Melinta Therapeutics Demonstrates Potent In Vitro Activity of New Antibiotic Class against Gram Negative ESKAPE Pathogens

NEW HAVEN, Conn, Sept. 8, 2014 (GLOBE NEWSWIRE) -- Melinta Therapeutics today provided an update on the Company's innovative ESKAPE Pathogen Program. The ESKAPE Pathogen Program leverages Melinta's knowledge and experience in crystallography and computational chemistry to generate new classes of antibiotics and new molecules within those classes to treat the extensively drug resistant (XDR) and multi-drug resistant (MDR) "superbug" bacteria, also known as the ESKAPE pathogens. One such molecule, RX-P873, is a member of the pyrrolocytosine class, a new antibiotic class based on a molecular scaffold that has been rationally designed by Melinta for high binding affinity and broad-spectrum activity. In two posters presented at ICAAC, RX-P873 is shown to be active against a range of Gram-negative bacteria, including MDR strains and those highlighted in the Center for Disease Control and Protection's (CDC) list of urgent threats.

Specifically, RX-P873 was tested against Gram-negative species including ten from the enterobacteriaceae family* as well as Pseudomonas aeruginosa and Acinetobacter baumannii. Isolates were collected from the US and Europe in 2012-2013 to be representative of current resistance patterns. RX-P873 was shown have potent activity against the enterobacteriaceae family, inhibiting greater than 97% of isolates. Results show narrow MIC distributions with MIC90 ranging from 0.25 - 4 μg/mL, indicating uniform susceptibility among samples. Notably, RX-P873 was shown to be highly active against P. aeruginosa including strains resistant to ceftazidime or meropenem. It was also the most active agent tested against A. baumannii, showing greater activity than colistin, a treatment considered by many to be the last line of defense for many difficult-to-treat infections[1].

"Melinta's discovery team employs a highly disciplined structure-based design approach that we believe can deliver both next-generation antibiotics and completely new classes, which can be fine-tuned to address current and emerging threats," commented Dr. Erin Duffy, chief scientific officer of Melinta. "As seen in the above studies, RX-P873 shows high and consistent in vitro potency across a variety of Gram-negative pathogens, including those commonly associated with complicated urinary tract infections, complicated intra-abdominal infections and lung infections. We are encouraged by these early stage results and look forward to completing our preclinical efforts and advancing molecules from the ESKAPE Pathogen Program into the clinic."

To date, the ESKAPE Research Program has yielded three novel classes of antibiotics, each built on a unique molecular structure designed to bind to specific validated sites on the bacterial ribosome that have not yet been targeted by approved antibiotics. Melinta has adapted these classes to cover XDR/MDR ESKAPE pathogens, to have a robust resistance profile and to show efficacy in key tissue types in predictive animal models of infection. From those classes, more than 2,500 molecules have been produced. Melinta is completing pre-clinical work on the most promising of these molecules to identify one or more leads to advance into Phase 1 clinical studies.

Summaries of the above in vitro results were presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in posters F-1555b: "In Vitro Activity of RX-P873 Tested against Enterobacteriaceae, P. aeruginosa and Acinetobacter spp," and C-1373: "In vitro activity of a Novel Antibacterial Agent (RX-P873) Against Gram-Negative Bacteria." These and other posters may be retrieved from the Melinta website.

Melinta was invited to participate in two symposia at ICAAC, during which oral presentations were made on the Company's scientific platform. These symposia, titled "Quit Stalling! New Information on the Interaction of Antibiotics with the Bacterial Ribosome" and "Progress on the Ribosome" took place on September 7 at 8:30-10:30 am and September 8 at 3:00-5:00 pm, respectively. ICAAC is being held September 5-9, 2014 in Washington, DC.

About Melinta Therapeutics

Melinta Therapeutics, Inc. is dedicated to the discovery, development and commercialization of groundbreaking antibiotics to overcome drug-resistant, life-threatening infections. The need for new therapies for drug-resistant infections is widely recognized as one of the most serious public health issues facing the world today. To meet this need, Melinta Therapeutics is rapidly progressing its late-stage investigational antibiotic, delafloxacin, which is currently in Phase 3 development for acute bacterial skin and skin structure infections (ABSSSI) and uncomplicated gonorrhea. Delafloxacin has been designated a qualified infectious disease product (QIDP) for both ABSSSI, uncomplicated gonorrhea and community-acquired bacterial pneumonia by the U.S. Food and Drug Administration. A key initiative at Melinta is to develop, through the application of Nobel Prize-winning science, a new class of antibiotics designed to overcome the drug-resistant ESKAPE pathogens known to cause serious hospital infections. Melinta Therapeutics is privately held and backed by lead investor Vatera Healthcare Partners among other private investors. The company is headquartered in New Haven, CT with offices in Lincolnshire, IL.

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* Editor's Note:

- In poster F-1555b, the enterobacteriaceae tested were Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, and Serratia marcescens;

- In poster C-1373, the enterobacteriaceae tested were Enterobacter aerogenes, Enterobacter cloacae, Escherichia coli, and Klebsiella pneumoniae


[1] Soon RL, et al. Int J Antimicrob Agents. 2011 Dec;38(6):493-501.

CONTACT: Melinta Therapeutics Kathy Powell 312-724-9400 Media Contact Aline Schimmel 312-238-8957

Source: Melinta Therapeutics