); the U.S. Department of Defense’s Defense Threat Reduction Agency (DTRA); and CARB-X, and as well as private equity investments from Versant Ventures, Abingworth and Foresite Capital. Venatorx’s most advanced development-stage product is taniborbactam (formerly VNRX-5133), an injectable beta-lactamase inhibitor (BLI) that features selective and potent in vitro activity against both serine- and metallo-beta-lactamases (MBLs), including ESBL, OXA, KPC, NDM, and VIM enzymes. Venatorx believes that taniborbactam, in a fixed combination with the fourth generation cephalosporin, cefepime, has the potential to provide a valuable broad-spectrum treatment option to meet unmet medical needs in patients with infections due to carbapenem-resistant pathogens including carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPA), suspected polymicrobial infections caused by both gram-negative and gram-positive susceptible pathogens, and bioterror pathogens such as Burkholderia spp. Venatorx initiated enrollment in its Phase 3 trial of cefepime-taniborbactam in patients with complicated urinary tract infections (cUTIs) in August 2019 and expects top-line results by the end of 2020. This project has been funded in whole or in part with federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under Contract No. HHSN272201300019C, The Wellcome Trust under Award No. 360G-Wellcome-101999/Z/13/Z, and the Biomedical Advanced Research and Development Authority, Office of the Assistant Secretary for Preparedness and Response, Department of Health and Human Services under Contract No. HHSO100201900007C. Venatorx’s second development-stage product in clinical development is VNRX-7145, an orally bioavailable BLI that in a fixed combination with the third generation orally bioavailable cephalosporin, ceftibuten, has the potential to rescue activity of the partner antibiotic against ESBLs and key carbapenem-resistant Enterobacteriaceae, including those expressing KPC and OXA carbapenemases. This project has been funded in part with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under Contract No. HHSN272201600029C. Additionally, Venatorx has a broad pipeline of preclinical programs including a novel class of Penicillin-Binding Protein (PBP) inhibitors that are impervious to beta-lactamase-driven resistance, and novel antiviral agents targeting Hepatitis B Virus.

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