SYDNEY—Australian drug developer Recce Pharmaceuticals has announced new data showing significant in-vivo antibacterial activity in mice treated with its lead compound RECCE 327 against Neisseria gonorrhoeae, the second most common sexually transmitted infection (STI). RECCE 327 is among a new class of synthetic antibiotics with broad-spectrum activity developed for the treatment of blood infections and sepsis derived from E. coli and S. aureus bacteria, including their drug-resistant forms.
An independent contract research organization conducted the study to assess the dose-dependency of the compound and its in-vivo antibacterial activity against N. gonorrhoeae. The study’s results, shared in May 2020, showed the model met its primary endpoint of a significant reduction in bacterial load compared to the control at multiple dosing levels, as measured seven days after dosing.
Recce is developing a new class of broad-spectrum antibiotics with activity against multiple serious and potentially life-threatening multidrug-resistant pathogens, including the potential to remain effective against drug-resistant bacteria even with repeated use. According to the company, there have been no new classes of antibiotics developed in more than 30 years, and antibiotics used to prevent and treat bacterial infections are becoming less effective due to widespread resistance. Antibiotic resistance occurs when bacteria no longer respond to the drugs designed to kill them, and has been caused primarily by decades of overuse and misuse of antibiotics.
“The need for new antibiotics has never been greater, as bacteria have developed resistance to most currently approved antibiotics,” says James Graham, executive director of Recce Pharmaceuticals. “Traditional antibiotics operate by a ‘lock-and-key’ mechanism of action. When a bacterium mutates, or evolves, that mechanism of traditional antibiotics no longer functions because the lock has changed. The new class of compounds synthesized by Recce are polymeric molecules designed to overcome these limitations.”
“N. gonorrhoeae bacteria have developed resistance to all but one class of antibiotics, resulting in an urgent need to find a new class of effective antibiotics to kill the pathogen before it develops resistance to the last recommended treatment,” he continues. “Data from our recent study, along with other previous studies, continue to highlight the potential of RECCE 327 to not only become a potent broad-spectrum antibiotic, but most critically, to continue working against antibiotic resistant bacteria or superbugs even with repeated use.”
The WHO lists N. gonorrhoeae as a priority pathogen on its list of antibiotic-resistant bacteria that pose the greatest threat to human health. The U.S. Centers for Disease Control and Prevention (CDC) estimate that drug-resistant N. gonorrhoeae results in 550,000 infections each year.
The current standard of care to treat gonorrhea is an injection of meropenem, a broad-spectrum carbapenem antibiotic used to treat a variety of bacterial infections. That class of antibiotics, however, has been associated with high rates of bacterial resistance, which has led to restriction of its use on infections caused by resistant organisms.
“Rather than inhibiting a specific bacterial protein, in this case a protein involved in cell wall synthesis, RECCE 327 can overcome potential bacterial mutations through its universal mechanism of action,” explains Graham. “When RECCE 327 enters the bloodstream, it binds to a pathogen’s outer membrane and interacts with the bacterial plasma membrane proteins, weakening the cell. Studies have shown RECCE 327 causes bacteria to burst without affecting healthy cells.”
The company believes that using RECCE 327 as the standard of care may also broadly reduce drug resistance against traditional antibiotics by lowering the selective pressure on bacteria that leads to the development of resistance.
“We believe RECCE 327 will be the drug of choice, having shown both efficacy and resistance against superbugs with its broad-spectrum capability and rapid mechanism of action,” says Graham. “As traditional antibiotics become increasingly weak against resistant N. gonorrhoeae infections, the need for a new and effective treatment that works with repeated use could not be greater. RECCE 327 has the capability to fulfill this role, while taking the selective pressure off existing antibiotics, making them increasingly valuable. This then empowers clinicians to confidently administer the antibiotic at first patient presentation, knowing it will not develop resistance.”
Recce Pharmaceuticals is preparing to support its first-in-human clinical trials. RECCE 327 is patented, wholly owned and manufactured in Australia, and the company plans to develop the new class of broad-spectrum antibiotics for several diverse applications.
According to Graham, “Lead candidate RECCE 327 has demonstrated high potency against a range of Gram-positive and Gram-negative bacteria. While we continue to expand our pipeline, we plan on advancing RECCE 327 and new formulations of the drug for other serious infectious diseases. Synthetic polymer drugs have the potential to be effective against deadly superbugs beyond those that are bacterial in origin, including viruses.”
RECCE 327 was recently awarded a Qualified Infectious Disease Product designation for sepsis under the Generating Antibiotic Initiatives Now Act by the U.S. Food and Drug Administration, which helps to fast-track the compound through the regulatory review process and grants 10 years of market exclusivity post approval. Graham says RECCE antibiotics are easily formulated for topical, nasal, oral or inhaled use, and this versatility will be beneficial when developing antibiotics for indications other than sepsis.
“Having completed its preclinical studies assessing RECCE 327, the company expects to move into its first-in-human Phase 1 trial in the second half of 2020,” Graham reports. “The randomized, double-blind, placebo-controlled, single-ascending dose study will evaluate the safety, tolerability, pharmacokinetic and pharmacodynamic properties of RECCE 327 administered by intravascular infusion. In parallel to this study, we anticipate a topical efficacy trial at a leading teaching hospital in Australia to assess RECCE 327’s efficacy on reducing bacterial load in wounds and assisting in wound closure of skin infections and burns.”