ANNAPOLIS, MD. – Three novel treatments for gonorrhea, currently in late stages of development, could give clinicians an edge in the fight against antibacterial resistance, according to a federal health official.
The pathogen Neisseria gonorrhoeae is already showing signs of besting first-line therapy ceftriaxone in Japan and parts of Europe, said Carolyn Deal, PhD, chief of the sexually transmitted diseases branch at the National Institute of Allergy and Infectious Diseases (NIAID). And the Centers for Disease Control and Prevention lists N. gonorrhoeae among its “urgent” antibiotic resistance threats.
Dr. Carolyn Deal
“I think we have a new superbug,” Dr. Deal said at the annual scientific meeting of the Infectious Diseases Society for Obstetrics and Gynecology. “In my opinion, it’s just a matter of time in this country.”
But three agents in late-stage clinical trials for uncomplicated urogenital gonorrhea offer promise in fighting the gram-negative bacteria, according to Dr. Deal. The first is solithromycin, manufactured by Cempra. The company has a phase III study underway to compare a single dose of oral solithromycin with intramuscular ceftriaxone plus oral azithromycin for urogenital gonorrhea.
The other two drugs are first-in-class antibacterial agents. In partnership with the NIAID, the company Entasis recently completed a phase II study of zoliflodacin, an oral agent in a novel class of topoisomerase inhibitors. A phase III trial is expected to begin in 2017, also in partnership with the NIAID, according to an Entasis document. The third agent is gepotidacin, a novel triazaacenaphthylene antibacterial agent currently being investigated by GlaxoSmithKline in a phase II study.
Centers for Disease Control and Prevention
This image shows a positive fluorescent antibody test for the gram-negative bacterium Neisseria gonorrhoeae.
Because N. gonorrhoeae poses such an urgent threat, waiting to develop a vaccine is less feasible than working with companies to develop additional antibacterial agents, Dr. Deal said. But taking a compound out of the basic research lab and having enough data to get into the investigational new drug phase is a significant investment, she said, so pharmaceutical manufacturers look for as many indications for a drug as possible.
For instance, solithromycin was initially investigated for community-acquired pneumonia. Gepotidacin initially was developed in partnership with the NIAID and the Biomedical Advanced Research and Development Authority in case of an anthrax attack, Dr. Deal said. “The Entasis product is the only one specifically developed for Neisseria gonorrhoeae,” she said.
One reason that two of the drugs in the pipeline include N. gonorrhoeae as an indication is that the Food and Drug Administration has issued guidance on developing drugs in the area of uncomplicated gonorrhea. That guidance is lacking for nasopharyngeal and rectal gonorrhea, leaving a “vacuum” in the pipeline, Dr. Deal said. “Many of us have come to the conclusion that developing vaccines is the only real long-term solution.”
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